Mumps

Essentials of Diagnosis

• Exposure 12–25 days before onset

• Painful, swollen salivary glands, usually parotid

• Frequent involvement of testes, pancreas, and meninges in unvaccinated individuals

• Mumps can occur in appropriately vaccinated persons in highly vaccinated communities

General Considerations

• Children are most commonly affected; however, in outbreaks, infection can affect patients in their second or third decades of life

• Mumps is more serious in adults than in children and appears to occur more commonly in males

• Incubation period is 12–25 days (average, 16–18 days)

• Transmission

  • Direct contact with respiratory secretions or saliva or infected surfaces

  • Can also be airborne or via droplets

  • Can spread rapidly in congregate settings, such as colleges and schools

  • Up to one-third of affected individuals have subclinical infection, which is still transmissible

Demographics

• From January 2016 to June 2017, 9200 cases were reported, including a large outbreak of close to 3000 cases in one Arkansas community

• Between January 1 and September 13, 2019, 47 states and the District of Columbia in the United States reported 2363 mumps cases

Symptoms and Signs

• Fever and malaise are variable but often minimal in young children

• Parotid tenderness and overlying facial edema

  • Most common physical findings

  • Typically develop within 48 hours of the prodromal symptoms

  • Usually, one parotid gland enlarges before the other, but unilateral parotitis occurs in 25% of patients

  • The parotid duct (orifice of Stensen) may be red and swollen

• Trismus may result from parotitis

• Involvement of other salivary glands (submaxillary and sublingual) occurs in 10% of cases

• Orchitis

  • Testes most common extra salivary disease site in adults

  • High fever, testicular swelling, and tenderness (unilateral in 75% of cases)

  • Usually develops 7–10 days after the onset of parotitis

Differential Diagnosis

• Swelling of the parotid gland may be due to

  • Calculi in the parotid ducts

  • Tumors

  • Cysts

• Parotitis may be produced by pyogenic organisms

  • Staphylococcus aureus

  • Gram-negative organisms

  • Drug reaction (phenothiazines, propylthiouracil)

  • Other viruses (HIV, influenza A, parainfluenza, EBV infection, coxsackieviruses, adenoviruses, HHV-6)

• Sarcoidosis

• Cirrhosis

• Diabetes

• Bulimia

• Pilocarpine usage

• Sjögren syndrome

• An elevated mumps-specific serum IgM is considered diagnostic

• Repeat testing 2–3 weeks after the onset of symptoms is recommended if the first assay is negative because the rise in IgM may be delayed

• Nucleic acid amplification techniques, such as real-time PCR, are more sensitive than viral cultures

• A fourfold rise in complement-fixing antibodies to mumps virus in paired serum IgG also confirms infection

• Anti-mumps IgM and IgG in the CSF can confirm the diagnosis of mumps-associated meningitis

• The virus can also be isolated from CSF early in aseptic meningitis

• Mild leukopenia with relative lymphocytosis may be present

• Elevated serum amylase usually reflects salivary gland involvement rather than pancreatitis

• Mild kidney injury is found in up to 60% of patients

• Symptomatic

• Topical compresses may relieve parotid discomfort

• Some clinicians advocate IVIG for complicated disease (eg, thrombocytopenia), although its definitive role is unproven

• There is no specific treatment for orchitis

Complications

• In the mumps outbreaks that occurred between 2006 and 2010 in the United States, complications from mumps were rare

  • Orchitis developed in 3.3–10% of adolescent and adult males

  • Lower abdominal pain and ovarian enlargement suggest oophoritis, which is usually unilateral and occurs in < 1% of postpubertal women

• Other rare complications, occurring in < 1% of cases

  • Meningitis

  • Encephalitis

  • Guillain-Barré syndrome

  • Hearing loss

  • Priapism or testicular infarction from orchitis

  • Pancreatitis

  • Thyroiditis

  • Keratitis

  • Neuritis

  • Hepatitis

  • Myocarditis

  • Thrombocytopenia

  • Migratory arthralgias

  • Nephritis

Prevention

• Vaccination is the most effective way to prevent mumps

• See Table 30–7

• Mumps vaccine component of the MMR is less effective than the measles and rubella components

  • One dose is 78% (range: 49–92%) protective

  • Two doses of the vaccine are 88% (range: 66–95%) effective

  • The CDC recommends a third dose in case of an outbreak

Prognosis

• The parotid glands return to normal within 1 week

• The entire course of mumps rarely exceeds 2 weeks

When to Refer

• Any suspect cases should be reported to public health authorities

When to Admit

• Trismus; meningitis; encephalitis; myocarditis; pancreatitis

• Severe testicular pain; priapism

• Severe thrombocytopenia