Infectious mononucleosis
Infectious mononucleosis
Updated: 09/10/2020
© Jun Wang,
MD, PhD
General features
- Febrile illness
- EB virus associated
- Spread by intimate contact, including breast feeding, saliva exchange and other sexual contacts
- Human likely major reservoir
- More common in young adults
- Higher risk for EBV associated malignancies, such as Hodgkin lymphoma, Burkitt lymphoma
Clinical presentations
- Most asymptomatic
- Incubation 1-2 months
- Triad of fever, tonsillar pharyngitis, and lymphadenopathy
- Other nonspecific presentations: fatigue,
- Hepatomegaly, jaundice, splenomegaly, etc
- Risk of fatal spontaneous spleen rupture
Key pathogenesis
- EB virus infection of B cells
- Infects reticular endothelial system (liver, spleen, lymph nodes, etc) through circulation
- B cells produce antibodies against EBV protein components
- T cells eliminate infected B cells
- Inflammatory reactions associated with clinical presentations
- B cell malignancy may develop due to uncontrolled proliferation if T cell function impaired
Key Laboratory findings
- Lymphocytosis
- Atypical lymphocytes
- Hemolytic anemia associated with anti-i cold agglutinin
- Abnormal liver function tests, usually self-limited
- Heterophile antibodies (monospot test, ELISA)
- EBV specific antibodies
- PCR for EBV DNA quantification
Key morphological features
- Large atypical lymphocytes with abundant basophilic cytoplasm and peripheral darkening, usually CD8+ T cells
Differential diagnosis
- Pharyngitis caused by other microorganisms, including bacteria, CMV, HIV, toxoplasma, etc: microbiology studies, molecular studies
- Drug reactions, including anticonvulsants (phenytoin, carbamazepine, isoniazid, etc): History, lab tests for EBV
- Lymphomas: Tests to rule out monoclonal proliferation
Management
- Supportive care
- Corticosteroid/otolaryngologist consultation for airway obstruction
- Antiviral treatment: acyclovir, etc
- Avoiding splenic rupture, refrain from sports for at least 3 to 4 weeks
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