Sports Sciences Feature: Infectious Mononucleosis
Feb. 1, 2005
Bryan W. Smith, M.D., Ph.D.
Every year it seems like we hear of an ACC basketball player who is stricken with mono and has to miss a substantial portion of the season. By the way it's reported in the media, it might seem that basketball players are predisposed to mono but that is not the case. However, this is as good a time as any to discuss a common disease of teenagers and young adults. For most teens, the disease is a nuisance. For the athlete, if the disease is not properly managed, there are potential complications that can be life-threatening.
Infectious mononucleosis is a viral illness caused most often by the Epstein-Barr virus. Another virus called cytomegalovirus or CMV can produce a mono-like illness in rare cases. The Epstein-Barr virus is typically acquired from infected saliva which requires close personal contact. There is a reason why this condition is commonly referred to as the "kissing disease". After one has become exposed to the virus, it takes one to two months to develop symptoms.
Having taken care of high school and college age individuals the majority of my medical career, I have seen and diagnosed numerous cases of mono. As a doctor, what is clinically fascinating about this disease is the wide variety of presentations. Some individuals may acquire the virus and not have any noticeable symptoms while others may become so ill that they require hospitalization.
The symptoms of mono are quite common and are seldom conclusive to make the diagnosis alone. The most common presentation is that of a 3-5 day prodrome of low grade headache, malaise, fatigue, decreased appetite, and muscle soreness. This is followed by sore throat, moderate fever, chills and sweats, and tender, swollen lymph nodes in the neck. The lymph nodes in the back of the neck particularly stand out. Other symptoms may include cough, rash, nausea, swollen eyelids, joint aches, and abdominal pain. One seldom has all the symptoms and some have more of the less common symptoms and none of the common ones.
Because the symptoms are so varied and the extent of the symptoms can range from mild to severe, persons with mono come to the doctor at different stages of the illness. Some may be very ill or some may just be tired. Laboratory tests can help the doctor in making the proper diagnosis. Usually this results in blood tests and maybe a throat culture. When the patient comes to the doctor dictates which tests are needed.
Why is it important to diagnose mono in the young, healthy adolescent? That's a good question because with most viral illnesses, there is little curative treatment. One just lets the illness run its course and the patient improves. In most cases, mono fits this category in that there is no specific treatment other then rest, fluids, and acetaminophen for fever. If the patient has strep throat in addition to mono, he or she needs antibiotics. The reason it's important to diagnose infectious mononucleosis is because of the potential complications that may develop in the course of the illness. Some of these complications can result in potentially tragic outcomes such as upper airway obstruction from extremely swollen tonsils and adenoids. Many organs are affected during the illness such as the liver, spleen, heart and lungs. While all of these organs are important and each patient is different, the focus on the athlete typically centers on the spleen.
The spleen is located in the upper left abdominal area. It functions as a blood filtering and storage organ. Damage to it could result in massive internal bleeding. Fifty percent of persons who contract mono develop an enlarged spleen or splenomegaly between day 6 to day 21 of the illness. The splenomegaly alone is not a reason for concern. If the enlarged spleen were to rupture either from direct trauma or increased abdominal pressure, then a medical emergency would occur. This would likely require emergency surgery and the patient's life could be in jeopardy depending on the situation. Fortunately, a ruptured spleen is a very rare occurrence.
How does the doctor know the patient has splenomegaly? It's difficult because the degree of illness doesn't completely correspond to the likelihood of having an enlarged spleen. When the patient exactly became ill so as to start the day clock for 21 days is imprecise. In addition, trying to size out a patient's spleen can be next to impossible by physical exam.
Consider the following scenario; you diagnose your one of your starters on the basketball players with mono on March 1. His acute symptoms (sore throat, headache, fever, and fatigue) resolve in five days. Now, (which is unlikely) he feels like he could play. (Most would be too fatigued.) What do you do knowing about the potential to develop splenomegaly?
The issue about how big the spleen can be accurately answered by obtaining an abdominal ultrasound exam. This is a painless, non-invasive, easy to obtain exam that can measure the size of the spleen. If our athlete's spleen is enlarged, the decision is obvious. However, there are some of pitfalls with this test. One, the athlete's spleen may not be enlarged because the size of the athlete's spleen is compared to normative standards which may not be accurate for very large athletes. Second, if the spleen is not enlarged compared to normative standards, it may be enlarged for that athlete if he or she has a small spleen in the normal range. Third, the spleen measurement is only as good as the time it was obtained. One hour, six hours, twenty-four hours, three days later it may change in the 21-day window of time.
To avoid the possibility of a life-threatening complication, doctors restrict the athlete from all physical activity for the 21-day period. The time clock usually starts when the athlete presents to the doctor. The restriction may be longer if the splenomegaly has not resolved or the athlete is too fatigued to participate. Once the athlete feels better after 21 days have passed and there is no concern about splenomegaly, the athlete can be allowed to gradually return to physical activity. Contact sports may be restricted for the first week back. It may take several weeks to be back at full strength depending on the sport and the physical demands. Endurance activities take the longest to recover.
Are there any medications that will speed this recovery process? The answer is no. In some cases, patients need to be placed on a short course of steroids (not the ones that are making the news involving professional athletes) to prevent some complications such as airway obstruction.
How contagious is mono? Not very! As long as one avoids situations where saliva can be passed, one should be fine. Roommates are no more at risk to get mono than the general student population as long as they follow good hygiene. Don't share food or towels. Cover your mouth and nose when coughing and sneezing.
Infectious mononucleosis is a common viral illness that typically affects adolescents. For the athlete, prompt medical assessment and management can keep this infection just a nuisance.