N-hexane neuropathy in screen printers.

BACKGROUND To study the clinical and electrophysiological profile of n-hexane neuropathy in a tertiary care center of India. METHODS Twenty five screen printers from five different factories, with peripheral neuropathy were included in the study. A detailed general physical, systemic and neurological examination was conducted Visual acuity, color vision and field charting was done in all the subjects. All patients were subjected to Folstein mini mental scale examination. Electrophysiological evaluation included motor and sensory conduction studies of the conventionally studied nerves of upper and lower limbs, Needle EMG of various distal and proximal muscles and patterned visual evoked responses. The electrophysiological profile was repeated every three months till one year. Sural nerve biopsy was studied in six patients. The patients were followed for a maximum of 4 years. RESULTS Twenty three [92%] patients had sensory- motor neuropathy, while pure sensory neuropathy was seen in two. The sensory conductions were affected almost equally in upper as well as the lower limbs, while the motor conductions were affected more in the lower limbs than the upper limbs. The sensory conductions were not recordable in both the upper and the lower limbs in 18 [72%] patients. Motor conduction studies revealed an asymmetric and patchy involvement. Proximal conduction block was seen in 3 patients [12%]. On needle EMG features of denervation were seen in all patients. P100 latency was normal in all. Sural nerve biopsy showed a selective decrease in large myelinated axons with demyelination. Axonal swelling with focal areas of demyelination was observed in two patients. CONCLUSIONS The electrophysiological patterns as well as the histopathology reflect the pathophysiology of n-hexane neuropathy.