Mumps–It’s Back!

PATIENT PRESENTATION
Parotitis is the classic (but not universal) physical exam finding in mumps. Parotid gland inflammation causes generalized swelling anterior to the ear and inferior to the mastoid process, with jaw angle obliteration (see Figure 1).⁹ If only one parotid gland is involved, the patient’s face appears asymmetric. Other significant exam findings may include fever and erythematous swelling of the Stensen (parotid) duct.¹⁰

Nonspecific symptoms—including respiratory symptoms, myalgia, anorexia, malaise, headache, and low-grade fever—may occur in more than 50% of cases.⁸ CNS involvement may cause nuchal rigidity (stiff neck). In postpubertal males, testicular swelling and/or induration, pain, tenderness, and enlarged inguinal lymph nodes may be present.

Mumps can be challenging to diagnose based on clinical presentation alone; for example, parotitis occurs in only 30% to 40% of cases.⁸ Other viruses, such as parainfluenza virus 1 and 3, coxsackievirus, adenovirus, influenza A, cytomegalovirus, and HIV, can also cause swelling of the parotid glands, but mumps is the only virus known to cause parotitis on an epidemic scale.⁴ Furthermore, up to 20% of cases may be asymptomatic.^8,11 Because mumps is highly contagious, a history of exposure to an affected individual is a compelling factor in making the diagnosis.

The incubation period for mumps is 12 to 25 days, with parotitis usually developing 16 to 18 days after exposure.⁴ This relatively lengthy incubation period increases the likelihood of viral spread. The virus is contagious from three days prior to symptom onset to day 4 of active disease.⁸ To prevent disease transmission, it is recommended that individuals remain isolated from others until five days after the onset of salivary gland swelling.⁴

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