Epstein-Barr virus infection
Patients with infectious mononucleosis typically present with fever, lymphadenopathy, and pharyngitis. Physical exam should include evaluation for splenomegaly, which may or may not be present with infectious mononucleosis. If present, this warrants limitations on physical activity given the risk of splenic rupture. A peripheral blood smear will show atypical lymphocytes. Transaminases may also be elevated. Many patients who are treated with ampicillin or amoxicillin for presumed bacterial infection before the diagnosis of mononucleosis is made will develop a pruritic maculopapular rash. Rare complications can include splenic rupture.
Acute infection due to the human immunodeficiency virus (HIV primary infection) may present with similar symptoms and should always be considered in the appropriate clinical context.
Symptoms are usually self-limited. Patients usually develop nonspecific heterophile antibodies. Serologies may be positive for IgM antibodies to viral capsid antigen. Viral DNA may also be identified by nucleic acid amplification.
EBV reactivation can lead to oral hairy leukoplakia in immunosuppressed patients (including patients with AIDS). EBV has also been associated with hemophagocytic lymphohistiocytosis.
Chronic active EBV infection is a very rare condition. Patients with this condition have histologic evidence of major organ dysfunction with presence of EBV nucleic acid or proteins in the affected organs.
EBV has been associated with many malignant diseases. In immunocompromised patients, infection can facilitate the development of various lymphoproliferative disorders, including Burkitt lymphoma, Hodgkin lymphoma, oral hairy leukoplakia, primary central nervous system lymphoma, nasopharyngeal carcinoma, and, in transplant patients, post-transplant lymphoproliferative disease.
B27.00 – Gammaherpesviral mononucleosis without complication
240530001 – Epstein-Barr virus disease
Differential Diagnosis & Pitfalls
- Primary HIV infection can present with a mononucleosis-like illness.
- Primary cytomegalovirus infection can present with a mononucleosis-like illness and atypical lymphocytes.
- Primary toxoplasmosis can present with a mononucleosis-like illness with peripheral lymphadenopathy and reactive lymphocytes.
- Mumps can be associated with atypical lymphocytes, although the parotid swelling would be atypical for EBV infection.
- Hepatitis A, B, C, D, or E – May have reactive lymphocytes, but jaundice is not typical of primary EBV infection and the liver enzyme elevations in EBV infection are usually more mild.
- Drug reactions can sometimes be associated with atypical lymphocytes.
- Thrush can have a similar appearance to oral hairy leukoplakia, but the white plaque of thrush can be easily scraped off with a tongue depressor.