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Background
- Caused by Epstein-Barr virus
- CMV and HHV-6 may cause mononucleosis-like illnesses
- Infects B lymphocytes which causes dissemination
- T lymphocytes fight infection
- In patients with decreased T cell function, can lead to continued proliferation and neoplastic transformation
Clinical Features
Neck lymphadenopathy associated with infectious mononucleosis.
Exudative pharyngitis in a person with infectious mononucleosis.
Rash from using penicillin while infected with mono.
- Triad of:
- Symptoms
- Abrupt or insidious
- Headache, fever, and malaise common, sore throat and lymphadenopathy follow
- Rash in 10-15% usually between 4th-6th day of illness
- Red macular or maculopapular morbilliform rash of trunk & upper arms
- Occasionally involves face, thigh and legs, periorbital & eyelid edema in 50% of cases
- Most often mono is diagnosed based on other signs [1]
- Previously treated as strep pharyngitis
- Illness typically 2-4 weeks, but malaise and fatigue may last for months
Differential Diagnosis
Bacterial infections
Viral infections
Noninfectious
Other
Evaluation
Splenomegaly due to mononucleosis resulting in a subcapsular hematoma
Work-up
- Heterophile antibody (monospot) test vs EBV IgM Assay
- CBC
- Lymphocytosis (≥50% lymphocytes)
- 10% or more atypical lymphocytes
- Hypersegmented neutrophils
- Thrombocytopenia
- LFTs
- Elevations in AST and ALT is expected up to 5x
- Suspected mononucleosis during pregnancy (also need to rule out other pathology):
Diagnosis
- Heterophile antibody (monospot) test
- Sensitivity of 87% and specificity of 91% [4]
- Up to 25% of patients in 1st week of symptoms may have false negative test[5]
- 10% of adult patients with EBV infection will be persistently negative
- Up to 50% of pediatric patients will be persistently negative[6]
- EBV IgM Assay
- Carries 97% sensitivity and 94% specificity at symptom onset[7]
Management
- Supportive
- Avoid contact sports for 1-2 months[8] (decrease risk of splenic rupture)
Disposition
References
- ↑ Sara Bode; Contagious Exanthematous Diseases. Quick References 2022; 10.1542/aap.ppcqr.396150
- ↑ Luzuriaga K and Sullivan JL. Infectious mononucleosis. N Engl J Med. 2010; 362:1993-2000.
- ↑ Melio, Frantz, and Laurel Berge. “Upper Respiratory Tract Infection.” In Rosen’s Emergency Medicine., 8th ed. Vol. 1, n.d.
- ↑ Sylvester JE, Buchanan BK, Silva TW. Infectious Mononucleosis: Rapid Evidence Review. Am Fam Physician. 2023 Jan;107(1):71-78. PMID: 36689975.
- ↑ Pitetti RD, Laus, S, and Wadowsky, RM. Clinical evaluation of a quantitative real time polymerase chain reaction assay for diagnosis of primary Epstein-Barr virus infection in children. Pediatr Infect Dis J. 2003; 22:736–739.
- ↑ Papesch M and Watkins R. Epstein-Barr virus infectious mononucleosis. Clin Otolaryngol Allied Sci. 2001; 26(1):3-8.
- ↑ Bruu, AL, et al. Evaluation of 12 commercial tests for detection of Epstein-Barr virus-specific and heterophile antibodies. Clin Diagn Lab Immunol. 2000; 7:451–456.
- ↑ O'Connor TE, Skinner LJ, Kiely P, Fenton JE. Return to contact sports following infectious mononucleosis: the role of serial ultrasonography. Ear Nose Throat J. 2011 Aug;90(8):E21-4.