• Clinical science

Mumps

Summary

Mumps is a highly contagious viral infection that is transmitted via airborne droplets. The incidence is now very low in the US because of the combined measles, mumps, and rubella (MMR) vaccine. The condition primarily affects children between the ages of five and fourteen. Classically, it manifests with parotitis, which initially occurs unilaterally, but typically progresses to involve both sides. The lateral cheek and jaw area usually show marked swelling and the ears may protrude. Other symptoms include low-grade fever, malaise, headache, and possible swelling of other salivary glands. The diagnosis of mumps is largely based on clinical findings. Many cases, however, present with nonspecific features and are not easily recognizable as mumps. If possible, diagnosis should be confirmed with laboratory tests. Treatment is symptomatic. Rare complications include orchitis, aseptic meningitis, hearing loss, and pancreatitis. Immunization offers the best protection against future exposure. Mumps is a self-limiting disease, followed by lifelong immunity. The prognosis in uncomplicated cases is very good.

Epidemiology

  • Incidence: drastically declined in the US since the introduction of the MMR vaccine [1][2]
  • Peak age: 5–14 years of age
  • Sex: = for parotitis; (however, males are three times more likely to have CNS complications) [3]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

  • Pathogen: Mumps virus from the Paramyxoviridae family
  • Transmission [4]
    • Humans are the sole host and the virus is transmitted via airborne droplets.
    • Direct contact with contaminated saliva or respiratory secretions
    • Contaminated fomites
  • Infectivity [5][4]
    • Highly infectious
    • Affected individuals are contagious ∼ 3 days before and up to 9 days after disease onset (when the parotid gland becomes swollen).

Asymptomatic cases are also contagious.

Pathophysiology

Clinical features

  • Incubation period: 16–18 days [6]
  • Prodrome
    • Duration: 3–4 days
    • Symptoms: low-grade fever , malaise, headache
  • Classic course: inflammation of the salivary glands, particularly parotitis [5][7]
    • Duration of parotitis: at least 2 days (may persist > 10 days)
    • Symptoms
      • May initially present with local tenderness, pain, and earache
      • Unilateral swelling of the salivary gland (lateral cheek and jaw area); During the course of disease, both salivary glands are usually swollen.
      • Redness in the area of the parotid duct
      • Possible protruding ears
    • Chronic courses are rare.
  • Subclinical presentation [6]
    • Nonspecific or predominantly respiratory symptoms
    • Asymptomatic (in 15–20% of cases) [4]

Diagnostics

Laboratory tests, if available, should be conducted to confirm the suspected cases (especially if presentation is atypical or there is a mumps outbreak). [7][6][4]

Differential diagnoses

Differential diagnosis of parotid swelling [7]

Features Mumps Acute purulent sialadenitis Sialadenosis (sialosis) Sialolithiasis (salivary stones) Tumors of the salivary glands
Parotid swelling
  • Usually bilateral
  • Usually unilateral
  • Usually unilateral
  • Partial swelling of the gland
  • Usually unilateral
Pain
  • Painful
  • Painful
  • Usually painless
  • Painful while eating
  • Usually painless
Fever
  • Present
  • Present
  • Absent
  • Usually absent
  • May present
Other findings
  • Possible redness of the gland
  • Protruding ears
  • Possible pus discharge
  • Sudden pain while eating
  • Possible malignant symptoms of infiltrated structures (e.g., facial palsy)

The differential diagnoses listed here are not exhaustive.

Treatment

Mumps is usually self-limited with a good prognosis (unless complications arise). Treatment is mainly supportive care.

Complications

Orchitis

  • Definition: inflammation of the testis
  • Epidemiology: most common complication of mumps in postpubertal male individuals (20–30% in unvaccinated postpubertal and 6–7% in vaccinated males) [8][6]
  • Clinical features
    • Sudden onset of fever, nausea, vomiting
    • Swollen and tender affected testicle(s); primarily unilateral, although bilateral in ∼ 15% of cases
  • Complications: : may lead to atrophy and, in rare cases, hypofertility

Other complications [4]

The MEN of the PANamanian ORCHestra know how to throw a good PARty: MENingitis, PANncreatitis, ORCHhitis, and PARotitis are the most important complications of mumps.

We list the most important complications. The selection is not exhaustive.

Prevention

Mumps vaccination during the first trimester in pregnancy may lead to embryonal death.