Mumps

Aka: Mumps, Epidemic Parotiditis, Epidemic Parotitis

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II. Epidemiology

  1. Peak Age 10-19 years
  2. Incidence
    1. U.S. Cases in 1968: 152,000 cases
    2. U.S. Cases in 2000: 338 cases
    3. U.S. Cases in 2015: 1057 cases

III. Pathophysiology

  1. Caused by a paramyxovirus
  2. Transmission: 2 days before parotid swelling, to 5 days after
    1. Transmitted easily by airborne droplet spread (Saliva or nasal secretions)
    2. Also transmitted in urine
  3. Incubation: 12-25 days (typically 16-18 days)
  4. Infectious:
    1. Start: 6 days before Parotitis
    2. Ends: 2 weeks after symptom onset

IV. Symptoms

  1. Subclinical presentation in 20-40% of cases
  2. Prodrome (onset after 12-25 day Incubation Period)
    1. Fever (moderate, lasts 7 days)
    2. Malaise
    3. Headache
    4. Anorexia
    5. Myalgias
  3. Sudden onset pain, swelling, tenderness in cheeks at Parotid Gland lasting >2 days
    1. Starts as unilateral and becomes bilateral in 90% of cases
    2. Provoked by chewing or Swallowing
    3. Worse with sour foods or acidic foods
  4. Associated Symptoms
    1. Otalgia
    2. Trismus

V. Signs

  1. Sialadenitis
    1. Parotitis occurs in 30-40% of patients
      1. Submandibular and Sublingual Glands may also become inflamed and tender in 10% of cases
    2. Typically bilateral involvement (but may start unilaterally)
    3. Skin over Parotid Gland not warm or red
      1. Contrast with Bacterial Sialadenitis
    4. Tenderness and swelling at mandibular angle (may obscure angle of jaw)
    5. Parotid duct (Stensen duct) opening appears red and edematous in Buccal mucosa
  2. Orchitis (3-10% of postpubertal males, up to 40% of males overall)
    1. Occurs 7-10 days after Parotitis
  3. Maculopapular rash
    1. Variably present
    2. May develop over the trunk

VI. Complications

  1. Orchitis (40% of cases)
    1. See signs (as above)
    2. Testicular Atrophy (50%)
    3. Bilateral Orchitis in 30% of cases
    4. Infertility (13% of cases)
      1. Highest risk if bilateral involvement
  2. Central Nervous System Involvement
    1. Asymptomatic Cerebrospinal Fluid Leukocytosis (50%)
    2. Less common causes
      1. Encephalitis (1 case per 400 to 6000 Mumps cases)
        1. Mortality: 1-2% death rate from Encephalitis
        2. Consider for high fever, Headache, neck stiffness or Seizures
      2. Aseptic Meningitis (10% of cases)
        1. Typically benign, but some will develop severe neurologic complications
      3. Paralytic Polio-like syndrome
      4. Transverse Myelitis
      5. Cerebellar Ataxia
  3. Miscellaneous
    1. Deafness (<1% in the post-Vaccine era)
    2. Oophoritis (ovarian inflammation)
      1. May present similarly to Appendicitis
    3. Subacute Thyroiditis
    4. Dacryoadenitis
    5. Optic Neuritis
    6. Iritis
    7. Conjunctivitis
    8. Myocarditis
    9. Pancreatitis (usually uncomplicated)
    10. Hepatitis
    11. Nephritis
    12. Mastitis
    13. ThrombocytopeniaPurpura
    14. Interstitial Pneumonia
    15. Migratory polyarthritis

VII. Labs: General

  1. Complete Blood Count
    1. Parotitis: Relative Lymphocytosis
    2. Orchitis: Marked Leukocytosis
  2. Serum Amylase increased (in Parotitis)
  3. Cerebrospinal Fluid
    1. White Blood Cells: 1000-2000 with Neutrophils

VIII. Diagnosis: Culture, IgG, and IgM should all be done

  1. Mumps PCR buccal swab
    1. Sample from respiratory secretions, urine or CSF
  2. Culture
    1. Obtain sample within first 5 days of Parotitis
    2. Blood, Throat, CSF, Urine
    3. Immunofluorescence positive in 2-3 days
  3. Serology
    1. Mumps IgM
      1. Positive after day 3 of swelling
      2. Titers peak by one week
    2. Mumps IgG
      1. Obtain acute baseline Mumps IgG as soon as possible
      2. Check Mumps IgG again 3-5 weeks after onset
      3. Titer increases 4 fold

IX. Management

  1. Parotitis
    1. Avoid sour or acidic foods
  2. Orchitis
    1. Scrotal support
    2. NSAIDs
    3. Consider Interferon alpha 2b
      1. Reduces testicular atrophy and Infertility risk
  3. Intravenous Immunoglobulin (IVIG) Indicated for specific autoimmune complications
    1. Guillain-Barre Syndrome
    2. Idiopathic Thrombocytopenia
    3. Post-Infectous Encephalitis
    4. NOT indicated in Postexposure Prophylaxis (not effective)
  4. Consider MMR Vaccine dose for contagious contacts who have been previously vaccinated (2 prior MMR doses)
    1. Consider third dose MMR Vaccine which may help prevent mumps infection during an outbreak
    2. Immunoglobulin is not effective for Post-exposure Prophylaxis
  5. Suspected cases
    1. Report to local public health department
    2. Follow standard isolation with droplet precautions (respiratory and Saliva sources) while in hospital
    3. Quarantine patient for 2 days before until 5 days after parotid swelling onset

X. Prevention

  1. MMR Vaccine
    1. MMR Vaccine is contraindicated in pregnancy and Immunocompromised patients (Live Vaccine)
    2. MMR Vaccine is indicated for all children in U.S. at 12-15 months and 4-6 years (Primary Series)
    3. Effective at preventing mumps in 88% of immunized patients (78% after the first dose)
    4. Antibody levels wane over time (esp. elderly), and may present atypically with mumps
    5. Immunize unvaccinated contacts (if not contraindicated) to prevent future cases
      1. However not effective for the index case Postexposure Prophylaxis
      2. Immune globulin is also NOT effective for Postexposure Prophylaxis

XI. Prognosis

  1. Mortality: Up to 50 deaths per 1 million Mumps cases

XII. Resources

  1. CDC Mumps
    1. http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/mumps.pdf
  2. Medscape EMedicine
    1. http://reference.medscape.com/article/966678-overview

XIII. References

  1. Harrison and Ruttan (2019) Crit Dec Emerg Med 33(7): 3-12
  2. Harrison and Ruttan (2023) Crit Dec Emerg Med 38(2): 23-31
  3. Spencer (2017) Am Fam Physician 95(12): 786-94 [PubMed]

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