Cholinergic toxidromes

In cholinergic syndromes, the presenting signs and symptoms are related to the build-up of acetylcholine (ACh) in the voluntary and autonomic nervous systems and the characteristic toxidrome has been described for many years. Most cases have been following pesticide exposure or pesticide self-poisoning, but there is also information about accidental and deliberate release of nerve agents. 

The following simple acronyms are commonly used to describe the signs and symptoms of organophosphate exposure. 

Lachrymation—with the formation of uncontrollable tears Urination— uncontrolled urinary incontinence Defecation— uncontrolled with diarrhoea Gastrointestinal upsets—with abdominal cramps Emesis 

Note that this simple acronym does not include the following features of anticholinesterase intoxication  

Bradycardia (from vagal stimulation although tachycardia is more common) MTWHF (relating to overstimulation of nicotinic receptors) 

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Key Practice Points Although the cholinergic toxidromes are a useful guide in... 

The appearance of individual features of the cholinergic toxidrome is dependent... 

Miosis occurs at levels of OP exposure which may not give rise to other features of the cholinergic toxidrome other than a tight chest and runny nose. 

Toxic syndromes ( toxidromes ) are clinical syndromes that are essential for the successful recognition of poisoning patterns. A toxidrome is the constellation of clinical signs and symptoms that suggests a specific class of poisoning. The most important toxidromes are (1) anticholinergic, (2) cholinergic, (3) opioid and opioid withdrawal, (4) sedative-hypnotic and sedative-hypnotic withdrawal, and (5) sympathomimetic. Symptoms for these toxidromes are listed in Table 34-2. 

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