Clinical and etiological profile of tropical ataxic neuropathy in Kerala, South India.

Background/aims: Very little is known about the occurrence of tropical ataxic neuropathy (TAN) from southern India. This study describes the clinical spectrum of TAN from Kerala, southern India, and explores its etiology.

Methods: We reviewed the clinical and laboratory profile of 40 TAN cases diagnosed in a tertiary referral center in central Kerala. We enquired the consumption of cassava foods and estimated the thiocyanate levels in the serum, urine and sural nerve.

Results: The notable demographic characteristics included female preponderance, peak age at onset in the thirties, rural residence and poor socioeconomic status. The diet in the majority comprised a large amount of tapioca, which is low in protein. In addition to sensory peripheral neuropathy, 90% had decreased hearing, 50% had decreased vision, and 25% had spasticity involving the lower extremities. None had signs of overt vitamin deficiencies or malabsorption syndrome. Compared to the controls, the serum, urine and sural nerve thiocyanate levels were significantly elevated in the patients. With cessation of cassava intake and better nutrition, improvement in the neurological disability occurred in the majority.

Conclusions: This study, for the first time, provides evidence for the occurrence of TAN in south India and the possible etiological role of cassava intake.