Mumps

Mumps is a highly contagious viral infection that is transmitted via infectious respiratory particles and primarily affects children. Since the introduction of the measles, mumps, and rubella (MMR) vaccine, the incidence has declined in the US. Mumps characteristically manifests with viral sialadenitis, particularly parotitis, which typically progresses from unilateral to bilateral. Prodromal symptoms may include low-grade fever, malaise, and headache. RT-PCR confirms active infection. Mumps is usually a self-limited disease with a good prognosis. Management includes isolation, supportive therapy, and, for patients with parotitis, symptomatic management for sialadenitis. Complications include mumps orchitis, aseptic meningitis, hearing loss, and pancreatitis. Immunization with the MMR vaccine or MMRV vaccine is recommended for all children and for adults without evidence of immunity.

• 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]
• Risk factors: See “Risk factors for measles, mumps, and/or rubella.”

Epidemiological data refers to the US, unless otherwise specified.

• 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 ^[4][5]
  • Highly infectious
  • Affected individuals are contagious ∼ 3 days before and up to 9 days after disease onset (when the parotid gland becomes swollen).
• Incubation period: 16–18 days ^[6]

Asymptomatic cases are also contagious.

• Nasopharyngeal entry → replication of the virus in the mucous membranes and lymph nodes → viremia and secondary infection of the salivary glands (particularly the parotid gland) → further dissemination possible (lacrimal, thyroid, and mammary glands, pancreas, testes, ovaries, CNS)

• Prodrome
  • Duration: 3–4 days
  • Symptoms: low-grade fever , malaise, headache
• Classic course: inflammation of the salivary glands, particularly parotitis ; ^[5][8]
  • 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
    • A flat, red rash that begins on the face and disseminates to the rest of the body can occur.
  • Chronic courses are rare.
• Subclinical presentation ^[6]
  • Nonspecific or predominantly respiratory symptoms
  • Asymptomatic (in 15–20% of cases) ^[4]

Infection control ^[9][10][11]

• Isolate patient and institute standard precautions and droplet precautions.
• Ensure that only health care professionals with evidence of mumps immunity provide direct care to the patient.
• Notify the local health department promptly of suspected mumps.

Mumps is a nationally notifiable disease; promptly report all suspected and confirmed cases to the local health department.

Diagnostics ^[9][10][11]

Obtain and interpret diagnostic studies in all individuals with clinical features of mumps or complications of mumps, in coordination with the health department.

Studies

• RT-PCR of buccal swab: Obtain in the following patients. ^[11]
  • Parotitis only and ≤ 10 days since symptom onset ^[11]
  • Complications of mumps, regardless of symptom duration ^[12]
• RT-PCR of urine sample: Obtain in addition to buccal swab in patients who meet both the following criteria. ^[11]
  • Mumps orchitis but no parotitis
  • ≤ 10 days since symptom onset
• Serology of mumps-specific IgM antibodies: Obtain in addition to RT-PCR in patients with the following features.
  • Parotitis only and > 3 days since symptom onset ^[11]
  • Complications of mumps, regardless of symptom duration ^[12]

RT-PCR is preferred to confirm acute mumps. Sample should be collected as soon as possible and within 10 days of rash onset. ^[11]

Interpretation of results

• Only a positive RT-PCR; or viral culture result is confirmatory of acute infection. ^[11]
• Positive mumps-specific IgM antibodies support the diagnosis but cannot confirm it.
• Negative test results cannot rule out acute mumps infection in patients with clinical features of mumps.

A negative test result in a patient with typical clinical features of mumps should be presumed to be a false negative. ^[9]

Further management ^[7]

• Mumps is usually self-limited with a good prognosis.
• Provide supportive care, e.g.:
  • Supportive care for pediatric fever
  • Symptomatic management of salivary gland disorders for patients with parotitis (e.g., NSAIDs for pain relief, oral hydration) ^[13][14]
• Instruct patients and exposed contacts on isolation precautions; see “Exposure control for mumps.”

• Differential diagnosis of salivary gland swelling
• Differential diagnosis of orchitis: epididymitis, testicular torsion
• Differential diagnosis of aseptic meningitis (See “Meningitis.”)

The differential diagnoses listed here are not exhaustive.

Mumps 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 men and boys) ^[6][15]
• Clinical features
  • Sudden onset of fever, nausea, vomiting
  • Swollen and tender affected testicle(s); primarily unilateral, although bilateral in ∼ 15% of cases
• Diagnostics: clinical diagnosis; manifests ≤ 7 days after parotitis develops ^[16]
• Treatment ^[16]
  • Typically self-limited, resolving in ≤ 10 days
  • Supportive therapy (e.g., bed rest, warm or cold compresses)
• Complications: : may lead to atrophy and, rarely, hypofertility

Other complications ^[4]

• Aseptic meningitis: (1–10% of cases): predominantly mild course and usually no permanent sequelae
• Encephalitis (< 1% of cases)
  • Reduced consciousness, seizures
  • Neurological deficits: cranial nerve palsy, hemiplegia, sensorineural hearing loss (rare)
• Acute pancreatitis (< 1% of cases)
  • Vomiting, nausea, upper abdominal pain
  • ↑ Lipase in addition to ↑ amylase
  • Diabetes mellitus type I (delayed complication) ^[6]
• Hearing loss (extremely rare)

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

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

Vaccination ^[17][18][19]

Administer a live attenuated mumps vaccine; (i.e., MMR vaccine, MMRV vaccine) according to the ACIP immunization schedule. See the following:

• Immunizations for measles, mumps, and rubella
• ACIP immunization schedule
• Contraindications to live vaccines (e.g., pregnancy, immunocompromise)

Exposure control for mumps ^[10][20]

Suspected and confirmed cases

• Hospitalized patients: Initiate standard precautions and droplet precautions.
• Isolate for 5 days from the development of parotitis.

Close contacts

• All contacts without evidence of immunity to mumps
  • Individuals without contraindications to live vaccines: Administer the MMR vaccine to protect against future exposures. ^[21]
  • Recommend the following:
    • Avoid large gatherings.
    • Monitor for symptoms through day 25 after last exposure; if symptoms develop, isolate for 5 days. ^[20]
  • Refer to the health department for additional guidance regarding isolation.
• Health care workers ^[22]
  • With evidence of immunity to mumps or with documented 1 dose of MMR before exposure:
    • May continue to work, but monitor for symptoms from day 10 after first exposure until day 25 after last exposure
    • If only 1 dose previously, give second dose of MMR vaccine as soon as possible.
  • No prior MMR vaccine doses: Exclude from work from day 10 after first exposure until day 25 after last exposure.