Mumps Virus

Snapshot

• A 4-year-old boy presents to the emergency room for fevers and swollen jaw. He had recently gone to Disneyland with classmates. His family had been among several who were against vaccinations, and so he had not received regular vaccines since birth. He only received the first dose of the measles, mumps, and rubella vaccine. On physical exam, he has a low-grade fever and bilateral swollen parotid glands that are tender to palpation.

Introduction

• Classification
  • mumps virus 
    • a paramyxovirus
    • a linear single-stranded, negative sense RNA virus
    • helical capsid
    • transmission via respiratory secretions
    • most commonly causes parotitis and orchitis
    • can also rarely cause aseptic meningitis and pancreatitis
• Epidemiology
  • incidence
    • decreased worldwide due to effective vaccination
    • highest in winter and spring
  • demographics
    • higher in children
  • risk factors
    • exposure to others with mumps or unvaccinated people
    • crowded living environment
      • college dorm
    • lack of vaccination
• Pathogenesis
  • all paramyxoviruses contain the F (fusion) protein
    • can induce cell-to-cell fusion, creating multi-nucleated giant cells
    • helps mediate virus and cell membrane fusion, ultimately resulting in infection of the host cell
  • the virus replicates in the nasopharynx and regional lymph nodes in the glandular epithelium  
• Prevention
  • measles, mumps, and rubella (MMR) vaccine
    • given over 2 doses in childhood
• Prognosis
• patients infected with mumps virus are often asymptomatic

Presentation

• Symptoms
  • parotitis
    • earache
    • pain in the jaw
  • prodrome
    • low-grade fever
    • malaise
    • headache
  • orchitis 
    • pain in testes
• Physical exam
  • parotitis 
    • bilateral or unilateral parotid gland swelling
    • tenderness to palpation
    • earlobe lifted up and outward
  • orchitis
• bilateral or unilateral testes swelling

Studies

• Labs
  • detection of antibodies immunoglobulin M or G
  • buccal or oral swab with viral isolation or detection on reverse transcriptase-polymerase chain reaction
• Making the diagnosis
• based on clinical presentation and confirmed with laboratory studies

Differential

• Epstein-Barr virus
  • distinguishing factor
• may also cause parotitis, but also often causes mononucleosis

Treatment

• Management approach
  • mainstay of treatment is supportive care and prevention with vaccines
• Conservative
  • supportive care
    • indication
      • all patients
    • modalities
      • anti-pyretics
      • analgesics
• hydration

Complications

• Sterility in males who have orchitis after puberty
• Sensorineural deafness