Items in AFP with MESH term: Hypothyroidism
Treatment of Hypothyroidism - Article
ABSTRACT: Thyroid disease affects up to 0.5 percent of the population of the United States. Its prevalence is higher in women and the elderly. The management of hypothyroidism focuses on ensuring that patients receive appropriate thyroid hormone replacement therapy and monitoring their response. Hormone replacement should be initiated in a low dosage, especially in the elderly and in patients prone to cardiac problems. The dosage should be increased gradually, and laboratory values should be monitored six to eight weeks after any dosage change. Once a stable dosage is achieved, annual monitoring of the thyroid-stimulating hormone (TSH) level is probably unnecessary, except in older patients. After full replacement of thyroxine (T4) using levothyroxine, the addition of triiodothyronine (T3) in a low dosage may be beneficial in some patients who continue to have mood or memory problems. The management of patients with subclinical hypothyroidism (a high TSH in the presence of normal free T4 and T3 levels) remains controversial. In these patients, physicians should weigh the benefits of replacement (e.g., improved cardiac function) against problems that can accompany the excessive use of levothyroxine (e.g., osteoporosis).
Subclinical Thyroid Disease - Article
ABSTRACT: Subclinical thyroid dysfunction is defined as an abnormal serum thyroid-stimulating hormone level (reference range: 0.45 to 4.50 microU per mL) and free thyroxine and triiodothyronine levels within their reference ranges. The management of subclinical thyroid dysfunction is controversial. The prevalence of subclinical hypothyroidism is about 4 to 8.5 percent, and may be as high as 20 percent in women older than 60 years. Subclinical hyperthyroidism is found in approximately 2 percent of the population. Most national organizations recommend against routine screening of asymptomatic patients, but screening is recommended for high-risk populations. There is good evidence that subclinical hypothyroidism is associated with progression to overt disease. Patients with a serum thyroid-stimulating hormone level greater than 10 microU per mL have a higher incidence of elevated serum low-density lipoprotein cholesterol concentrations; however, evidence is lacking for other associations. There is insufficient evidence that treatment of subclinical hypothyroidism is beneficial. A serum thyroid-stimulating hormone level of less than 0.1 microU per mL is associated with progression to overt hyperthyroidism, atrial fibrillation, reduced bone mineral density, and cardiac dysfunction. There is little evidence that early treatment alters the clinical course.
Thyroiditis - Article
ABSTRACT: Thyroiditis is an inflammation of the thyroid gland that may be painful and tender when caused by infection, radiation, or trauma, or painless when caused by autoimmune conditions, medications, or an idiopathic fibrotic process. The most common forms are Hashimoto's disease, subacute granulomatous thyroiditis, postpartum thyroiditis, subacute lymphocytic thyroiditis, and drug-induced thyroiditis (caused by amiodarone, interferon-alfa, interleukin-2, or lithium). Patients may have euthyroidism, hyperthyroidism, or hypothyroidism, or may evolve from one condition to another over time. Diagnosis is by clinical context and findings, including the presence or absence of pain, tenderness, and autoantibodies. In addition, the degree of radioactive iodine uptake by the gland is reduced in most patients with viral, radiation-induced, traumatic, autoimmune, or drug-induced inflammation of the thyroid. Treatment primarily is directed at symptomatic relief of thyroid pain and tenderness, if present, and restoration of euthyroidism.
Evaluation of Macrocytosis - Article
ABSTRACT: Macrocytosis, generally defined as a mean corpuscular volume greater than 100 fL, is frequently encountered when a complete blood count is performed. The most common etiologies are alcoholism, vitamin B12 and folate deficiencies, and medications. History and physical examination, vitamin B12 level, reticulocyte count, and a peripheral smear are helpful in delineating the underlying cause of macrocytosis. When the peripheral smear indicates megaloblastic anemia (demonstrated by macro-ovalocytes and hyper-segmented neutrophils), vitamin B12 or folate deficiency is the most likely cause. When the peripheral smear is non-megaloblastic, the reticulocyte count helps differentiate between drug or alcohol toxicity and hemolysis or hemorrhage. Of other possible etiologies, hypothyroidism, liver disease, and primary bone marrow dysplasias (including myelodysplasia and myeloproliferative disorders) are some of the more common causes.
Management of Subclinical Hypothyroidism - FPIN's Clinical Inquiries
Subclinical Hypothyroidism - Cochrane for Clinicians
ABSTRACT: Peripheral neuropathy has a variety of systemic, metabolic, and toxic causes. The most common treatable causes include diabetes mellitus, hypothyroidism, and nutritional deficiencies. The diagnosis requires careful clinical assessment, judicious laboratory testing, and electrodiagnostic studies or nerve biopsy if the diagnosis remains unclear. A systematic approach begins with localization of the lesion to the peripheral nerves, identification of the underlying etiology, and exclusion of potentially treatable causes. Initial blood tests should include a complete blood count, comprehensive metabolic profile, and measurement of erythrocyte sedimentation rate and fasting blood glucose, vitamin B12, and thyroid-stimulating hormone levels; specialized tests should be ordered if clinically indicated. Lumbar puncture and cerebrospinal fluid analysis may be helpful in the diagnosis of Guillain-Barré syndrome and chronic inflammatory demyelinating neuropathy. Electrodiagnostic studies, including nerve conduction studies and electromyography, can help in the differentiation of axonal versus demyelinating or mixed neuropathy. Treatment should address the underlying disease process, correct any nutritional deficiencies, and provide symptomatic treatment.
Secondary Causes of Obesity - FPIN's Clinical Inquiries
Hypothyroidism: An Update - Article
ABSTRACT: Hypothyroidism is a clinical disorder commonly encountered by the primary care physician. Untreated hypothyroidism can contribute to hypertension, dyslipidemia, infertility, cognitive impairment, and neuromuscular dysfunction. Data derived from the National Health and Nutrition Examination Survey suggest that about one in 300 persons in the United States has hypothyroidism. The prevalence increases with age, and is higher in females than in males. Hypothyroidism may occur as a result of primary gland failure or insufficient thyroid gland stimulation by the hypothalamus or pituitary gland. Autoimmune thyroid disease is the most common etiology of hypothyroidism in the United States. Clinical symptoms of hypothyroidism are nonspecific and may be subtle, especially in older persons. The best laboratory assessment of thyroid function is a serum thyroid-stimulating hormone test. There is no evidence that screening asymptomatic adults improves outcomes. In the majority of patients, alleviation of symptoms can be accomplished through oral administration of synthetic levothyroxine, and most patients will require lifelong therapy. Combination triiodothyronine/thyroxine therapy has no advantages over thyroxine monotherapy and is not recommended. Among patients with subclinical hypothyroidism, those at greater risk of progressing to clinical disease, and who may be considered for therapy, include patients with thyroid-stimulating hormone levels greater than 10 mIU per L and those who have elevated thyroid peroxidase antibody titers.
Thyroid Disease in Pregnancy - Article
ABSTRACT: Thyroid disease is the second most common endocrine disorder affecting women of reproductive age, and when untreated during pregnancy is associated with an increased risk of miscarriage, placental abruption, hypertensive disorders, and growth restriction. Current guidelines recommend targeted screening of women at high risk, including those with a history of thyroid disease, type 1 diabetes mellitus, or other autoimmune disease; current or past use of thyroid therapy; or a family history of autoimmune thyroid disease. Appropriate management results in improved outcomes, demonstrating the importance of proper diagnosis and treatment. In women with hypothyroidism, levothyroxine is titrated to achieve a goal serum thyroid-stimulating hormone level less than 2.5 mIU per L. The preferred treatment for hyperthyroidism is antithyroid medications, with a goal of maintaining a serum free thyroxine level in the upper one-third of the normal range. Postpartum thyroiditis is the most common form of postpartum thyroid dysfunction and may present as hyper- or hypothyroidism. Symptomatic treatment is recommended for the former; levothyroxine is indicated for the latter in women who are symptomatic, breastfeeding, or who wish to become pregnant.