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common in young adults (ages 17-25 years), where it is transmitted by passage of infectious salivary
secretions (kissing disease). In endemic regions, almost all children are infected by 3 years of age. EBV
infects 80-90% of all persons by adulthood, but only 50% will develop clinical disease. Time from infection
to appearance of symptoms is 4-6 weeks.
Risk Factors: Transmission is facilitated by crowded conditions allowing close contact, such as among
military recruits. Because of prolonged excretion of infectious virus, transmission may be maintained in
susceptible communities for months.
Subjective: Symptoms
Acute (2-7 days): Fever, chills, malaise, anorexia, severe sore throat Sub-acute (1-2 weeks): Fever,
fatigue, malaise, severe sore throat, rash, swollen lymph nodes in neck Chronic (2 Weeks to 3 months):
Fatigue, malaise
Focused History: Do you have a cough? (IM rarely has clinical pulmonary manifestations) How long have
you felt sick? What were your rst symptoms? (Usually, a patient presents with malaise lasting several days
to a week, followed by fever, sore throat, and enlarged lymph nodes in the neck.) Has anyone you live
with or been sick with a similar illness in the past few months? (indolent but contagious illness, requiring
exchange of saliva)
Objective: Signs
Using Basic Tools
Vitals: Fever to 100.4 – 104°F, typically peaks in afternoon
Inspection: Nontoxic appearance, swollen neck, faint measles-like rash, pharyngitis with edema or exudative
tonsillitis, palatal petechiae (red spots on back of throat)
Palpation: Splenic enlargement, +/- hepatomegaly; swollen cervical lymph nodes (discrete, firm to touch,
tender but without fluctuance).
Auscultation: Stridor from upper airway obstruction (rare)
Percussion: Mild tenderness over liver
Using Advanced Tools: Lab: Monospot Test positive; differential reveals lymphocytosis with >10% atypical
lymphocytes.
Assessment:
Differential Diagnosis
Pharyngitis
Other upper respiratory tract infections (see Respiratory: Common Cold and Flu). Mononucleosis persists
longer.
Hepatitis A, B - prolonged malaise and fatigue, but jaundice is typically observed later
Hepatomegaly - cytomegalovirus and HIV are less likely to be associated with severe pharyngitis.
Toxoplasma and rubella - rare causes of IM-like syndromes, but may be a significant risk to the fetus if
they occur during pregnancy.
Generalized lymphadenopathy - zoonoses such as brucellosis and leptospirosis are unlikely (see topics in
ID).
Plan:
Treatment
- Treatment is supportive, usually for relief of throat pain and fevers (see Procedure: Pain Assessment &
Control). - For impending airway obstruction give Prednisone 1 mg/kg po qd x 3 days, then taper over a week.
Alternatively, give Prednisone 50 mg po and taper off by 10 mg/d over 5 days.
Patient Education
General: No heavy lifting or contact sports or parachuting for 2 months after onset of illness to prevent
splenic rupture.
Activity: Rest during acute illness