mononucleosis

Mononucleosis, also known as infectious mononucleosis, is an illness most often caused by Epstein-Barr virus. It presents with fever, sore throat, swollen lymph nodes, and fatigue, and typically affects adolescents and young adults, though it can occur in children.

EBV is a herpesvirus transmitted mainly through saliva and close contact, though contaminated surfaces and shared utensils can also spread the infection. The incubation period is about 4–6 weeks.

Common findings include fever, pharyngitis, posterior cervical lymphadenopathy, and marked fatigue. Splenomegaly and, less commonly, hepatomegaly with mild liver enzyme elevations may occur. Atypical lymphocytes can be seen on blood tests, and a rash may develop if amoxicillin or ampicillin is given during illness.

Diagnosis relies on clinical features and supportive laboratory tests. Heterophile antibody tests (Monospot) are positive in many adolescents and adults; EBV-specific serology (VCA-IgM, VCA-IgG, EBNA) can confirm infection. A complete blood count often shows atypical lymphocytosis.

Treatment is supportive: rest, fluids, and analgesics/antipyretics. There is no proven antiviral therapy. Avoid contact sports or strenuous activity until splenomegaly has resolved to reduce rupture risk. Do not administer ampicillin or amoxicillin if EBV infection is suspected, as a hypersensitivity rash is common. Most people recover in 2–4 weeks, though fatigue can persist longer.

Complications are uncommon but can include splenic rupture, hepatitis, airway obstruction, meningitis or encephalitis, and rare hematologic or neurologic problems. Prevention relies on standard infection-control measures; no vaccine is available. Transmission risk declines as the acute illness resolves.