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Infectious Mononucleosis

Adam Stern, PGY IIIUNC Hospitals

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Infectious Mononucleosis

Virology Epstein Barr Virus (EBV)

Herpes Family (linear DNA virus HHV4)

Surrounded by nucleocapsid and glycoproteinenvelope

Also associated w/ nasopharyngeal

carcinoma, Burkitts lymphoma,Hodgkins Disease,B cell lymphoma.

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Infectious Mononuclosis

Epidemiology Worldwide Prevalence of EBV Infections peak in early childhood and late

adolescence/young adulthood. By adulthood , 90% of individuals have

been infected and have antibodies to thevirus.

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Infectious Mononucleosis

TransmissionThe Kissing Disease

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Infectious Mononucleosis

Pathogenesis EBV infects the epithelium of the

oropharynx and salivary glands.

Lymphocytes in the tonsilar crypts aredirectly infected -> BLOODSTREAM.

Infected B cells and activated T cells

proliferate and expand. Polyclonal B cells produce antibodies tohost and viral proteins.

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Infectious Mononucleosis

Pathogenesis

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Infectious Mononucleosis

Pathogenesis Memory B cells (not epithelial cells) are

reservoir for EBV. EBV receptor is CD21 (found on B cell

surface) Cellular immunity (suppressor T cells, NK

cells, cytotoxic T cells) more important thanhumoral immunity in controlling infection

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Infectious Mononucleosis

Pathogenesis

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Infectious Mononucleosis

Signs & Symptoms Incubation in adults 4-6 wks Prodrome (1-2 weeks before illness)

Fatigue, Malaise, Myalgias Symptoms Sore throat, Malaise, Headache, Abdominal Pain,

Nausea/Vomiting, Chills

Signs Lymphadenopathy, Fever, Pharyngitis, Splenomegay,

Hepatomegaly, Rash, Periorbital Edema, PalatalEnanthem, Jaundice.

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Infectious Mononucleosis

Diagnosis Lymphocytosis (>50% Lymphs) Atypical Lymphocytes (>10%, mostly CD8+ T

cells) +Heterophile Antibodies (human serumagglutinates the erythrocytes of non-humanspecies) (75% sens, 90% spec) (FP = lymphoma,

CTD, viral hepatitis, malaria) Monospot -rapid agglutination assay lower sens Confirm dx w/ antibodies to viral capsid antigen

(VCA), early antigens (EA) and EBNA

LFTs abnormal in 90%

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Infectious Mononucleosis

Diagnosis

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Infectious Mononucleosis

Treatment Rest Analgesics Avoid excessive physical activity (risk for

splenic rupture). Prednisone for severe airway obstruction,

hemolytic anemia, or thrombocytopenia. No role for acyclovir

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Infectious Mononucleosis

Prognosis Most cases are self limited Complications include

Meningitis/Encephalitis (

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References

Harrisons Principles of Internal Medicine16 th ed, Kasper et al, c 2005

Emedicine