Mononucleosis

Aka: Mononucleosis, Acute Mononucleosis Syndrome, Epstein-Barr Virus, Epstein Barr Virus, EBV-Induced Mononucleosis, EBV

1. Etiology
   1. Epstein-Barr Virus
      1. Human Herpes Virus (Herpesviridae)
      2. Infects B Cells (B-Cell Lymphotrophic)
   2. Adults who have been infected and are carriers: 90%
2. Transmission
   1. Transmission through infected Saliva (kissing)
   2. Oral secretions transmit for up to 6 months
3. Epidemiology
   1. Adolescents and young adults
      1. Incidence ages 10 to 19 years: 6-8 per 1,000/year
      2. Incidence ages <10 years: <1 case per 1,000/year
         1. Likely underestimates Incidence
         2. Often these children have subacute presentations
      3. Peak Incidence
         1. Girls: 14-16 years old
         2. Boys: 16-18 years old
   2. Commonly occurs in congested, confined spaces
      1. College Students
      2. Military recruits
4. Incubation
   1. Range: 4-8 weeks (may be as short as 2 weeks)
5. Symptoms
   1. Fever (in >97% of cases)
      1. Persists for 7-10 days
   2. Chills
   3. Malaise
   4. Fatigue (Test Sensitivity: 93%)
   5. Myalgia
   6. Severe Sore Throat
6. Signs
   1. Exudative Pharyngitis (>97%)
   2. Prominent cervical Lymphadenopathy (>97%)
      1. Posterior cervical Lymphadenopathy most common
      2. Axillary and Inguinal Lymphadenopathy also common
   3. Pharyngeal erythema and edema (85%)
   4. Splenomegaly (75%)
   5. Palatal Petechiae (50%)
   6. Periorbital edema (33%)
   7. Hepatomegaly (20%)
7. Labs
   1. Throat Culture
      1. Exclude coexisting Streptococcal Pharyngitis
      2. Concurrent Strep PharyngitisIncidence: 4-30%
      3. If positive, avoid Amoxicillin due to rash
   2. Lymphocyte predominance: >50%
   3. Lymphocyte atypia >10%
      1. Very specific to EBV
      2. No further tests needed if Lymphocyte atypia present
      3. 
   4. Heterophil Antibody Test (Monospot Test)
      1. Efficacy: 95% sensitive and Specific
   5. Antibodies to EBV antigens:
      1. Acute phase antibodies: xEA, xIgM VCA
      2. Convalescent Antibody: xIgG VCA
      3. Recovered State: xIgG VCA, xEBNA
8. Differential Diagnosis
   1. See Mononucleosis Differential Diagnosis
9. Diagnosis
   1. See Mononucleosis Diagnostic Approach
10. Management
    1. Symptomatic
       1. Rest
       2. Non-caffeinated fluids for adequate hydration
       3. Analgesics (NSAIDs or Acetaminophen)
       4. See Pharyngitis Symptomatic Treatment
    2. Avoid strenuous Exercise or contact sport
       1. Risk of splenic rupture
       2. Return to play
          1. Three weeks: Moderate training allowed
             1. No Splenomegaly
             2. No fever
             3. Liver Function Tests Normal
             4. Asymptomatic
          2. Four weeks: strenuous activity allowed
    3. Severe odynophagia or Airway compromise
       1. Oral Prednisone 30-50mg PO qd tapered 10-14 days or
       2. Oral Dexamethasone 0.3 mg/kg
          1. May require repeat doseing
    4. Antibiotics
       1. Only indicated for coexisting Strep Throat
       2. Rash develops in 90% of EBV patients on antibiotics
          1. Especially with Ampicillin
    5. Other ineffective agents
       1. No benefit with Acyclovir
       2. No benefit with Ranitidine
11. Complications
    1. Meningoencephalitis
    2. Guillain-Barre Syndrome
    3. Bell's Palsy
    4. Pneumonitis
    5. Pericarditis
    6. Myocarditis
    7. Peritonsillar Abscess: 0.2%
    8. Rheumatic Fever: 0.2%
    9. Syndrome of inappropriate Antidiuretic Hormone (SIADH)
    10. Splenic rupture (days 4-21): 0.1-0.2% Incidence
    11. Airway Obstruction
    12. Hemolytic Anemia
    13. Thrombocytopenia
    14. Acute Interstitial Nephritis
    15. Retrobulbar neuritis
12. Associated Conditions
    1. Chronic Fatigue Syndrome (possibly same viral agent)
13. Course
    1. Athletes require 3-6 months to return to prior fitness
    2. Fatigue or Hypersomnia persists 6 months in 9-22%
    3. Fatigue present
       1. Initial: 77%
       2. Month 1: 28%
       3. Month 2: 21%
       4. Month 6: 13%
    4. Hypersomnia present
       1. Initial: 45%
       2. Month 1: 18%
       3. Month 2: 14%
       4. Month 6: 9%
    5. Arthralgias present
       1. Initial: 23%
       2. Month 1: 15%
       3. Month 2: 6%
       4. Month 6: 9%
    6. References
       1. Rea (2001) J Am Board Fam Pract 14:234-42
14. Resources: Patient Education
    1. AAFP Family Doctor Patient Education Handout
       1. http://www.familydoctor.org/handouts/077.html
15. References
    1. Katz in Gershon (2004) Krugman's ID, p. 143-55
    2. Gantz in Noble (2001) Primary Care, p. 267-71
    3. Ebell (2004) Am Fam Physician 70(7):1279-87