Which symptom cluster is most associated with organophosphate poisoning?

• A. Cholinesterase inhibition symptoms: salivation, lacrimation, urination, defecation, GI distress, emesis; plus sweating and muscle weakness.
• B. Respiratory distress only with no other symptoms
• C. Skin rash and itching
• D. Hearing loss and vertigo

Answer: (A)

Organophosphate poisoning causes a cholinergic crisis because these compounds inhibit acetylcholinesterase, the enzyme that breaks down acetylcholine. With acetylcholine accumulating at both muscarinic and nicotinic receptors, you get a characteristic set of symptoms driven by excessive parasympathetic activity and neuromuscular effects. The classic cluster includes increased secretions and GI activity (salivation, tearing, urination, defecation, abdominal cramping, vomiting) along with sweating, and muscle weakness from nicotinic stimulation. The combination of these muscarinic and nicotinic signs is the hallmark of organophosphate exposure.

Other options don’t fit this pattern. Respiratory distress can occur but usually accompanies the other cholinergic signs rather than standing alone as the sole symptom. Skin rash and itching point toward an allergic or dermatologic reaction, not acetylcholinesterase inhibition. Hearing loss and vertigo aren’t typical features of acute organophosphate poisoning, which centers on widespread cholinergic overactivity rather than vestibular symptoms.