A 40-year-old farmer presents 3 weeks after an episode of acute organophosphate poisoning with progressive weakness of the proximal muscles of the lower limbs, followed by distal weakness and foot drop. Sensory examination is normal. This condition is mediated by inhibition of which enzyme?

• A Acetylcholinesterase
• B Butyrylcholinesterase
• C Monoamine oxidase
• D Neuropathy target esterase (NTE) ✓

Explanation

Organophosphate-induced delayed neuropathy (OPIDN) occurs 1-4 weeks after acute exposure and is caused by inhibition of neuropathy target esterase (NTE) in the nervous system, leading to distal axonal degeneration of long, large-diameter motor and sensory neurons. It spares the CNS. Acetylcholinesterase inhibition causes the acute cholinergic crisis, not delayed neuropathy. The absence of sensory loss with motor-predominant findings is characteristic of OPIDN.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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