<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Intersex and can you explain it in depth? [/INST] Intersex people are individuals born with any of several sex characteristics including chromosome patterns, gonads, or genitals that, according to the Office of the United Nations High Commissioner for Human Rights, "do not fit typical binary notions of male or female bodies".Sex assignment at birth usually aligns with a childs anatomical sex and phenotype. The number of births with ambiguous genitals is in the range of 1:2000-1:4500 (0.022% - 0.05%). Other conditions involve atypical chromosomes, gonads, or hormones. Some persons may be assigned and raised as a girl or boy but then identify with another gender later in life, while most continue to identify with their assigned sex. The number of births where the baby is intersex has been reported differently depending on who reports and which definition of intersex is used. Anne Fausto-Sterling and her co-authors suggest that the prevalence of "nondimorphic sexual development" might be as high as 1.7%. A study published by Leonard Sax reports that this figure includes conditions such as Klinefelter syndrome (XXY) which most clinicians do not recognize as intersex, and that if the term is understood to mean only "conditions in which chromosomal sex is inconsistent with phenotypic sex, or in which the phenotype is not classifiable as either male or female", the prevalence of intersex is about 0.018%.Terms used to describe intersex people are contested, and change over time and place. Intersex people were previously referred to as "hermaphrodites" or "congenital eunuchs". In the 19th and 20th centuries, some medical experts devised new nomenclature in an attempt to classify the characteristics that they had observed, the first attempt to create a taxonomic classification system of intersex conditions. Intersex people were categorized as either having "true hermaphroditism", "female pseudohermaphroditism", or "male pseudohermaphroditism". These terms are no longer used, and terms including the word "hermaphrodite" are considered to be misleading, stigmatizing, and scientifically specious in reference to humans. In biology, the term "hermaphrodite" is used to describe an organism that can produce both male and female gametes. Some people with intersex traits use the term "intersex", and some prefer other language. In clinical settings, the term "disorders of sex development" (DSD) has been used since 2006, a shift in language considered controversial since its introduction.
Intersex people face stigmatization and discrimination from birth, or following the discovery of intersex traits at stages of development such as puberty. Intersex people may face infanticide, abandonment, and stigmatization from their families. Globally, some intersex infants and children, such as those with ambiguous outer genitalia, are surgically or hormonally altered to create more socially acceptable sex characteristics. However, this is considered controversial, with no firm evidence of favorable outcomes. Such treatments may involve sterilization. Adults, including elite female athletes, have also been subjects of such treatment. Increasingly, these issues are considered human rights abuses, with statements from international and national human rights and ethics institutions (see intersex human rights). Intersex organizations have also issued statements about human rights violations, including the 2013 Malta declaration of the third International Intersex Forum. In 2011, Christiane Völling became the first intersex person known to have successfully sued for damages in a case brought for non-consensual surgical intervention. In April 2015, Malta became the first country to outlaw non-consensual medical interventions to modify sex anatomy, including that of intersex people.

Terminology
There is no clear consensus definition of intersex and no clear delineation of which specific conditions qualify an individual as intersex. The World Health Organizations International Classification of Diseases (ICD), the American Psychiatric Associations Diagnostic and Statistical Manual of Mental Disorders (DSM), and many medical journals classify intersex traits or conditions among disorders of sex development (DSD).A common adjective for people with disorders of sex development (DSD) is "intersex".

Etymology and definitions
In 1917, Richard Goldschmidt created the term "intersexuality" to refer to a variety of physical sex ambiguities. However, according to The SAGE Encyclopedia of LGBTQ Studies, it wasnt until Anne Fausto Sterling published her article "The Five Sexes: Why Male and Female Are Not Enough" in 1993 that the term reached popularity.

According to the UN Office of the High Commissioner for Human Rights:

Intersex people are born with sex characteristics (including genitals, gonads and chromosome patterns) that do not fit typical binary notions of male or female bodies. Intersex is an umbrella term used to describe a wide range of natural bodily variations.

Attitudes towards the term
Some intersex organizations reference "intersex people" and "intersex variations or traits" while others use more medicalized language such as "people with intersex conditions", or people "with intersex conditions or DSDs (differences of sex development)" and "children born with variations of sex anatomy". In May 2016, interACT published a statement recognizing "increasing general understanding and acceptance of the term intersex".Australian sociological research on 272 "people born with atypical sex characteristics", published in 2016, found that 60% of respondents used the term "intersex" to self-describe their sex characteristics, including people identifying themselves as intersex, describing themselves as having an intersex variation or, in smaller numbers, having an intersex condition. Respondents also commonly used diagnostic labels and referred to their sex chromosomes, with word choices depending on audience.Research on 202 respondents by the Lurie Childrens Hospital, Chicago, and the AIS-DSD Support Group (now known as InterConnect Support Group) published in 2017 found that 80% of Support Group respondents "strongly liked, liked or felt neutral about intersex" as a term, while caregivers were less supportive. The hospital reported that the use of the term "disorders of sex development" may negatively affect care.Another study by a group of childrens hospitals in the United States found that 53% of 133 parent and adolescent participants recruited at five clinics did not like the term "intersex". Participants who were members of support groups were more likely to dislike the term. A "dsd-LIFE" study in 2020 found that around 43% of 179 participants thought the term "intersex" was bad, 20% felt neutral about the term, while the rest thought the term was good.

The term "hermaphrodite"
Historically, the term "hermaphrodite" was used in law to refer to people whose sex was in doubt. The 12th-century Decretum Gratiani states that "Whether an hermaphrodite may witness a testament, depends on which sex prevails" ("Hermafroditus an ad testamentum adhiberi possit, qualitas sexus incalescentis ostendit."). Similarly, the 17th-century English jurist and judge Edward Coke (Lord Coke), wrote in his Institutes of the Lawes of England on laws of succession stating, "Every heire is either a male, a female, or an hermaphrodite, that is both male and female. And an hermaphrodite (which is also called Androgynus) shall be heire, either as male or female, according to that kind of sexe which doth prevaile."During the Victorian era, medical authors attempted to ascertain whether or not humans could be hermaphrodites, adopting a precise biological definition for the term, and making distinctions between "male pseudohermaphrodite", "female pseudohermaphrodite" and especially "true hermaphrodite". These terms, which reflected histology (microscopic appearance) of the gonads, are no longer used. Until the mid-20th century, "hermaphrodite" was used synonymously with "intersex". Medical terminology shifted in the early 21st century, not only due to concerns about language, but also a shift to understandings based on genetics.The Intersex Society of North America has stated that hermaphrodites should not be confused with intersex people and that using "hermaphrodite" to refer to intersex individuals is considered to be stigmatizing and misleading.

Prevalence
Estimates of the number of people who are intersex vary, depending on which conditions are counted as intersex. The now-defunct Intersex Society of North America stated that:

If you ask experts at medical centers how often a child is born so noticeably atypical in terms of genitalia that a specialist in sex differentiation is called in, the number comes out to about 1 in 1500 to 1 in 2000 births [0.07–0.05%]. But a lot more people than that are born with subtler forms of sex anatomy variations, some of which wont show up until later in life.
Anne Fausto-Sterling and her co-authors broadly said in 2000 that "[a]dding the estimates of all known causes of nondimorphic sexual development suggests that approximately 1.7% of all live births do not conform to a Platonic ideal of absolute sex chromosome, gonadal, genital, and hormonal dimorphism"; these publications have been widely quoted by intersex activists. Of the 1.7 percent, 1.5 percentage points (88% of those considered "nondimorphic sexual development" in this figure) consist of individuals with late onset congenital adrenal hyperplasia (LOCAH) which may be asymptomatic but can present after puberty and cause infertility.In response to Fausto-Sterling, Leonard Sax estimated that the prevalence of intersex was about 0.018% of the worlds population, after discounting several conditions including LOCAH, Klinefelter syndrome (47,XXY), Turner syndrome (45,X), the chromosomal variants of 47,XYY and 47,XXX, and vaginal agenesis. Sax reasons that in these conditions chromosomal sex is consistent with phenotypic sex and phenotype is classifiable as either male or female.In a 2003 letter to the editor, political scientist Carrie Hull analyzed the data used by Fausto-Sterling and said the estimated intersex rate should instead have been 0.37%, due to many errors. In a response letter published simultaneously, Fausto-Sterling welcomed the additional analysis and said "I am not invested in a particular final estimate, only that there BE an estimate". A 2018 review reported that the number of births with ambiguous genitals is in the range of 0.02% to 0.05%.The figure of 1.7% is still maintained by Intersex Human Rights Australia "despite its flaws", stating both that the estimate "encapsulates the entire population of people who are stigmatized – or risk stigmatization – due to innate sex characteristics," and that Saxs definitions exclude individuals who experience such stigma and who have helped to establish the intersex movement.The following summarizes prevalences of traits that have been called intersex:

Prevalences of specific conditions can vary across regions. In the Dominican Republic, 5-alpha-reductase deficiency is not uncommon in the town of Las Salinas, resulting in social acceptance of the intersex trait. Men with the trait are called "güevedoces" (Spanish for "eggs at twelve"). 12 out of 13 families had one or more male family members that carried the gene. The overall incidence for the town was 1 in every 90 males were carriers, with other males either non-carriers or non-affected carriers.

History
From early history, societies have been aware of intersex people. Some of the earliest evidence is found in mythology: the Greek historian Diodorus Siculus wrote of the mythological Hermaphroditus in the first century BC, who was "born with a physical body which is a combination of that of a man and that of a woman", and reputedly possessed supernatural properties. He also recounted the lives of Diophantus of Abae and Callon of Epidaurus. Ardhanarishvara, an androgynous composite form of male deity Shiva and female deity Parvati, originated in Kushan culture as far back as the first century AD. A statue depicting Ardhanarishvara is included in Indias Meenakshi Temple; this statue clearly shows both male and female bodily elements.Hippocrates (c. 460 – c. 370 BC Greek physician) and Galen (129 – c. 200/216 AD Roman physician, surgeon and philosopher) both viewed sex as a spectrum between men and women, with "many shades in between, including hermaphrodites, a perfect balance of male and female". Pliny the Elder (AD 23/24–79) the Roman naturalist described "those who are born of both sexes, whom we call hermaphrodites, at one time androgyni" (from the Greek andr-, "man," and gyn-, "woman"). Augustine (354 – 28 August 430 AD) the influential Catholic theologian wrote in The Literal Meaning of Genesis that humans were created in two sexes, despite "as happens in some births, in the case of what we call androgynes".In medieval and early modern European societies, Roman law, post-classical canon law, and later common law, referred to a persons sex as male, female or hermaphrodite, with legal rights as male or female depending on the characteristics that appeared most dominant. The 12th century Decretum Gratiani states that "Whether an hermaphrodite may witness a testament, depends on which sex prevails". The foundation of common law, the 17th Century Institutes of the Lawes of England described how a hermaphrodite could inherit "either as male or female, according to that kind of sexe which doth prevaile." Legal cases have been described in canon law and elsewhere over the centuries.
Some non-European societies have sex or gender systems that recognize more than the two categories of male/man and female/woman. Some of these cultures, for instance the South-Asian Hijra communities, may include intersex people in a third gender category. Although–according to Morgan Holmes–early Western anthropologists categorized such cultures "primitive," Holmes has argued that analyses of these cultures have been simplistic or romanticized and fail to take account of the ways that subjects of all categories are treated.During the Victorian era, medical authors introduced the terms "true hermaphrodite" for an individual who has both ovarian and testicular tissue, "male pseudo-hermaphrodite" for a person with testicular tissue, but either female or ambiguous sexual anatomy, and "female pseudo-hermaphrodite" for a person with ovarian tissue, but either male or ambiguous sexual anatomy. Some later shifts in terminology have reflected advances in genetics, while other shifts are suggested to be due to pejorative associations.The term "intersexuality" was coined by Richard Goldschmidt in 1917. The first suggestion to replace the term "hermaphrodite" with "intersex" was made by Cawadias in the 1940s.Since the rise of modern medical science, some intersex people with ambiguous external genitalia have had their genitalia surgically modified to resemble either female or male genitals. Surgeons pinpointed intersex babies as a "social emergency" when born. An optimal gender policy, initially developed by John Money, stated that early intervention helped avoid gender identity confusion, but this lacks evidence. Early interventions have adverse consequences for psychological and physical health. Since advances in surgery have made it possible for intersex conditions to be concealed, many people are not aware of how frequently intersex conditions arise in human beings or that they occur at all.Dialogue between what were once antagonistic groups of activists and clinicians has led to only slight changes in medical policies and how intersex patients and their families are treated in some locations. In 2011, Christiane Völling became the first intersex person known to have successfully sued for damages in a case brought for non-consensual surgical intervention. In April 2015, Malta became the first country to outlaw non-consensual medical interventions to modify sex anatomy, including that of intersex people. Many civil society organizations and human rights institutions now call for an end to unnecessary "normalizing" interventions, including in the Malta declaration.

Human rights and legal issues
Human rights institutions are placing increasing scrutiny on harmful practices and issues of discrimination against intersex people. These issues have been addressed by a rapidly increasing number of international institutions including, in 2015, the Council of Europe, the United Nations Office of the United Nations High Commissioner for Human Rights and the World Health Organization (WHO). These developments have been accompanied by International Intersex Forums and increased cooperation amongst civil society organizations. However, the implementation, codification, and enforcement of intersex human rights in national legal systems remains slow.

Physical integrity and bodily autonomy
Stigmatization and discrimination from birth may include infanticide, abandonment, and the stigmatization of families. The birth of an intersex child was often viewed as a curse or a sign of a witch mother, especially in parts of Africa. Abandonments and infanticides have been reported in Uganda, Kenya, South Asia, and China.Infants, children and adolescents also experience "normalising" interventions on intersex persons that are medically unnecessary and the pathologisation of variations in sex characteristics. In countries where the human rights of intersex people have been studied, medical interventions to modify the sex characteristics of intersex people have still taken place without the consent of the intersex person. Interventions have been described by human rights defenders as a violation of many rights, including (but not limited to) bodily integrity, non-discrimination, privacy, and experimentation. These interventions have frequently been performed with the consent of the intersex persons parents, when the person is legally too young to consent. Such interventions have been criticized by the WHO, other UN bodies such as the Office of the High Commissioner for Human Rights, and an increasing number of regional and national institutions due to their adverse consequences, including trauma, impact on sexual function and sensation, and violation of rights to physical and mental integrity. The UN organizations decided that infant intervention should not be allowed, in favor of waiting for the child to mature enough to be a part of the decision-making – this allows for a decision to be made with total consent. In April 2015, Malta became the first country to outlaw surgical intervention without consent. In the same year, the Council of Europe became the first institution to state that intersex people have the right not to undergo sex affirmation interventions.

Anti-discrimination and equal treatment
People born with intersex bodies are seen as different. Intersex infants, children, adolescents and adults "are often stigmatized and subjected to multiple human rights violations", including discrimination in education, healthcare, employment, sport, and public services. Several countries have so far explicitly protected intersex people from discrimination, with landmarks including South Africa, Australia, and, most comprehensively, Malta.

Remedies and claims for compensation
Claims for compensation and remedies for human rights abuses include the 2011 case of Christiane Völling in Germany. A second case was adjudicated in Chile in 2012, involving a child and his parents. A further successful case in Germany, taken by Michaela Raab, was reported in 2015. In the United States, the Minor Child (M.C. v Aaronson) lawsuit was "a medical malpractice case related to the informed consent for a surgery performed on the Crawfords adopted child (known as M.C.) at [Medical University of South Carolina] in April 2006". The case was one of the first lawsuit of its kind to challenge "legal, ethical, and medical issues regarding genital-normalizing surgery" in minors, and was eventually settled out of court by the Medical University of South Carolina for $440,000 in 2017.

Information and support
Access to information, medical records, peer and other counselling and support. With the rise of modern medical science in Western societies, a secrecy-based model was also adopted, in the belief that this was necessary to ensure normal physical and psychosocial development.

Legal recognition
The Asia Pacific Forum of National Human Rights Institutions states that legal recognition is firstly "about intersex people who have been issued a male or a female birth certificate being able to enjoy the same legal rights as other men and women." In some regions, obtaining any form of birth certification may be an issue. A Kenyan court case in 2014 established the right of an intersex boy, "Baby A", to a birth certificate.Like all individuals, some intersex individuals may be raised as a certain sex (male or female) but then identify with another later in life, while most do not. Recognition of third sex or gender classifications occurs in several countries, However, it is controversial when it becomes assumed or coercive, as is the case with some German infants. Sociological research in Australia, a country with a third X sex classification, shows that 19% of people born with atypical sex characteristics selected an "X" or "other" option, while 75% of survey respondents self-described as male or female (52% as women, 23% as men), and 6% as unsure.

LGBT and LGBTI
Intersex conditions can be contrasted with transgender gender identities and the attached gender dysphoria a transgender person may feel, wherein their gender identity does not match their assigned sex. However, some people are both intersex and transgender; though intersex people by definition have variable sex characteristics that do not align with either typically male or female, this may be considered separate to an individuals assigned gender, the way they are raised and perceived, and their internal gender identity. A 2012 clinical review paper found that between 8.5% and 20% of people with intersex variations experienced gender dysphoria. In an analysis of the use of preimplantation genetic diagnosis to eliminate intersex traits, Behrmann and Ravitsky state: "Parental choice against intersex may ... conceal biases against same-sex attractedness and gender nonconformity."The relationship of intersex people and communities to LGBTQ communities is complex, but intersex people are often added to the LGBT acronym, resulting in the acronym LGBTI. Emi Koyama describes how inclusion of intersex in LGBTI can fail to address intersex-specific human rights issues, including creating false impressions "that intersex peoples rights are protected" by laws protecting LGBT people, and failing to acknowledge that many intersex people are not LGBT. Organisation Intersex International Australia states that some intersex individuals are homosexual, and some are heterosexual, but "LGBTI activism has fought for the rights of people who fall outside of expected binary sex and gender norms." Julius Kaggwa of SIPD Uganda has written that, while the gay community "offers us a place of relative safety, it is also oblivious to our specific needs". Mauro Cabral has written that transgender people and organizations "need to stop approaching intersex issues as if they were trans issues", including use of intersex conditions and people as a means of explaining being transgender; "we can collaborate a lot with the intersex movement by making it clear how wrong that approach is".

In society
Fiction, literature and media
An intersex character is the narrator in Jeffrey Eugenides Pulitzer Prize-winning novel Middlesex.
The memoir, Born Both: An Intersex Life (Hachette Books, 2017), by intersex author and activist Hida Viloria, received strong praise from The New York Times Book Review, The Washington Post, Rolling Stone, People Magazine, and Psychology Today, was one of School Library Journals 2017 Top Ten Adult Books for Teens, and was a 2018 Lambda Literary Award nominee.
Television works about intersex and films about intersex are scarce. The Spanish-language film XXY won the Critics Week grand prize at the 2007 Cannes Film Festival and the ACID/CCAS Support Award. Faking It is notable for providing both the first intersex main character in a television show, and televisions first intersex character played by an intersex actor.

Civil society institutions
Intersex peer support and advocacy organizations have existed since at least 1985, with the establishment of the Androgen Insensitivity Syndrome Support Group Australia in 1985. The Androgen Insensitivity Syndrome Support Group (UK) was established in 1988. The Intersex Society of North America (ISNA) may have been one of the first intersex civil society organizations to have been open to people regardless of diagnosis; it was active from 1993 to 2008.

Events
Intersex Awareness Day is an internationally observed civil awareness day designed to highlight the challenges faced by intersex people, occurring annually on 26 October. It marks the first public demonstration by intersex people, which took place in Boston on 26 October 1996, outside a venue where the American Academy of Pediatrics was holding its annual conference.Intersex Day of Remembrance, also known as Intersex Solidarity Day, is an internationally observed civil awareness day designed to highlight issues faced by intersex people, occurring annually on 8 November. It marks the birthday of Herculine Barbin, a French intersex person whose memoirs were later published by Michel Foucault in Herculine Barbin: Being the Recently Discovered Memoirs of a Nineteenth-century French Hermaphrodite.

Flag
The intersex flag was created in July 2013 by Morgan Carpenter of Intersex Human Rights Australia to create a flag "that is not derivative, but is yet firmly grounded in meaning". The circle is described as "unbroken and unornamented, symbolising wholeness and completeness, and our potentialities. We are still fighting for bodily autonomy and genital integrity, and this symbolises the right to be who and how we want to be."

Religion
In Judaism, the Talmud contains extensive discussion concerning the status of two types of intersex people in Jewish law; namely, the androgynous, who exhibit both male and female external sexual organs, and the tumtum, who exhibit neither. In the 1970s and 1980s, the treatment of intersex babies started to be discussed in Orthodox Jewish medical halacha by prominent rabbinic leaders, such as Eliezer Waldenberg and Moshe Feinstein.

Sport
Erik Schinegger, Foekje Dillema, Maria José Martínez-Patiño and Santhi Soundarajan were subject to adverse sex verification testing resulting in ineligibility to compete in organised competitive competition. Stanisława Walasiewicz was posthumously ruled ineligible to have competed.The South African middle-distance runner Caster Semenya won gold at the World Championships in the womens 800 metres and won silver in the 2012 Summer Olympics. When Semenya won gold in the World Championships, the International Association of Athletics Federations (IAAF) requested sex verification tests. The results were not released. Semenya was ruled eligible to compete.Katrina Karkazis, Rebecca Jordan-Young, Georgiann Davis and Silvia Camporesi have claimed that IAAF policies on "hyperandrogenism" in female athletes are "significantly flawed", arguing that the policy does not protect against breaches of privacy, requires athletes to undergo unnecessary treatment in order to compete, and intensifies "gender policing", and recommended that athletes be able to compete in accordance with their legally-recognised gender.In April 2014, the BMJ reported that four elite women athletes with XY chromosomes and 5-ARD were subjected to sterilization and "partial clitoridectomies" in order to compete in sport. The authors noted that partial clitoridectomy was "not medically indicated" and "does not relate to real or perceived athletic advantage." Intersex advocates regarded this intervention as "a clearly coercive process". In 2016, the United Nations Special Rapporteur on health, Dainius Pūras, criticized "current and historic" sex verification policies, describing how "a number of athletes have undergone gonadectomy (removal of reproductive organs) and partial clitoridectomy (a form of female genital mutilation) in the absence of symptoms or health issues warranting those procedures."

Biology
The notion of intersex individuals can be understood in the context of sexual system biology that varies across different types of organisms. Most animal species (~95%, including humans) are gonochoric, in which individuals are of either a female or male sex. Hermaphroditic species (some animals and most flowering plants) are represented by individuals that can express both sexes simultaneously or sequentially during their lifetimes. Intersex individuals in a number of gonochoric species, who express both female and male phenotypic characters to some degree, are known to exist at very low prevalences.
Although "hermaphrodite" and "intersex" have been used synonymously in humans, a hermaphrodite is specifically an individual capable of producing female and male gametes. While there are reports of individuals that seemed to have the potential to produce both types of gamete, in more recent years the term hermaphrodite as applied to humans has fallen out of favor, since female and male reproductive functions have not been observed together in the same individual.

Medical
Research in the late 20th century led to a growing medical consensus that diverse intersex bodies are normal, but relatively rare, forms of human biology. Clinician and researcher Milton Diamond stresses the importance of care in the selection of language related to intersex people:

Foremost, we advocate use of the terms "typical", "usual", or "most frequent" where it is more common to use the term "normal." When possible avoid expressions like maldeveloped or undeveloped, errors of development, defective genitals, abnormal, or mistakes of nature. Emphasize that all of these conditions are biologically understandable while they are statistically uncommon.

Medical classifications
Sexual differentiation
The common pathway of sexual differentiation, where a productive human female has an XX chromosome pair, and a productive male has an XY pair, is relevant to the development of intersex conditions.
During fertilization, the sperm adds either an X (female) or a Y (male) chromosome to the X in the ovum. This determines the genetic sex of the embryo. During the first weeks of development, genetic male and female fetuses are "anatomically indistinguishable", with primitive gonads beginning to develop during approximately the sixth week of gestation. The gonads, in a bipotential state, may develop into either testes (the male gonads) or ovaries (the female gonads), depending on the consequent events. Up until and including the seventh week, genetically female and genetically male fetuses appear identical.
At around eight weeks of gestation, the gonads of an XY embryo differentiate into functional testes, secreting testosterone. Ovarian differentiation, for XX embryos, does not occur until approximately week 12 of gestation. In typical female differentiation, the Müllerian duct system develops into the uterus, Fallopian tubes, and inner third of the vagina.
In males, the Müllerian duct-inhibiting hormone MIH causes this duct system to regress. Next, androgens cause the development of the Wolffian duct system, which develops into the vas deferens, seminal vesicles, and ejaculatory ducts.
By birth, the typical fetus has been completely sexed male or female, meaning that the genetic sex (XY-male or XX-female) corresponds with the phenotypical sex; that is to say, genetic sex corresponds with internal and external gonads, and external appearance of the genitals.

Signs
There are a variety of symptoms that can occur. Ambiguous genitalia is the most common sign. There can be micropenis, clitoromegaly, partial labial fusion, electrolyte abnormalities, delayed or absent puberty, unexpected changes at puberty, hypospadias, labial or inguinal (groin) masses (which may turn out to be testes) in girls and undescended testes (which may turn out to be ovaries) in boys.

Ambiguous genitalia
Ambiguous genitalia may appear as a large clitoris or as a small penis.

Because there is variation in all of the processes of the development of the sex organs, a child can be born with a sexual anatomy that is typically female or feminine in appearance with a larger-than-average clitoris (clitoral hypertrophy) or typically male or masculine in appearance with a smaller-than-average penis that is open along the underside. The appearance may be quite ambiguous, describable as female genitals with a very large clitoris and partially fused labia, or as male genitals with a very small penis, completely open along the midline ("hypospadic"), and empty scrotum. Fertility is variable.

Measurement systems for ambiguous genitalia
The orchidometer is a medical instrument to measure the volume of the testicles. It was developed by Swiss pediatric endocrinologist Andrea Prader. The Prader scale and Quigley scale are visual rating systems that measure genital appearance. These measurement systems were satirized in the Phall-O-Meter, created by the (now defunct) Intersex Society of North America.

Other signs
In order to help in classification, methods other than a genitalia inspection can be performed. For instance, a karyotype display of a tissue sample may determine which of the causes of intersex is prevalent in the case. Additionally, electrolyte tests, endoscopic exam, ultrasound and hormone stimulation tests can be done.

Causes
Intersex can be divided into four categories which are: 46, XX intersex; 46, XY intersex; true gonadal intersex; and complex or undetermined intersex.

46, XX intersex
This condition used to be called "female pseudohermaphroditism". Persons with this condition have female internal genitalia and karyotype (XX) and various degree of external genitalia virilization. External genitalia is masculinized congenitally when female fetus is exposed to excess androgenic environment. Hence, the chromosome of the person is of a woman, the ovaries of a woman, but external genitals that appear like a male. The labia fuse, and the clitoris enlarges to appear like a penis. The causes of this can be male hormones taken during pregnancy, congenital adrenal hyperplasia, male-hormone-producing tumors in the mother and aromatase deficiency.

46, XY intersex
This condition used to be called "male pseudohermaphroditism". This is defined as incomplete masculinization of the external genitalia. Thus, the person has the chromosomes of a man, but the external genitals are incompletely formed, ambiguous, or clearly female. This condition is also called 46, XY with undervirilization. 46, XY intersex has many possible causes, which can be problems with the testes and testosterone formation. Also, there can be problems with using testosterone. Some people lack the enzyme needed to convert testosterone to dihydrotestosterone, which is a cause of 5-alpha-reductase deficiency. Androgen insensitivity syndrome is the most common cause of 46, XY intersex.

True gonadal intersex
This condition used to be called "true hermaphroditism". This is defined as having asymmetrical gonads with ovarian and testicular differentiation on either sides separately or combined as ovotestis. In most cases, the cause of this condition is unknown.

Complex or undetermined intersex
This is the condition of having any chromosome configurations rather than 46, XX or 46, XY intersex. This condition does not result in an imbalance between internal and external genitalia. However, there may be problems with sex hormone levels, overall sexual development, and altered numbers of sex chromosomes.

Conditions
There are a variety of opinions on what conditions or traits are and are not intersex, dependent on the definition of intersex that is used. Current human rights based definitions stress a broad diversity of sex characteristics that differ from expectations for male or female bodies. During 2015, the Council of Europe, the European Union Agency for Fundamental Rights and Inter-American Commission on Human Rights have called for a review of medical classifications on the basis that they presently impede enjoyment of the right to health; the Council of Europe expressed concern that "the gap between the expectations of human rights organisations of intersex people and the development of medical classifications has possibly widened over the past decade".

Medical interventions
Rationales
Medical interventions take place to address physical health concerns and psychosocial risks. Both types of rationale are the subject of debate, particularly as the consequences of surgical (and many hormonal) interventions are lifelong and irreversible. Questions regarding physical health include accurately assessing risk levels, necessity, and timing. Psychosocial rationales are particularly susceptible to questions of necessity as they reflect social and cultural concerns.
There remains no clinical consensus about an evidence base, surgical timing, necessity, type of surgical intervention, and degree of difference warranting intervention. Such surgeries are the subject of significant contention due to consequences that include trauma, impact on sexual function and sensation, and violation of rights to physical and mental integrity. This includes community activism, and multiple reports by international human rights and health institutions and national ethics bodies.In the cases where gonads may pose a cancer risk, as in some cases of androgen insensitivity syndrome, concern has been expressed that treatment rationales and decision-making regarding cancer risk may encapsulate decisions around a desire for surgical "normalization".

Types
Feminizing and masculinizing surgeries: Surgical procedures depend on the diagnosis, and there is often a concern as to whether surgery should be performed at all. Typically, surgery is performed shortly after birth. Defenders of the practice argue that individuals must be clearly identified as male or female for them to function socially and develop "normally". Psychosocial reasons are often stated. This is criticised by many human rights institutions, and authors. Unlike other aesthetic surgical procedures performed on infants, such as corrective surgery for a cleft lip, genital surgery may lead to negative consequences for sexual functioning in later life, or feelings of freakishness and unacceptability.
Hormone treatment: There is widespread evidence of prenatal testing and hormone treatment to prevent or eliminate intersex traits, associated also with the problematization of sexual orientation and gender non-conformity.
Psychosocial support: All stakeholders support psychosocial support. A joint international statement by participants at the Third International Intersex Forum in 2013 sought, amongst other demands: "Recognition that medicalization and stigmatisation of intersex people result in significant trauma and mental health concerns. In view of ensuring the bodily integrity and well-being of intersex people, autonomous non-pathologising psycho-social and peer support be available to intersex people throughout their life (as self-required), as well as to parents and/or care providers."
Genetic selection and terminations: The ethics of preimplantation genetic diagnosis to select against intersex traits was the subject of 11 papers in the October 2013 issue of the American Journal of Bioethics. There is widespread evidence of pregnancy terminations arising from prenatal testing, as well as prenatal hormone treatment to prevent intersex traits. Behrmann and Ravitsky find social concepts of sex, gender and sexual orientation to be "intertwined on many levels. Parental choice against intersex may thus conceal biases against same-sex attractedness and gender nonconformity."
Medical display. Photographs of intersex childrens genitalia are circulated in medical communities for documentary purposes, and individuals with intersex traits may be subjected to repeated genital examinations and display to medical teams. Problems associated with experiences of medical photography of intersex children have been discussed along with their ethics, control and usage. "The experience of being photographed has exemplified for many people with intersex conditions the powerlessness and humiliation felt during medical investigations and interventions".
Gender dysphoria: The DSM-5 included a change from using gender identity disorder to gender dysphoria. This revised code now specifically includes intersex people who do not identify with their sex assigned at birth and experience clinically significant distress or impairment, using the language of disorders of sex development.

See also
Intersex Awareness Day
Intersex people and military service
Sexual differentiation in humans
Gynandromorphism
Endosex
True hermaphroditism
Androgyny

References
Bibliography
Asia Pacific Forum of National Human Rights Institutions (June 2016). Promoting and Protecting Human Rights in relation to Sexual Orientation, Gender Identity and Sex Characteristics. ISBN 978-0-9942513-7-4.
Blackless, Melanie; Charuvastra, Anthony; Derryck, Amanda; Fausto-Sterling, Anne; Lauzanne, Karl; Lee, Ellen (2000). "How sexually dimorphic are we? Review and synthesis". Am J Hum Biol. 12 (2): 151–166. doi:10.1002/(SICI)1520-6300(200003/04)12:2<151::AID-AJHB1>3.0.CO;2-F. PMID 11534012. S2CID 453278.
Council of Europe; Commissioner for Human Rights (April 2015), Human rights and intersex people, Issue Paper
Davis, Georgiann (2015). Contesting Intersex, The Dubious Diagnosis. NYU Press. New York. ISBN 978-1-4798-3786-1.
Elders, M Joycelyn; Satcher, David; Carmona, Richard (June 2017). "Re-Thinking Genital Surgeries on Intersex Infants" (PDF). Palm Center.
Fausto-Sterling, Anne (2000). Sexing the Body: Gender Politics and the Construction of Sexuality. Basic Books. ISBN 978-0-465-07714-4.
Ghattas, Dan Christian; Heinrich-Böll-Stiftung (2013). Human Rights between the Sexes: A preliminary study on the life situations of inter*individuals. Berlin: Heinrich-Böll-Stiftung. ISBN 978-3-86928-107-0.
Holmes, Morgan, ed. (2009). Critical intersex. Ashgate Publishing. Queer interventions. Burlington, VT. ISBN 978-0-7546-7311-8.
Hughes, I A; Houk, C; Ahmed, S F; Lee, P A; LWPES1/ESPE2 Consensus Group (June 2005). "Consensus statement on management of intersex disorders". Archives of Disease in Childhood. 91 (7): 554–563. doi:10.1136/adc.2006.098319. ISSN 0003-9888. PMC 2082839. PMID 16624884.
Human Rights Commission of the City and County of San Francisco; de María Arana, Marcus (2005). A Human Rights Investigation Into The Medical "Normalization" Of Intersex People. San Francisco.
Human Rights Watch; interACT (July 2017). I Want to Be Like Nature Made Me. ISBN 978-1-62313-502-7.
Jones, Tiffany; Hart, Bonnie; Carpenter, Morgan; Ansara, Gavi; Leonard, William; Lucke, Jayne (2016). Intersex: Stories and Statistics from Australia (PDF). Cambridge, UK: Open Book Publishers. ISBN 978-1-78374-208-0. Archived from the original (PDF) on 27 May 2018. Retrieved 2 February 2016.
Jones, Tiffany (2018). "Intersex Studies: A Systematic Review of International Health Literature". SAGE Open. 2018 (1): 1–22. doi:10.1177/2158244017745577.
Karkazis, Katrina (2008). Fixing Sex: Intersex, Medical Authority, and Lived Experience. Duke University Press. ISBN 978-0-8223-4318-9.
Lee, Peter A.; Nordenström, Anna; Houk, Christopher P.; Ahmed, S. Faisal; Auchus, Richard; Baratz, Arlene; Baratz Dalke, Katharine; Liao, Lih-Mei; Lin-Su, Karen; Looijenga, Leendert H.J.; Mazur, Tom; Meyer-Bahlburg, Heino F.L.; Mouriquand, Pierre; Quigley, Charmian A.; Sandberg, David E.; Vilain, Eric; Witchel, Selma; and the Global DSD Update Consortium (28 January 2016). "Global Disorders of Sex Development Update since 2006: Perceptions, Approach and Care". Hormone Research in Paediatrics. 85 (3): 158–180. doi:10.1159/000442975. ISSN 1663-2818. PMID 26820577.
National Advisory Commission on Biomedical Ethics, Switzerland (November 2012). On the management of differences of sex development. Ethical issues relating to "intersexuality".Opinion No. 20/2012 (PDF). 2012. Berne. Archived from the original (PDF) on 23 April 2015. Retrieved 20 October 2018.
Organisation Intersex International Australia; Carpenter, Morgan (April 2014). "Submission on the Review of Part B of the Ethical Guidelines for the Use of Assisted Reproductive Technology in Clinical Practice and Research, 2007". Sydney. Archived from the original on 6 October 2014. Retrieved 6 May 2014.
Regmi, Esan (2016). Stories of Intersex People from Nepal. Kathmandu. Archived from the original on 28 July 2017. Retrieved 19 March 2021.
Senate of Australia; Community Affairs References Committee (2013). Involuntary or coerced sterilisation of intersex people in Australia. Canberra. ISBN 978-1-74229-917-4.
Tamar-Mattis, Anne (2014). "Medical Treatment of People with Intersex Conditions as Torture and Cruel, Inhuman, or Degrading Treatment or Punishment".  In Center for Human Rights & Humanitarian Law; Washington College of Law (eds.). Torture in Healthcare Settings: Reflections on the Special Rapporteur on Tortures 2013 Thematic Report. Washington, DC. pp </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Lissencephaly and can you explain it in depth? [/INST] Lissencephaly (, meaning "smooth brain") is a set of rare brain disorders whereby the whole or parts of the surface of the brain appear smooth. It is caused by defective neuronal migration during the 12th to 24th weeks of gestation resulting in a lack of development of brain folds (gyri) and grooves (sulci). It is a form of cephalic disorder. Terms such as agyria (no gyri) and pachygyria (broad gyri) are used to describe the appearance of the surface of the brain.
Children with lissencephaly generally have significant developmental delays, but these vary greatly from child to child depending on the degree of brain malformation and seizure control. Life expectancy can be shortened, generally due to respiratory problems.

Symptoms and signs
Affected children display severe psychomotor impairment, failure to thrive, seizures, and muscle spasticity or hypotonia. Other symptoms of the disorder may include unusual facial appearance, difficulty swallowing, and anomalies of the hands, fingers, or toes.
Symptoms of lissencephaly are detected via ultrasound at about twenty-three weeks and require confirmation from a prenatal MRI. It is characterised by absence or reduction of the sulci and gyri of the cerebral surface and a thickened cortex.There are anatomical symptoms that differ across the two main types of lissencephaly, Classical (Type I) and Cobble Stone (Type 2). In Classical lissencephaly the cortex becomes thickened and can be identified by four layers of the cerebral cortex rather than six.Cobblestone lissencephaly is named after the pebbled or cobblestone appearance of the cortical surface. This uneven cortical surface is due to incomplete organogenesis which leads to no distinguishable layers in the cerebral cortex. Cobblestone lissencephaly shows a reduction and abnormalities in the grey matter of the cerebral cortex.

Causes
Causes of lissencephaly can include viral infections of the uterus or the fetus during the first trimester, or insufficient blood supply to the fetal brain early in pregnancy. There are also a number of genetic causes of lissencephaly, including mutation of the reelin gene (on chromosome 7), as well as other genes on the X chromosome and on chromosome 17. Genetic counseling is usually offered if there is a risk of lissencephaly, coupled with genetic testing.

Neural migration
Folding of the cerebral cortex is important in the development of overall brain function and cognitive abilities. Neuronal migration is the process by which neurons migrate to the final position in the brain during the development of the nervous system. This development of the nervous system occurs between 12 and 16 weeks of gestation. The neurons are created at the ventricular zone. The neurons then extend along the radial glia to reach the cortical zone. It is the disruption of the radial and tangential migration that causes reduced or absence gyri that is known as lissencephaly.The lack of gyri causing a smooth appearance of the cerebral cortex is due to abnormal neuronal migration in the developmental stages of the nervous system. The cause of lissencephaly has been linked to both genetic and non-genetic factors. Three main types of lissencephaly have been identified and although all types display the similar symptoms the pathogenesis of each type varies.The genes associated with lissencephaly are still being discovered; however, due to advances in genetics individual genes are being identified as the cause of lissencephaly. Mutations in LIS1, DCX (doublecortin), ARX(aristaless related homeobox), RELN have all been identified to cause lissencephaly. Viral infections can also cause lissencephaly.The known genetic and viral causes are listed below:

LIS1
LIS1 (also known as PAFAH1B1) is the most widely studied. LIS1 is located on chromosome 17p13.3. LIS1 is integral in regulating the motor protein dynein which plays an important role in the movement of neuronal nuclei along microtubules. The mutation or deletion involving LIS1 is associated with both Isolated Lissencephaly Syndrome and Miller–Dieker syndrome. Miller-Dieker syndrome however, has additional deletions of adjacent genes on chromosome 17 causing facial and other congenital abnormalities and defects. This mutation full or deletion of chromosome 17p13.3 leads to inadequate neuronal migration due to LIS1 encoding for an enzyme that interacts with the microtubule protein dynein. LIS1 mutation or deletion is not inherited from a parent and thus recurrence is unlikely.A Chinese family with an autosomal dominant inheritance pattern and a mutation in this gene has been reported.

DCX
DCX or doublecortin encodes for the doublecortin protein which is similar to LIS1 as it encodes a microtubule associated protein that is related to microtubule function and transport in developing neuronal processes. DCX mutation causes the disorganisation of neocortical layering in the cerebral cortex leading to a reduced folding. DCX is localised to the X chromosome and thus this mutation may be inherited however it still can appear randomly. As it is an X chromosome linked abnormality males who inherit the gene are more likely to be severely affected. Females who inherit the DCX mutation have a more mild version of the syndrome.

ARX
The ARX gene encodes for the aristaless related homeobox genes which are active in the early embryonic development to control formation of many tissues and structure. ARX is involved in the development of the embryonic forebrain, migration and communication of neurons as well as migration and proliferation of interneurons. As ARX is expressed in the ganglionic eminences and the neocortical ventricular zone it can affect both radial and tangential migration. Similar to DCX, ARX is an X chromosome linked gene and is linked with other symptoms such as absence of portions of the brain, abnormal genitalia and severe epilepsy.

RELN
Reelin (RELN) is an extracellular matrix glycoproteins that is secreted to help with the regulation of neuronal migration. Lack of RELN in mice has shown deficiencies in migrating neurons. In reported cases, lissencephaly caused by RELN deficiency has been more severe in anterior brain regions with a very small cerebellum.

Viral infection
Lissencephaly has been recorded to have been caused by viruses and insufficient blood supply to the developing fetal brain. Cytomegalovirus (CMV) is a herpes related virus that can cause congenital defects. CMV has a high affinity for the developing germinal matrix of the brain. The severity of the infection is proportional to the time in gestation that the fetus was infected. It is early infection that leads to lissencephaly. This is because early infection disrupts the migration and development of neurons.

Diagnosis
The diagnosis of lissencephaly is usually made at birth or soon after by ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI). However, these results should be interpreted cautiously since even experienced radiologists can misdiagnose polymicrogyria, a different developmental malformation of the brain, as lissencephaly.
Before birth, complex ultrasounds performed routinely during pregnancy may indicate the presence of a cerebral abnormality, but this method of diagnosis should be complemented by other methods, such as genetic studies and NMR, and the examination is not recommended as part of routine ultrasound examinations, unless family medical history or other reasons for suspecting brain malformation are present. The earliest point during gestation when it is possible to observe abnormal development of the brain surface is approximately in week 20, although ultrasound examinations in week 25–30 are more common. Up to this time, the fetal brain normally has a smooth appearance. If lissencephaly is suspected, chorionic villus sampling can test for some lissencephaly variants, but only those with a known genetic mutation.

Classification
The spectrum of lissencephaly is only now becoming more defined as neuroimaging and genetics have provided more insights into migration disorders. There are around 20 types of lissencephaly that make up the spectrum. Other causes which have not yet been identified are likely as well.
Different systems for classifying lissencephaly exist. One major distinction is "classic" (type I) vs. "cobblestone" (type II), but some systems add additional forms that fit into neither of these categories.
Some types of lissencephaly are described below (OMIM numbers are included where available):

Treatment
Treatment for those with lissencephaly is symptomatic and depends on the severity and locations of the brain malformations. Treatment is tailored towards the symptoms of the individual. Therapies for lissencephaly are to deal with the symptoms as the syndrome is congenital. Supportive care may be needed to help with comfort and nursing needs. Seizures may be controlled with medication and hydrocephalus may require shunting </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Bardet–Biedl syndrome and can you explain it in depth? [/INST] Bardet–Biedl syndrome (BBS) is a ciliopathic human genetic disorder that produces many effects and affects many body systems. It is characterized by rod/cone dystrophy, polydactyly, central obesity, hypogonadism, and kidney dysfunction in some cases. Historically, slower mental processing has also been considered a principal symptom but is now not regarded as such.

Signs and symptoms
Bardet–Biedl syndrome is a pleiotropic disorder with variable expressivity and a wide range of clinical variability observed both within and between families.  The most common clinical features are rod–cone dystrophy, with childhood-onset night-blindness followed by increasing visual loss; postaxial polydactyly; truncal obesity that manifests during infancy and remains problematic throughout adulthood; varying degrees of learning disabilities; male hypogenitalism and complex female genitourinary malformations; and renal dysfunction, a major cause of morbidity and mortality.There is a wide range of secondary features that are sometimes associated with BBS: 147–148  including: 153–154
Strabismus, cataracts, astigmatism, pigmentary retinopathy, poor visual acuity, low vision, and/or blindness caused by an impaired photoreceptor transport mechanism in the retina.
"Brachydactyly, syndactyly of both the hands and feet is common, as is partial syndactyl (most usually between the second and third toes)"
Polyuria/polydipsia (nephrogenic diabetes insipidus)
Ataxia/poor coordination/imbalance
Mild hypertonia (especially lower limbs)
Diabetes mellitus
Hepatic involvement
Anosmia
Auditory deficiencies
Hirschsprung disease and subsequent bowel obstruction has been described.
Hypertrophy of interventricular septum and left ventricle and dilated cardiomyopathy.
Hypogonadism, kidney failure, urogenital sinuses, ectopic urethra, uterus duplex, septate vagina, and hypoplasia of the uterus, ovaries, and fallopian tubes
Speech disorder/delay
Developmental delay, especially of fine and gross motor skills

Relation to other rare genetic disorders
Findings in genetic research published in 2006 have suggested that a large number of genetic disorders, both genetic syndromes and genetic diseases, that were not previously identified in the medical literature as related, may be, in fact, highly related in the genetypical root cause of the widely varying, phenotypically observed disorders.  BBS is one such syndrome that has now been identified to be caused by defects in the cellular ciliary structure.  Thus, BBS is a ciliopathy </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Thymus hyperplasia and can you explain it in depth? [/INST]  </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Aggressive infantile fibromatosis and can you explain it in depth? [/INST]  </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Pustular psoriasis and can you explain it in depth? [/INST] The term pustular psoriasis is used for a heterogeneous group of diseases that share pustular skin characteristics.

Signs and symptoms
Characteristics may vary according to the subtype of pustular psoriasis. For example, it can be localized, commonly to the hands and feet (localized pustular psoriasis), or generalized with widespread patches appearing randomly on any part of the body (generalized pustular psoriasis). However, all forms of pustular psoriasis share in common the presence of red and tender blotchy skin covered with pustules.Pustular psoriasis can be localized, commonly to the hands and feet (palmoplantar pustulosis), or generalized with widespread patches occurring randomly on any part of the body </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Lipoblastomatosis and can you explain it in depth? [/INST]  </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Transient lingual papillitis and can you explain it in depth? [/INST]  </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Vomiting and can you explain it in depth? [/INST] Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of ones stomach through the mouth and sometimes the nose.Vomiting can be the result of ailments like food poisoning, gastroenteritis, pregnancy, motion sickness, or hangover; or it can be an after effect of diseases such as brain tumors, elevated intracranial pressure, or overexposure to ionizing radiation. The feeling that one is about to vomit is called nausea; it often precedes, but does not always lead to vomiting. Impairment due to alcohol or anesthesia can cause inhalation of vomit, leading to suffocation. In severe cases, where dehydration develops, intravenous fluid may be required. Antiemetics are sometimes necessary to suppress nausea and vomiting. Self-induced vomiting can be a component of an eating disorder such as bulimia, and is itself now classified as an eating disorder on its own, purging disorder.

Complications
Aspiration
Vomiting is dangerous if gastric content enters the respiratory tract. Under normal circumstances the gag reflex and coughing prevent this from occurring; however, these protective reflexes are compromised in persons who are under the influence of certain substances (including alcohol) or even mildly anesthetized. The individual may choke and asphyxiate or develop aspiration pneumonia.

Dehydration and electrolyte imbalance
Prolonged and excessive vomiting depletes the body of water (dehydration), and may alter the electrolyte status. Gastric vomiting leads to the loss of acid (protons) and chloride directly. Combined with the resulting alkaline tide, this leads to hypochloremic metabolic alkalosis (low chloride levels together with high HCO−3 and CO2 and increased blood pH) and often hypokalemia (potassium depletion). The hypokalemia is an indirect result of the kidney compensating for the loss of acid. With the loss of intake of food the individual may eventually become cachectic. A less frequent occurrence results from a vomiting of intestinal contents, including bile acids and HCO−3, which can cause metabolic acidosis.

Mallory–Weiss tear
Repeated or profuse vomiting may cause erosions to the esophagus or small tears in the esophageal mucosa (Mallory–Weiss tear). This may become apparent if fresh red blood is mixed with vomit after several episodes.

Dentistry
Recurrent vomiting, such as observed in bulimia nervosa, may lead to the destruction of the tooth enamel due to the acidity of the vomit. Digestive enzymes can also have a negative effect on oral health, by degrading the tissue of the gums.

Pathophysiology
Receptors on the floor of the fourth ventricle of the brain represent a chemoreceptor trigger zone, known as the area postrema, stimulation of which can lead to vomiting. The area postrema is a circumventricular organ and as such lies outside the blood–brain barrier; it can therefore be stimulated by blood-borne drugs that can stimulate vomiting or inhibit it.There are various sources of input to the vomiting center:

The chemoreceptor trigger zone at the base of the fourth ventricle has numerous dopamine D2 receptors, serotonin 5-HT3 receptors, opioid receptors, acetylcholine receptors, and receptors for substance P. Stimulation of different receptors are involved in different pathways leading to emesis, in the final common pathway substance P appears involved.
The vestibular system, which sends information to the brain via cranial nerve VIII (vestibulocochlear nerve), plays a major role in motion sickness, and is rich in muscarinic receptors and histamine H1 receptors.
The cranial nerve X (vagus nerve) is activated when the pharynx is irritated, leading to a gag reflex.
The vagal and enteric nervous system inputs transmit information regarding the state of the gastrointestinal system. Irritation of the GI mucosa by chemotherapy, radiation, distention, or acute infectious gastroenteritis activates the 5-HT3 receptors of these inputs.
The CNS mediates vomiting that arises from psychiatric disorders and stress from higher brain centers.
The medulla plays an important role for triggering the vomiting act.The vomiting act encompasses three types of outputs initiated by the chemoreceptor trigger zone: Motor, parasympathetic nervous system (PNS), and sympathetic nervous system (SNS). They are as follows:

Increased salivation to protect tooth enamel from stomach acids. (Excessive vomiting leads to dental erosion.) This is part of the PNS output.
The body takes a deep breath to avoid aspirating vomit.
Retroperistalsis starts from the middle of the small intestine and sweeps up digestive tract contents into the stomach, through the relaxed pyloric sphincter.
Intrathoracic pressure lowers (by inspiration against a closed glottis), coupled with an increase in abdominal pressure as the abdominal muscles contract, propels stomach contents into the esophagus as the lower esophageal sphincter relaxes. The stomach itself does not contract in the process of vomiting except for at the angular notch, nor is there any retroperistalsis in the esophagus.
Vomiting is ordinarily preceded by retching.
Vomiting also initiates an SNS response causing both sweating and increased heart rate.

Phases
The vomiting act has two phases. In the retching phase, the abdominal muscles undergo a few rounds of coordinated contractions together with the diaphragm and the muscles used in respiratory inspiration. For this reason, an individual may confuse this phase with an episode of violent hiccups. In this retching phase, nothing has yet been expelled. In the next phase, also termed the expulsive phase, intense pressure is formed in the stomach brought about by enormous shifts in both the diaphragm and the abdomen. These shifts are, in essence, vigorous contractions of these muscles that last for extended periods of time—much longer than a normal period of muscular contraction. The pressure is then suddenly released when the upper esophageal sphincter relaxes resulting in the expulsion of gastric contents. Individuals who do not regularly exercise their abdominal muscles may experience pain in those muscles for a few days. The relief of pressure and the release of endorphins into the bloodstream after the expulsion causes the vomiter to feel better.

Contents
Gastric secretions and likewise vomit are highly acidic. Recent food intake appears in the gastric vomit. Irrespective of the content, vomit tends to be malodorous.The content of the vomitus (vomit) may be of medical interest. Fresh blood in the vomit is termed hematemesis ("blood vomiting"). Altered blood bears resemblance to coffee grounds (as the iron in the blood is oxidized) and, when this matter is identified, the term coffee-ground vomiting is used. Bile can enter the vomit during subsequent heaves due to duodenal contraction if the vomiting is severe. Fecal vomiting is often a consequence of intestinal obstruction or a gastrocolic fistula and is treated as a warning sign of this potentially serious problem (signum mali ominis).If the vomiting reflex continues for an extended period with no appreciable vomitus, the condition is known as non-productive emesis or "dry heaves", which can be painful and debilitating.
Color of vomitBright red in the vomit suggests bleeding from the esophagus
Dark red vomit with liver-like clots suggests profuse bleeding in the stomach, such as from a perforated ulcer
Coffee-ground-like vomit suggests less severe bleeding in the stomach because the gastric acid has had time to change the composition of the blood
Yellow vomit suggests bile, indicating that the pyloric valve is open and bile is flowing into the stomach from the duodenum (this is more common in older people)

Causes
Vomiting may be due to a large number of causes, and protracted vomiting has a long differential diagnosis.

Digestive tract
Causes in the digestive tract

Gastritis (inflammation of the gastric wall)
Gastroenteritis
Gastroesophageal reflux disease
Celiac disease
Non-celiac gluten sensitivity
Pyloric stenosis (in babies, this typically causes a very forceful "projectile vomiting" and is an indication for urgent surgery)
Bowel obstruction
Overeating (stomach too full)
Acute abdomen and/or peritonitis
Ileus
Food allergies (often in conjunction with hives or swelling)
Cholecystitis, pancreatitis, appendicitis, hepatitis
Food poisoning
In children, it can be caused by an allergic reaction to cows milk proteins (Milk allergy or lactose intolerance)

Sensory system and brain
Causes in the sensory system:
Movement leading to motion sickness (which is caused by overstimulation of the labyrinthine canals of the ear)
Ménières disease
VertigoCauses in the brain:
Concussion
Cerebral hemorrhage
Migraine
Brain tumors, which can cause the chemoreceptors to malfunction
Benign intracranial hypertension and hydrocephalusMetabolic disturbances (these may irritate both the stomach and the parts of the brain that coordinate vomiting):
Hypercalcemia (high calcium levels)
Uremia (urea accumulation, usually due to kidney failure)
Adrenal insufficiency
Hypoglycemia
HyperglycemiaPregnancy:
Hyperemesis, morning sicknessDrug reaction (vomiting may occur as an acute somatic response to):
Alcohol, which can be partially oxidized into acetaldehyde that causes the symptoms of hangover, including nausea, vomiting, shortness of breath, and fast heart rate.
Opioids
Selective serotonin reuptake inhibitors
Many chemotherapy drugs
Some entheogens (such as peyote or ayahuasca)Illness (sometimes colloquially known as "stomach flu"—a broad name that refers to gastric inflammation caused by a range of viruses and bacteria):
Norovirus (formerly Norwalk virus or Norwalk agent)
Swine influenzaPsychiatric/behavioral:

Bulimia nervosa
Purging disorder

Emetics
An emetic, such as syrup of ipecac, is a substance that induces vomiting when administered orally or by injection. An emetic is used medically when a substance has been ingested and must be expelled from the body immediately. (For this reason, many toxic and easily digestible products such as rat poison contain an emetic. This presents no problem for the effectiveness of the rodenticide as rodents are unable to vomit.) Inducing vomiting can remove the substance before it is absorbed into the body.
Emetics can be divided into two categories, those which produce their effect by acting on the vomiting center in the medulla, and those which act directly on the stomach itself. Some emetics, such as ipecac, fall into both categories; they initially act directly on the stomach, while their further and more vigorous effect occurs by stimulation of the medullary center.Salt water and mustard water, which act directly on the stomach, have been used since ancient times as emetics. Care must be taken with salt, as excessive intake can potentially be harmful.Copper sulfate was also used in the past as an emetic. It is now considered too toxic for this use.Hydrogen peroxide is used as an emetic in veterinary practice.

Self-induced
Eating disorders (anorexia nervosa or bulimia nervosa)
To eliminate an ingested poison (some poisons should not be vomited as they may be more toxic when inhaled or aspirated; it is better to ask for help before inducing vomiting)
Some people who engage in binge drinking induce vomiting to make room in their stomachs for more alcohol consumption.
Participants of the Milk challenge typically end up vomiting most of the milk they consume, as proteins in the ingested milk (such as casein) rapidly denature and unravel on contact with gastric acid and protease enzymes, rapidly filling the stomach. Once the stomach becomes full, stretch receptors in the stomach wall trigger signals to vomit to expel any further liquid the participant ingests.
People suffering from nausea may induce vomiting in hopes of feeling better.

Miscellaneous
After surgery (postoperative nausea and vomiting)
Disagreeable sights or disgust, smells, sounds or thoughts (such as decayed matter, others vomit, thinking of vomiting), etc.
Extreme pain, such as an intense headache or myocardial infarction (heart attack)
Extreme emotions
Cyclic vomiting syndrome (a poorly understood condition with attacks of vomiting)
Cannabinoid hyperemesis syndrome (similar to cyclic vomiting syndrome, but has cannabis use as its underlying cause).
High doses of ionizing radiation sometimes trigger a vomit reflex.
Violent fits of coughing, hiccups, or asthma
Anxiety
Depression
Overexertion (doing too much strenuous exercise can lead to vomiting shortly afterwards).
Rumination syndrome, an underdiagnosed and poorly understood disorder that causes patients to regurgitate food shortly after ingestion.

Other types
Projectile vomiting is vomiting that ejects the gastric contents with great force. It is a classic symptom of infantile hypertrophic pyloric stenosis, in which it typically follows feeding and can be so forceful that some material exits through the nose.

Treatment
An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of medications such as opioids and chemotherapy.Antiemetics act by inhibiting the receptor sites associated with emesis. Hence, anticholinergics, antihistamines, dopamine antagonists, serotonin antagonists, and cannabinoids are used as antiemetics.Evidence to support the use of antiemetics for nausea and vomiting among adults in the emergency department is poor. It is unclear if any medication is better than another or better than no active treatment.

Epidemiology
Nausea and/or vomiting are the main complaints in 1.6% of visits to family physicians in Australia.

Society and culture
Herodotus, writing on the culture of the ancient Persians and highlighting the differences with those of the Greeks, notes that to vomit in the presence of others is prohibited among Persians.

Social cues
It is quite common that, when one person vomits, others nearby become nauseated, particularly when smelling the vomit of others, and often to the point of vomiting themselves. It is believed that this is an evolved trait among primates. Many primates in the wild tend to browse for food in small groups. Should one member of the party react adversely to some ingested food, it may be advantageous (in a survival sense) for other members of the party to also vomit </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Mesoblastic nephroma and can you explain it in depth? [/INST] Congenital mesoblastic nephroma, while rare, is the most common kidney neoplasm diagnosed in the first three months of life and accounts for 3-5% of all childhood renal neoplasms. This neoplasm is generally non-aggressive and amenable to surgical removal. However, a readily identifiable subset of these kidney tumors has a more malignant potential and is capable of causing life-threatening metastases. Congenital mesoblastic nephroma was first named as such in 1967 but was recognized decades before this as fetal renal hamartoma or leiomyomatous renal hamartoma.

Presentation
Congenital mesoblastic nephroma typically (76% of cases) presents as an abdominal mass which is detected prenatally (16% of cases) by ultrasound or by clinical inspection (84% of cases) either at birth or by 3.8 years of age (median age ~1 month). The neoplasm shows a slight male preference. Concurrent findings include hypertension (19% of cases), polyhydramnios (i.e. excess of amniotic fluid in the amniotic sac) (15%), hematuria (11%), hypercalcemia (4%), and elevated serum levels of the kidney-secreted, hypertension-inducing enzyme, renin (1%). Congenital anomalies have been reported in 11 patients: 6 with genitourinary anomalies, 2 with gastrointestinal anomalies, 1 with hydrocephalus, and 1 with the Beckwith–Wiedemann syndrome. The vast majority of patients present with localized (i.e. non-metastatic) disease. Most patients disease is classified at presentation as stage I or II (i.e. localized), few patients present with stage III (i.e. locally advanced/infiltrating), and virtually no patients present with stage IV (metastases present or V (i.e. tumors in both kidneys) disease (see staging of renal cancer).

Tumor pathology
Congenital Mesoblastic nephroma is a malignant tumorous growth of the kidneys mesenchyme (i.e. connective tissue cells). Histologic examination of these tumors provides critical information on their prognoses. This examination divides congenital mesoblastic nephroma into three types:

1) The classic type occurs in ~39% of patients. Its tissues show interlaced spindle-shaped smooth muscle cells evidencing low mitotic activity with no evidence of tumor encapsulation; and infiltration into and entrapment of normal kidney tissue.
2) The cellular type occurs in ~42% of patients. Its tissues show densely packed fibrosarcoma-like cells evidencing high rates of mitosis, less infiltration of normal kidney tissue, and multiple areas of hemorrhage and cysts.
3) The mixed type occurs in ~19% of patients. It shows a mixture of the classic and cellular types in different areas of the neoplasm.

Genetics
A study conducted in 1998 found that congenital mesoblastic nephroma tissues taken from some patients contained an acquired mutation, the ETV6-NTRK3 fusion gene. This gene results from a translocation of genetic material from the ETV6 gene located on the short arm (designated p) of chromosome 12 at position p13.2 (i.e. 12p13.2) to the NTRK3 gene located on the long arm (designated q) of chromosome 15 at position q25.3 (i.e. 15q25.3). This ETV6-NTRK3 gene fusion is notated as t(12;15)(p13;q25) and consists of the 5 end of ETV6 fused to the 3 end  of NTRK3. In consequence, the chimeric protein product of this gene lacks ETV6 proteins transcription factor activity while having NTRK3 proteins tyrosine kinase in an unregulated and continuously active form. Either event can drive the malignant growth of cells but in most cases the chimeric proteins tyrosine kinase activity appears responsible for doing so. Based on a limited number of genetic studies (a total of 65 patients), the ETY6-NTRK3 fusion gene appears to occur in most cases of the cellular and some cases of the mixed but no cases of the classical types of congenital mesolastic nephroma. However, a more recent study of 19 patients detected the fused gene in all 8 cases of cellular, 5 of 6 cases of mixed, and 0 of 5 cases of classic mesoblastic nephroma. This suggests that expression of this fused gene may be more common in cellar and mixed mesoblastic nephroma than previously appreciated.Trisomy, i.e. pathological presence of an extra chromosome, also occurs in these neoplasms. Trisomy of chromosome 11 (e.g. trisomy 11) appears to be the most commonly found trisomy in this disease, being detected in 7 of 13 genetically studied cases. Individual case reports have also found trisomy 8 (9 cases), 17 (4 cases), 20 (4 cases), 7 (3 cases), 10 (3 cases), 18 (2 cases), 2 (2 cases), and 9 (2 cases) associated with the disease. The contribution of these trisomies to the development of mesoblastic nephroma is unclear.

Diagnosis
Diagnosis of mesoblastic nephroma and its particular type (i.e. classic, mixed, or cellular) is made by histological examination of tissues obtained at surgery. Besides its histological appearance, various features of this disease aid in making a differential diagnosis that distinguish it from the following childhood neoplasms:

Wilms tumor is the most common childhood kidney neoplasm, representing some 85% of cases. Unlike mesoblastic nephroma, <2% of Wilms tumor patients present at under 3 months of age and most present in patients of >3 years of age. Bilateral kidney tumors, concurrent birth defects, and/or metastatic disease at presentation favor a diagnosis of Wilms tumor.
congenital infantile sarcoma is a rare aggressive sarcoma typically presenting in the lower extremities, head, or neck of infants during their first year of life. The histology, association with the ETV6-NRTK3 fusion gene along with certain chromosome trisomies, and the distribution of markers for cell type (i.e. cyclin D1 and Beta-catenin) within this tumor are the same as those found in cellular mesoblastic nephroma. Mesoblastic nephroma and congenital infantile sarcoma appear to be the same diseases with mesoblastic lymphoma originating in the kidney and congenital infantile sarcoma originating in non-renal tissues.
Rhabdoid tumor, which accounts for 5-10% of childhood kidney neoplasms, occurs predominantly in children from 1 to 2 years of age. Unlike mesoblastic nephroma, rhabdoid tumors may present with tumors in other tissues including in ~13% of cases, the brain. Rhabdoid tumors have a distinctive histology and abnormalities (i.e. loss of heterozygosity, single nucleotide polymorphism, and deletions) in chromosome 22.
Clear cell sarcoma of the kidney, which is responsible for 5-10% of childhood pediatric tumors, occurs predominantly in children from 2 to 3 years of age. Unlike mesoblastic nephroma, clear cell sarcoma of the kidney presents with metastasis, particularly to bone, in 5-6% of cases; it histology is diverse and has been mistaken for mesoblastic nephroma. One chromosomal translocations t,(10;17)(q22;p13), has been repeatedly reported to be associated with clear cell sarcoma of the kidney.
Infantile myofibromatosis is a fibrous tumor of infancy and childhood most commonly presenting during the first 2 years of life as a single subcutaneous nodule of the head and neck region or less commonly as multiple lesions of skin, muscle, bone, and in ~33% of these latter cases, visceral organs. All of these lesions have an excellent prognosis and can regress spontaneously except for those in which there is visceral involvement where the prognosis is poor. While infantile myofibromatosis and classic mesoblastic nephroma have been suggested to be the same diseases because of their very similar histology, studies on the distribution of cell-type markers (i.e. cyclin D1 and Beta-catenin) indicate that they have different cellular origins.

Treatment
Based on a survey of >800, surgical removal of the entire involved kidney plus the peri-renal fat appeared curative for the majority of all types of mesoblastic nephroma; the patient overall survival rate was 94%. Of the 4% of non-survivors, half were due to surgical or chemotherapeutic treatments. Another 4% of these patients suffered relapses, primarily in the local area of surgery rare cases of relapse due to lung or bone metastasis.. About 60% of these recurrent cases had a complete remission following further treatment. Recurrent disease was treated with a second surgery, radiation, and/or chemotherapy that often vincristine and actinomycin treatment </s>


<s> [INST] <<SYS>> You are a responsible assistant committed to providing accurate and helpful responses. Avoid sharing harmful or biased content. Clarify any unclear or incorrect questions rather than providing false or misleading information. <</SYS>> What is Conjunctivitis and can you explain it in depth? [/INST] Conjunctivitis, also known as pink eye, is inflammation of the outermost layer of the white part of the eye and the inner surface of the eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness, or itchiness may occur. The affected eye may have increased tears or be "stuck shut" in the morning. Swelling of the white part of the eye may also occur. Itching is more common in cases due to allergies. Conjunctivitis can affect one or both eyes.The most common infectious causes are viral followed by bacterial. The viral infection may occur along with other symptoms of a common cold. Both viral and bacterial cases are easily spread between people. Allergies to pollen or animal hair are also a common cause. Diagnosis is often based on signs and symptoms. Occasionally, a sample of the discharge is sent for culture.Prevention is partly by handwashing. Treatment depends on the underlying cause. In the majority of viral cases, there is no specific treatment. Most cases due to a bacterial infection also resolve without treatment; however, antibiotics can shorten the illness. People who wear contact lenses and those whose infection is caused by gonorrhea or chlamydia should be treated. Allergic cases can be treated with antihistamines or mast cell inhibitor drops.About 3 to 6 million people get conjunctivitis each year in the United States. In adults, viral causes are more common, while in children, bacterial causes are more common. Typically, people get better in one or two weeks. If visual loss, significant pain, sensitivity to light, signs of herpes, or if symptoms do not improve after a week, further diagnosis and treatment may be required. Conjunctivitis in a newborn, known as neonatal conjunctivitis, may also require specific treatment.

Signs and symptoms
Red eye, swelling of the conjunctiva, and watering of the eyes are symptoms common to all forms of conjunctivitis. However, the pupils should be normally reactive, and the visual acuity normal.
Conjunctivitis is identified by inflammation of the conjunctiva, manifested by irritation and redness. Examination using a slit lamp (biomicroscope) may improve diagnostic accuracy. Examination of the palpebral conjunctiva, that overlying the inner aspects of the eyelids, is usually more diagnostic than examination of the bulbal conjunctiva, that overlying the sclera.

Viral
Between 65% and 90% of cases of viral conjunctivitis are caused by adenoviruses.
Viral conjunctivitis is often associated with an infection of the upper respiratory tract, a common cold, or a sore throat. Its symptoms include excessive watering and itching. The infection usually begins in one eye but may spread easily to the other eye.
Viral conjunctivitis manifests as a fine, diffuse pinkness of the conjunctiva which may be mistaken for iritis, but corroborative signs on microscopy, particularly numerous lymphoid follicles on the tarsal conjunctiva, and sometimes a punctate keratitis are seen.

Allergic
Allergic conjunctivitis is inflammation of the conjunctiva due to allergy. The specific allergens may differ among patients. Symptoms result from the release of histamine and other active substances by mast cells, and consist of redness (mainly due to vasodilation of the peripheral small blood vessels), swelling of the conjunctiva, itching, and increased production of tears.

Bacterial
Bacterial conjunctivitis causes the rapid onset of conjunctival redness, swelling of the eyelid, and a sticky discharge.  Typically, symptoms develop first in one eye, but may spread to the other eye within 2–5 days.  Conjunctivitis due to common pus-producing bacteria causes marked grittiness or irritation and a stringy, opaque, greyish or yellowish discharge that may cause the lids to stick together, especially after sleep.  Severe crusting of the infected eye and the surrounding skin may also occur.  The gritty or scratchy feeling is sometimes localized enough that patients may insist that they have a foreign body in the eye.Common bacteria responsible for nonacute bacterial conjunctivitis are Staphylococcus, Streptococcus, and Haemophilus species. Less commonly, Chlamydia spp. may be the cause.

Bacteria such as Chlamydia trachomatis or Moraxella spp. can cause a nonexudative but persistent conjunctivitis without much redness.  Bacterial conjunctivitis may cause the production of membranes or pseudomembranes that cover the conjunctiva.  Pseudomembranes consist of a combination of inflammatory cells and exudates and adhere loosely to the conjunctiva, while true membranes are more tightly adherent and cannot be easily peeled away.  Cases of bacterial conjunctivitis that involve the production of membranes or pseudomembranes are associated with Neisseria gonorrhoeae, β-hemolytic streptococci, and Corynebacterium diphtheriae.  C. diphtheriae causes membrane formation in conjunctiva of unimmunized children.

Chemical
Chemical eye injury may result when an acidic or alkaline substance gets in the eye. Alkali burns are typically worse than acidic burns. Mild burns produce conjunctivitis, while more severe burns may cause the cornea to turn white. Litmus paper may be used to test for chemical causes. When a chemical cause has been confirmed, the eye or eyes should be flushed until the pH is in the range 6–8. Anaesthetic eye drops can be used to decrease the pain.Irritant or toxic conjunctivitis is primarily marked by redness. If due to a chemical splash, it is often present in only the lower conjunctival sac.  With some chemicals, above all with caustic alkalis such as sodium hydroxide,  necrosis of the conjunctiva marked by a deceptively white eye due to vascular closure may occur, followed by sloughing off of the dead epithelium. A slit lamp examination is likely to show evidence of anterior uveitis.

Other
Inclusion conjunctivitis of the newborn  is a conjunctivitis that may be caused by the bacterium Chlamydia trachomatis, and may lead to acute, purulent conjunctivitis. However, it is usually self-healing.

Causes
Infective conjunctivitis is most commonly caused by a virus. Bacterial infections, allergies, other irritants, and dryness are also common causes. Both bacterial and viral infections are contagious, passing from person to person or spread through contaminated objects or water. Contact with contaminated fingers is a common cause of conjunctivitis. Bacteria may also reach the conjunctiva from the edges of the eyelids and the surrounding skin, from the nasopharynx, from infected eye drops or contact lenses, from the genitals or the bloodstream. Infection by human adenovirus accounts for 65% to 90% of cases of viral conjunctivitis.

Viral
Adenoviruses are the most common cause of viral conjunctivitis (adenoviral keratoconjunctivitis). Herpetic keratoconjunctivitis, caused by herpes simplex viruses, can be serious and requires treatment with aciclovir. Acute hemorrhagic conjunctivitis is a highly contagious disease caused by one of two enteroviruses, enterovirus 70 and coxsackievirus A24. These were first identified in an outbreak in Ghana in 1969, and have spread worldwide since then, causing several epidemics.

Bacterial
The most common causes of acute bacterial conjunctivitis are Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae. Though very rare, hyperacute cases are usually caused by Neisseria gonorrhoeae or Neisseria meningitidis.  Chronic cases of bacterial conjunctivitis are those lasting longer than 3 weeks, and are typically caused by S. aureus, Moraxella lacunata, or Gram-negative enteric flora.

Allergic
Conjunctivitis may also be caused by allergens such as pollen, perfumes, cosmetics, smoke, dust mites, Balsam of Peru, or eye drops. The most frequent cause of conjunctivitis is allergic conjunctivitis and it affects 15% to 40% of the population. Allergic conjunctivitis accounts for 15% of eye related primary care consultations; most including seasonal exposures in the spring and summer or perpetual conditions.

Other
Computer vision syndrome
Dry eye syndrome
Reactive arthritis: Conjunctivitis is part of the triad of reactive arthritis, which is thought to be caused by autoimmune cross-reactivity following certain bacterial infections. Reactive arthritis is highly associated with HLA-B27. Conjunctivitis is associated with the autoimmune disease relapsing polychondritis.

Diagnosis
Cultures are not often taken or needed as most cases resolve either with time or typical antibiotics.  If bacterial conjunctivitis is suspected, but no response to topical antibiotics is seen, swabs for bacterial culture should be taken and tested. Viral culture may be appropriate in epidemic case clusters.A patch test is used to identify the causative allergen in allergic conjunctivitis.Although conjunctival scrapes for cytology can be useful in detecting chlamydial and fungal infections, allergy, and dysplasia, they are rarely done because of the cost and the general dearth of laboratory staff experienced in handling ocular specimens.  Conjunctival incisional biopsy is occasionally done when granulomatous diseases (e.g., sarcoidosis) or dysplasia are suspected.

Classification
Conjunctivitis may be classified either by cause or by extent of the inflamed area.

Causes
Allergy
Bacteria
Viruses
Chemicals
AutoimmuneNeonatal conjunctivitis is often grouped separately from bacterial conjunctivitis because it is caused by different bacteria than the more common cases of bacterial conjunctivitis.

By extent of involvement
Blepharoconjunctivitis is the dual combination of conjunctivitis with blepharitis (inflammation of the eyelids).
Keratoconjunctivitis is the combination of conjunctivitis and keratitis (corneal inflammation).
Blepharokeratoconjunctivitis is the combination of conjunctivitis with blepharitis and keratitis. It is clinically defined by changes of the lid margin, meibomian gland dysfunction, redness of the eye, conjunctival chemosis and inflammation of the cornea.

Differential diagnosis
Some more serious conditions can present with a red eye, such as infectious keratitis, angle-closure glaucoma, or iritis. These conditions require the urgent attention of an ophthalmologist. Signs of such conditions include decreased vision, significantly increased sensitivity to light, inability to keep the eye open, a pupil that does not respond to light, or a severe headache with nausea. Fluctuating blurring is common, due to tearing and mucoid discharge.  Mild photophobia is common.  However, if any of these symptoms is prominent, considering other diseases such as glaucoma, uveitis, keratitis, and even meningitis or carotico-cavernous fistula is important.A more comprehensive differential diagnosis for the red or painful eye includes:
Corneal abrasion
Subconjunctival hemorrhage
Pinguecula
Blepharitis
Dacryocystitis
Keratoconjunctivitis sicca (dry eye)
Keratitis
Herpes simplex
Herpes zoster
Episcleritis - an inflammatory condition that produces a similar appearance to conjunctivitis, but without discharge or tearing
Uveitis
Acute angle-closure glaucoma
Endophthalmitis
Orbital cellulitis

Prevention
The most effective prevention is good hygiene, especially avoiding rubbing the eyes with infected hands. Vaccination against adenovirus, Haemophilus influenzae, pneumococcus, and Neisseria meningitidis is also effective.Povidone-iodine eye solution has been found to prevent neonatal conjunctivitis. It is becoming more commonly used globally because of its low cost.

Management
Conjunctivitis resolves in 65% of cases without treatment, within 2–5 days. The prescription of antibiotics is not necessary in most cases.

Viral
Viral conjunctivitis usually resolves on its own and does not require any specific treatment. Antihistamines (e.g., diphenhydramine) or mast cell stabilizers (e.g., cromolyn) may be used to help with the symptoms. Povidone-iodine has been suggested as a treatment, but as of 2008, evidence to support it was poor.

Allergic
For allergic conjunctivitis, cool water poured over the face with the head inclined downward constricts capillaries, and artificial tears sometimes relieve discomfort in mild cases. In more severe cases, nonsteroidal anti-inflammatory medications and antihistamines may be prescribed. Persistent allergic conjunctivitis may also require topical steroid drops.

Bacterial
Bacterial conjunctivitis usually resolves without treatment. Topical antibiotics may be needed only if no improvement is observed after 3 days. No serious effects were noted either with or without treatment. Because antibiotics do speed healing in bacterial conjunctivitis, their use may be considered. Antibiotics are also recommended for those who wear contact lenses, are immunocompromised, have disease which is thought to be due to chlamydia or gonorrhea, have a fair bit of pain, or have copious discharge. Gonorrheal or chlamydial infections require both oral and topical antibiotics.The choice of antibiotic varies based on the strain or suspected strain of bacteria causing the infection. Fluoroquinolones, sodium sulfacetamide, or trimethoprim/polymyxin may be used, typically for 7–10 days.  Cases of meningococcal conjunctivitis can also be treated with systemic penicillin, as long as the strain is sensitive to penicillin.When investigated as a treatment, povidone-iodine ophthalmic solution has also been observed to have some effectiveness against bacterial and chlamydial conjunctivitis, with a possible role suggested in locations where topical antibiotics are unavailable or costly.

Chemical
Conjunctivitis due to chemicals is treated via irrigation with Ringers lactate or saline solution. Chemical injuries, particularly alkali burns, are medical emergencies, as they can lead to severe scarring and intraocular damage. People with chemically induced conjunctivitis should not touch their eyes to avoid spreading the chemical.

Epidemiology
Conjunctivitis is the most common eye disease. Rates of disease is related to the underlying cause which varies by the age as well as the time of year. Acute conjunctivitis is most frequently found in infants, school-age children and the elderly. The most common cause of infectious conjunctivitis is viral conjunctivitis.It is estimated that acute conjunctivitis affects 6 million people annually in the United States.Some seasonal trends have been observed for the occurrence of different forms of conjunctivitis </s>