Mumps Workup

Updated: Jan 17, 2019
  • Author: Germaine L Defendi, MD, MS, FAAP; Chief Editor: Russell W Steele, MD  more...
  • Print

Approach Considerations

Mumps is a clinical diagnosis. A study investigated the difficulty of medical professionals to diagnose mumps, noting that only 14% of 2082 cases occurring during an outbreak could be confirmed by laboratory sera testing. [19] This study concluded that the examiner's ability to diagnosis mumps as based solely on clinical presentation was low.


Laboratory Studies

Serum amylase is elevated in mumps parotitis (amylase-S) and in pancreatitis (amylase-P). Serum lipase is elevated in pancreatitis.

A complete blood cell (CBC) count reveals a normal, decreased, or elevated white blood cell (WBC) count, with the differential reflecting a relative lymphocytosis. Sera inflammatory markers, such as C-reactive protein or erythrocyte sedimentation rate (ESR), can be elevated to reflect a nonspecific systemic inflammatory response.

Viruria is present, even in uncomplicated cases, with the mumps virus detected in urine within the first 2 weeks of illness. [20]

Mumps virus can be isolated from nasopharyngeal swabs, blood, and fluid from the buccal cavity typically within the window of 7 days before, up until 9 days after, the onset of parotitis. The virus can also be isolated in a cell culture inoculated with throat washings, urine, or spinal fluid. CNS involvement usually shows a lymphocytic pleocytosis. Polymerase chain reaction (PCR) assay of the CSF can be used to detect viral mumps RNA and fosters a rapid confirmation modality for the diagnosis.

Mumps infection can be confirmed by a positive mumps-specific immunoglobulin M (IgM) titer or by demonstration of a significant rise in mumps-specific immunoglobulin G (IgG) antibody titers between acute and convalescent sera specimens.  IgG titers can be detected by complement fixation, hemagglutination inhibition, or enzyme immunoassay. Interpretation of titer rise may have limitations due to potential mumps cross-reaction with other parainfluenza viruses. [21]


Imaging Studies

No specific imaging studies are diagnostic for mumps infection.

Imaging studies may be needed to further evaluate certain complications associated with mumps infection. If concern exists for meningitis or encephalitis, head computed tomography (CT) scanning without contrast should be considered, prior to lumbar puncture procedure to obtain CSF.

Scrotal ultrasonography must be performed when orchitis is clinically suspected, with specific focus to rule out testicular torsion.


Other Tests

Complicated cases may require further testing to determine additional organ involvement.

Given the association between mumps infection and sensorineural hearing loss, auditory testing is indicated to assess for development of a hearing impairment.

If diagnostic clues for meningitis or encephalitis are present, a lumbar puncture to obtain CSF must be strongly considered to clarify cause.