Background: Paralytic poliomyelitis due to the wild-type poliovirus has been eradicated in the United States because of effective immunization programs. In the postvaccination era, most cases are caused by other RNA viruses, such as coxsackievirus or echovirus. The condition usually begins with a fever and upper respiratory tract or gastrointestinal tract symptoms that progress to a "paralytic" phase characterized by limb weakness, areflexia, and, occasionally, respiratory failure that superficially resemble Guillain-Barré syndrome.
Objective: To describe 2 patients with nonpoliovirus poliomyelitis and highlight the findings on magnetic resonance imaging of the spinal cord to distinguish these cases from variants of Guillain-Barré syndrome.
Design and setting: Case series from an academic medical center.
Patients: Following a viral illness, the patients, aged 35 and 50 years, had painless, progressive, asymmetrical weakness in the arms followed by respiratory failure in one patient, and generalized limb weakness in the other patient, reaching a nadir in 1 week. Both patients had fevers but no signs of meningitis at onset. Tendon reflexes were absent or reduced in affected regions. The cerebrospinal fluid findings were as follows: mononuclear leukocyte counts of 100 000 cells/mm(3) and 700 000 cells/mm(3), respectively, and the protein level was above 10 g/dL in both patients. Compound muscle action potential amplitudes were reduced in some nerves with active denervation in clinically affected muscles, and F-responses were absent but there were no other demyelinating features. Magnetic resonance imaging showed discrete T2-weighted signal changes of the ventral horns of the spinal cord, and one had elevated coxsackievirus titers in the serum. There was little recovery and significant atrophy in weak muscles after 3 years.
Conclusions: The poliomyelitis syndrome still occurs in adults in developed countries. It has superficial similarities to a motor axonal variant of Guillain-Barré syndrome but can be distinguished by clinical, cerebrospinal fluid, and, perhaps specifically, magnetic resonance imaging characteristics.