INTRODUCTION: Organophosphate esters are widely used both in agriculture and in 
industry and may give rise to acute intoxication due to their direct 
anticholinesterase effect. Less often a polyneuropathic syndrome of late onset 
may occur. This is predominantly motor, symmetrical, with muscle atrophy and 
pyramidal signs. These neurotoxic features are due to inhibition of the target 
esterase of this neuropathy. Histopathological studies show axon degeneration of 
'dying back' type.
CLINICAL CASE: We present the case of a 24 year old man with severe sensomotor 
neuropathy, predominantly distal, with marked atrophy of the interosseus 
muscles, claw hand and foot drop, together with increased deep tendon reflexes. 
This patient had worked on the land, cultivating maize, from the age of 14, when 
his symptoms began and became progressively worse. On electromyography there was 
sensomotor peripheral polyneuropathy, which was primarily axonal and 
predominantly motor and distal. Peripheral nerve biopsy confirmed the presence 
of 'dying back' type axonopathy. Extensive biochemical investigations ruled out 
other causes of polyneuropathy. Cerebral resonance study was normal.
CONCLUSIONS: Agricultural workers chronically exposed to organophosphate 
insecticides, without adequate protection, have an increased risk of developing 
late onset neuropathy due to organophosphates. The risk of developing late onset 
neuropathy is not necessarily related to a history of acute intoxication, since 
chronic sublethal exposure may mean that previous acute anticholinergic symptoms 
pass undetected.