Infectious Mononucleosis
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Contents |
Etiology
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- generally occurs through infected saliva, probably requiring repeated & prolonged contact with infected oral secretions, yet few patients can identify a known contact
- rarely blood transfusions or bone-marrow transplant
- viral excretion occurs for months
- asymptomatic carrier state is common
- infrequent causes < 10%
- cytomegalovirus ( CMV)
- human immunodeficiency virus ( HIV)
- Toxoplasma gondii
- human Herpes virus type 6
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Epidemiology
- endemic in children in developing countries
- most common in adolescence & young adulthood in developed nation with adequate sanitation
Clinical-manifestations
- incubation period is 3-7 weeks
- acute phase lasts 1-2 weeks with recovery in 6-8 weeks
- wide spectrum of disease from asymptomatic to fulminant infection leading to death in immunocompromised individuals
- overt illness most common in adolescents & young adults
- prodrome of malaise, fatigue & persistent low-grade headache
- severe exudative pharyngitis is the most prominent feature
- flu-like symptoms of fever/ chills, myalgias, arthralgias, nausea, abdominal discomfort, cough
- petechiae on the palate
- stiff neck
- lymphadenopathy
- splenomegaly
- hepatomegaly
Laboratory
- complete blood count ( CBC) with differential
- absolute lymphocytosis (> 50%)
- atypical lymphocytes (> 10%)
- liver function tests ( LFTs) may be elevated 2-3 fold
- direct antiglobulin test ( DAT, Coombs' test)
- heterophile antibody test ( Monospot test)
- serology, if heterophile antibody negative
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- useful for evaluation of nasopharyngeal carcinoma
- antibodies to EBV early antigens (anti-EA)
- antibodies to EBV nuclear antigen (anti-EBNA)
Radiology
Complications
Differential-diagnosis
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- exudative pharyngitis with group A beta hemolytic streptococci
- Mycoplasma
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- viral hepatitis
- rubella
- mumps
- human immunodeficiency virus ( HIV)
- herpesvirus type 6
Management
- uncomplicated acute infectious mononucleosis generally requires only supportive therapy
- warm salt water or anesthetic gargle for pharyngitis
- acetaminophen for fever or malaise
- antibiotic treatment of concomitant group A beta hemolytic streptococcus
- penicillin or erythromycin for 10 days
- avoid ampicillin or amoxicillin because they frequently produce a morbilliform rash in patients with infectious mononucleosis
- prednisone 40-80 mg QD with 5-14 day taper
- may shorten duration of fever
- can reduce obstructive tonsillar enlargement
- may improve cardiac, neurologic & hematologic complications
- rest with limited activity to prevent splenic rupture
- gradual return to activity with degree of splenomegaly as a monitor (see radiology)
- isolation unnecessary: EBV shedding continues after acute illness
More General Terms
Additional Terms
References
Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 872-73
