Intermediate Syndrome
Definition
Proximal muscle and respiratory weakness appearing 24 to 96 hours after acute organophosphate exposure, requiring mechanical ventilation, distinct from the acute cholinergic crisis and from delayed neuropathy.
- Cause
- Acute organophosphate exposure
- Onset
- 24 to 96 hours after exposure
- Presentation
- Proximal muscle and respiratory weakness
- Management
- Mechanical ventilation
- Distinct from
- Acute cholinergic crisis and delayed neuropathy
Common questions
Why is intermediate syndrome dangerous even after the acute cholinergic crisis resolves?+
Because it appears after the initial cholinergic symptoms have been treated and can seem like clinical improvement, respiratory and proximal muscle weakness can develop unexpectedly during this window, so patients require continued monitoring rather than early discharge.
How is intermediate syndrome distinguished from organophosphate-induced delayed neuropathy?+
Intermediate syndrome appears within days and involves muscle weakness with a good chance of recovery with ventilatory support, while delayed neuropathy appears one to three weeks later, involves peripheral nerve damage, and follows a different, often longer, recovery course.
Related terms
- Acetylcholinesterase (AChE)
- The enzyme that hydrolyses acetylcholine at cholinergic synapses. Inhibition by organophosphates or carbamates causes accumulation of acetylcholine at muscarinic, nicotinic and central...
- Aging
- The irreversible loss of one alkyl group from the phosphorylated AChE-organophosphate complex, after which oximes can no longer reactivate the enzyme. Aging...
- Anupam Verma Committee
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- DUMBBELS
- Mnemonic for the muscarinic side of the cholinergic toxidrome: Diarrhoea, Urination, Miosis, Bronchospasm and Bronchorrhoea, Bradycardia, Emesis, Lacrimation, Salivation.
- OPIDN
- Organophosphate-induced delayed polyneuropathy: a distal sensorimotor neuropathy appearing 2 to 3 weeks after exposure to certain OPs (TOCP, leptophos), mediated by neuropathy...
- Phosphine (PH3)
- The toxic gas liberated when aluminium phosphide reacts with water or gastric acid. It inhibits mitochondrial cytochrome c oxidase, generates reactive oxygen...