Common questions about infectious mononucleosis.

Epstein-Barr is a ubiquitous virus that infects 95% of the world population at some point in life. Although Epstein-Barr virus (EBV) infections are often asymptomatic, some patients present with the clinical syndrome of infectious mononucleosis (IM). The syndrome most commonly occurs between 15 and 24 years of age. It should be suspected in patients presenting with sore throat, fever, tonsillar enlargement, fatigue, lymphadenopathy, pharyngeal inflammation, and palatal petechiae. A heterophile antibody test is the best initial test for diagnosis of EBV infection, with 71% to 90% accuracy for diagnosing IM. However, the test has a 25% false-negative rate in the first week of illness. IM is unlikely if the lymphocyte count is less than 4,000 mm3. The presence of EBV-specific immunoglobulin M antibodies confirms infection, but the test is more costly and results take longer than the heterophile antibody test. Symptomatic relief is the mainstay of treatment. Glucocorticoids and antivirals do not reduce the length or severity of illness. Splenic rupture is an uncommon complication of IM. Because physical activity within the first three weeks of illness may increase the risk of splenic rupture, athletic participation is not recommended during this time. Children are at the highest risk of airway obstruction, which is the most common cause of hospitalization from IM. Patients with immunosuppression are more likely to have fulminant EBV infection.