What is the treatment for infectious mononucleosis?

Infectious Mononucleosis: Symptoms, Laboratory Findings, and Treatment

Clinical Presentation

Infectious mononucleosis typically presents with a classic triad of fever, tonsillar pharyngitis, and lymphadenopathy, most commonly affecting adolescents and young adults aged 15-24 years. 1

Key Symptoms

• Fever and profound fatigue that typically resolves within three months 1
• Sore throat with tonsillar pharyngitis and palatal petechiae 2
• Lymphadenopathy, particularly posterior cervical or auricular nodes 2
• Periorbital and/or palpebral edema (bilateral) occurs in one-third of patients 1
• Splenomegaly in approximately 50% of cases 1
• Hepatomegaly in approximately 10% of cases 1
• Maculopapular rash (erythematous, widely scattered) in 10-45% of cases 1

Causative Pathogens

• Epstein-Barr virus (EBV) is the primary cause 3
• Alternative causes include cytomegalovirus (CMV), Toxoplasma gondii, and acute HIV infection 3

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Laboratory Findings

Complete Blood Count

• Peripheral blood leukocytosis with lymphocytes comprising at least 50% of the white blood cell differential 1
• Atypical lymphocytes constituting more than 10% of the total lymphocyte count 1
• Lymphocytosis ≥50% and atypical lymphocytosis ≥10% strongly support the diagnosis 4

Serologic Testing

The heterophile antibody test (Monospot) is the most widely used initial diagnostic test, with 87% sensitivity and 91% specificity. 4

Heterophile Antibody Testing

• Becomes positive between the sixth and tenth day after symptom onset 4
• False-negative results are common in children younger than 10 years (approximately 10% false-negative rate overall) 4
• False-positive results may occur in leukemia, pancreatic carcinoma, viral hepatitis, and CMV infection 4

EBV-Specific Serology (when heterophile test is negative)

When clinical suspicion remains high despite a negative heterophile test, EBV serologic testing should include: 4

• IgM antibodies to viral capsid antigen (VCA)
• IgG antibodies to VCA
• Antibodies to Epstein-Barr nuclear antigen (EBNA)

Interpretation: 4

• VCA IgM present (with or without VCA IgG) + EBNA absent = recent primary EBV infection
• EBNA antibodies present = infection occurred more than 6 weeks prior
• Over 90% of normal adults have IgG antibodies to VCA and EBNA, reflecting past infection

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Treatment Approach

Supportive Care (Mainstay of Treatment)

Treatment is primarily supportive, as infectious mononucleosis is generally a benign and self-limited disease. 1

Activity Modification

• Reduction of activity and bed rest as tolerated (bed rest should not be enforced; patient's energy level should guide activity) 2
• Avoid contact sports or strenuous exercise for 8 weeks or while splenomegaly is still present 1
• Critical caveat: Spontaneous splenic rupture occurs in 0.1-0.5% of patients and is potentially life-threatening 1

Symptomatic Management

• Adequate hydration 2
• Analgesics and antipyretics for pain and fever 2
• Adequate rest 2

Medications NOT Routinely Recommended

Aciclovir therapy does not ameliorate the course of infectious mononucleosis in otherwise healthy individuals. 4

• Antihistamines are not recommended for routine treatment 2
• Antiviral agents (aciclovir, ganciclovir, foscarnet) have no proven role in established disease in immunocompetent patients 5

Corticosteroids (Limited Indications Only)

Corticosteroids should be reserved for specific complications only: 4

• Respiratory compromise 2
• Severe pharyngeal edema 2
• Not recommended for routine treatment 2

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Special Populations and Severe Disease

Immunocompromised Patients

In immunocompromised patients with suspected primary EBV infection, immunomodulator therapy should be reduced or discontinued if possible. 5

• Increased risk of lymphoproliferative disorders and hemophagocytic syndrome 4
• In severe primary EBV infection, antiviral therapy with ganciclovir or foscarnet may be considered despite lack of supporting evidence 5
• Specialist consultation should be sought for suspected lymphoproliferative disease 5

Patients on Thiopurine Therapy

• Primary EBV infection poses particular threat in patients on thiopurines, with reports of fatal infectious mononucleosis-associated lymphoproliferative disorders 5
• EBV screening should be considered before initiating thiopurine therapy 4

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Differential Diagnosis When Tests Are Negative

When heterophile and EBV testing are negative, consider: 4

• Cytomegalovirus (CMV) infection
• HIV infection
• Toxoplasma gondii infection
• Adenovirus infection
• Streptococcal pharyngitis

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Common Pitfalls to Avoid

• Do not rely solely on heterophile testing early in illness (false-negatives common in first week) 4
• Do not use heterophile testing in children under 10 years (high false-negative rate) 4
• Do not prescribe routine antiviral therapy in immunocompetent patients (no proven benefit) 4
• Do not allow return to contact sports before 8 weeks or while splenomegaly persists (risk of splenic rupture) 1
• Do not prescribe routine corticosteroids (reserve for airway compromise only) 2