Infectious Mononucleosis

Other Names

• Mono
• Kissing virus
• Kissing disease

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Background

• This page covers Infectious mononucleosis (IM), often referred to as 'mono'

Epidemiology

• It is estimated that 30-50% of college freshman are susceptible to infection
  • Annual incidence is 1-3%
• Although most commonly seen in teenagers, eventually infects up to 90% of all adults

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Pathophysiology

• Viral syndrome characterized by pharyngitis, posterior cervical lymphadenopathy, fatigue, fever, abdominal pain and sometimes rash
• Most commonly caused by primary Epstein-Barr virus (EBV) infection in teenagers
  • Transmission occurs primarily through oral secretions, hence the popular description "kissing disease"
  • Also shared through coughing, sneezing, close contact
  • Less commonly through blood, solid organ transplantation, hematopoeitic cell transplant
  • EBV is a member of the herpes virus family
  • Less commonly caused by cytomegalovirus (CMV)
• General
  • Illness is generally self limited
  • Classic triad of fever, pharyngitis and lymphadenopathy
  • Incubation period is between 30-50 days, which makes identifying initial exposure challenging
  • Patients who are immunocompromised can develop severe symptoms
• No season variation
• Acutely, increases risk of splenomegaly and rupture
• Chronically, EBV is associated with certain cancers and autoimmune disease

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Risk Factors

• Needs to be updated

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Differential Diagnosis

• Non-EBV Viral Pharyngitis
• Strep Pharyngitis
• Post Nasal Drip
• Allergic Reaction

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Clinical Features

• General
• History
  • Incubation period is approximately 6 weeks
  • May have a viral prodrome of fever, headache, malaise for up to 3 weeks
  • Patients endorse sore throat, cervical lymphadenopathy, fever, tonsillar enlargement
• Physical Exam
  • Pharygeal inflammation (80%)
  • Palatal petechiae (25%)
  • Rash on trunk and upper extremity (10-40%), more common if treated with antibiotics
  • Splenomegaly (up to 50%, need citation)
    • Ability to detect splenomegaly on exam is limited
    • Poor sensitivity, specificity and inter-rate reliability (need citation)
  • Older adults may develop jaundice
  • Less common: periorbital edema, CNS complications, myocarditis
• Special Tests

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Evaluation

Laboratory

• CBC shows nonspecific leukocytosis, lymphocytosis
• Heterophile antibody test positive
• LFTs may or may not bee elevated

Imaging Spleen

• CT, MRI and US have been used
• CT
  • Benefits: Greater detail, better quantifcation of splenic size
  • Limitations: cost, radiation exposure, time
  • Indicated if splenic rupture is suspected
• US
  • Readily available, inexpensive, no radiation
  • Technique
  • Measure length, breadth, thickness
  • Multiply all 3 dimensions, divide by 27
  • Interpret an individual measurement with caution. Likely need serial measurements
  • Clear guidance on normative data not well established

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Classification

• N/A

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Management

Hoagland's Criteria

• WBC: at least 50% lymphocytes and at least 10% atypical lymphocytes
• Presence of fever, pharyngitis, and adenopathy
• Confirmatory serologic testing
• Approximately 50% of patients meet

Nonoperative

• No specific treatment, self limited illness
• Supportive treatment
• Sore throat
  • Salt water gargles, anesthetic throat lozenges or sprays, or gargling with 2% lidocaine solution
• Acyclovir
  • Short term supression of viral shedding, no significant clinical benefit
• Oral Corticosteroids
  • Some benefit for severe pharyngeal edema
  • Consider in athletes with: impending airway obstruction, hemolytic anemia, severe thrombocytopenia, or myocarditis
  • Chochrane review: decreased symptoms for 12 hours, benefits subsided at 2-4 days
• Avoid
  • Activity/ sports until cleared by physician
  • If given penicillin, up to 90% of patients will develop a maculopapular rash (need citation)
  • Aspirin due to risk of bleeding, thrombocytopenia
  • Acetaminophen, alcohol due to hepatotoxicity
• Isolate from others if possible to minimize exposure and risk

Operative

• If splenic rupture, splenectomy
• Some case reports of nonoperative management of stable splenic injury
  • Discuss with surgical staff if patient is stable

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Rehab and Return to Play

Rehabilitation

• No specific rehabilitation
• Athlete may require conditioning before return to sport

Return to Play

• Return too quickly increases risk of splenic injury
  • Complicated by lack of clear correlation between splenomegaly and risk of rupture
  • Unreliability of physical exam also a challenge
  • Risk not well understood in athletes, estimated to be 0.1-0.5% extrapolating from general population (need citation)
  • Up to 86% of ruptures are atraumatic
• Sylvester et al: Less than 75% of ruptures occur before 21 days, most occur by 31 days
  • Case reports of splenic rupture up to 7 weeks (need citation)
• Most physicians hold athletes for 4-6 weeks
  • Consider light, noncontact activities 3 weeks from symptom onset
• Return to contact activities is controversial
  • RTP must be individualized
  • Important to discuss risk/benefit with athlete

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Complications

• Splenic Rupture
• Myocarditis
• CNS

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See Also

• Infectious Disease (Main)

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