A patient presents with bradycardia, bronchospasm, miosis, urinary incontinence, and excessive lacrimation after agricultural work. Which enzyme's inhibition most directly explains the urinary incontinence in this cholinergic toxidrome?
- A Monoamine oxidase
- B Acetylcholinesterase ✓
- C Pseudocholinesterase in plasma only
- D Catechol-O-methyltransferase
Correct answer: B. Acetylcholinesterase
Explanation
Organophosphate pesticides irreversibly inhibit acetylcholinesterase (AChE), allowing acetylcholine to accumulate at all cholinergic synapses. Excess ACh at M3 receptors of the detrusor muscle causes sustained bladder contraction, producing urinary incontinence as part of the SLUDGE/DUMBELS syndrome. Plasma pseudocholinesterase hydrolyses succinylcholine rather than mediating this effect; MAO and COMT degrade catecholamines and are not involved.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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