Infectious mononucleosis in adolescents.

Infectious mononucleosis is a clinical manifestation of primary EBV infection in adolescents, characterized by a triad of clinical, laboratory, and serologic features. The classic signs and symptoms are not seen in every patient; rather, the presentations tend to fit into one of three clinical forms (pharyngeal, glandular, or febrile). Recognizing these syndromes provides a useful framework for anticipating the clinical course, complications, and differential diagnosis. Nonclassic presentations of IM include a wide variety of neurologic abnormalities, thrombocytopenic purpura, and splenic rupture. The laboratory features of IM include absolute lymphocytosis with a large percentage of atypical lymphocytes, and abnormal liver chemistries in 90% of patients. The diagnosis of IM is confirmed serologically, usually with the demonstration of heterophile antibodies; the test can conveniently be performed in office laboratories. If the heterophile antibody test is negative, EBV-specific serologic tests can identify whether the illness is due to primary EBV infection. Once the diagnosis of IM is made, appropriate guidelines for resumption of activity should be provided to patients, especially to those with evidence of splenomegaly. Medical management includes supportive therapy with adequate analgesia. Corticosteroids are indicated for patients with upper airway obstruction; they may be helpful in patients with neurologic, hematologic, or cardiac complications. Acyclovir may prove to be useful, but further studies are needed before its use can be recommended.