Acute Poliomyelitis Workup

Updated: Jul 13, 2022
  • Author: Stephen Kishner, MD, MHA; Chief Editor: Stephen Kishner, MD, MHA  more...
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Laboratory Studies

See the list below:

  • Order lumbar puncture test.

    • Cerebrospinal fluid (CSF) pressure may be increased.

    • Pleocytosis (neutrophils in the first few days, then lymphocytes) may be noted in the CSF during the period before onset of paralysis in acute poliomyelitis.

    • The CSF protein content may be elevated slightly with a normal glucose, except in patients with severe paralysis, who may demonstrate protein elevations to 100-300 mg/dL for several weeks.

  • Order a complete blood count (CBC), because leukocytosis may be present.

  • Perform virus recovery from throat washing, stool culture, blood culture, and CSF culture. Viral studies in stool specimens are essential for the diagnosis of poliomyelitis. To increase the probability of isolating poliovirus, it is recommended that two stool specimens be collected 24 hours apart. [16]

    • Recover virus from throat washing during the first week and stool culture from the first 2-5 weeks.

    • In rare cases, the virus may be isolated from CSF or serum, in contrast to the paralytic illnesses caused by other enteroviruses.

    • These tests require additional demonstration of a 4-fold rise in the virus antibody titer to make a specific diagnosis.

  • Polymerase chain reaction (PCR) assay is routinely used to differentiate wild-type strains from vaccine strains.


Imaging Studies

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  • Magnetic resonance imaging (MRI) may show localization of inflammation to the spinal cord anterior horns.



See the list below:

  • Electromyography

    • The earliest electromyographic finding in poliomyelitis is a reduction in the recruitment pattern and a diminished interference pattern due to acute motor axon fiber involvement.

    • Fibrillations develop in 2-4 weeks and persist indefinitely; fasciculations also may be observed.

    • Motor unit action potentials initially have decreased amplitude and then become large in amplitude with increased duration. Later, polyphasic motor units are observed because of nerve reinnervation.

    • The motor nerve conduction velocities remain within normal limits; however, the compound muscle action potential (CMAP) is reduced in direct proportion to the number of motor axons that are affected. Sensory nerve conduction studies remain within normal parameters, due to sparing of the dorsal root ganglion.


Histologic Findings

Under microscopy, the spinal anterior horn cells are surrounded by inflammatory cells. Spongiosis of the gray matter, containing many scattered inflammatory cells, also is noted. Most inflammatory cells are neutrophil leukocytes.


Other Tests

A study by Brehm et al indicated that in polio survivors, the 6-minute walk test (6MWT) and the 6-minute walking energy cost test (WECT) are dependable means of evaluating walking capacity, with the test-retest reliability of both considered excellent. The tests are not interchangeable, however; the study recommended that the 6MWT be used to assess maximal walking capacity and the WECT be employed to measure submaximal walking capacity. The investigators also reported that the sensitivity of the 6MWT in detecting change for walked distance is slightly greater than that of the WECT. [17]