Acute ataxic neuropathy: a clinical, electrophysiological and morphological study.

Sensory ataxia as the chief manifestation of acute neuropathy is rather rare. Of the 224 cases of acute polyneuropathy seen over 6 years (1984-1990) only 10 patients (M:F 3:7) had disabling ataxia as the presenting feature. Their ages ranged from 14-61 years. Antecedent febrile illness was present in 6 patients and the peak deficit evolved over 2-25 days. Severe ataxia, paresthesia, distal areflexia and predominant joint sense loss were common to all, motor weakness was either absent or insignificant. CSF was acellular and revealed elevated protein in 3 subjects. All patients had electrophysiological evidence of severe sensory neuropathy with mild or no motor neuropathy. Sural nerve biopsy in one patient showed loss of large, as well as small, diameter myelinated fibres, secondary demyelination, but no evidence of inflammation. At follow up marginal to moderate improvement in ataxia was noted in only 5 patients. Absence of ophthalmoplegia and motor weakness, poor prognosis and characteristic electrophysiological and histopathological observations suggest that acute ataxic neuropathy may be a distinct entity.