Organophosphate poisoning

Poisoning can occur due to occupational or accidental exposure, deliberate ingestion, or chemical warfare with nerve gases.

Presentation is highly variable due to differences in dose, agent toxicity, and type of exposure.

Diagnosis is usually based on a history of exposure, with characteristic signs of cholinergic excess, but can be difficult when the patient is inadvertently exposed or is unconscious or confused.

Standard treatment is resuscitation, supportive care, decontamination, and use of atropine.

Accidental or occupational exposures nearly always have a favourable outcome.

Poisoning occurs after dermal, respiratory, or oral exposure to either organophosphate pesticides (e.g., chlorpyrifos, dimethoate, malathion, parathion) or nerve agents (e.g., tabun, sarin), causing inhibition of acetylcholinesterase at nerve synapses. The term organophosphate poisoning only applies to those organophosphates that inhibit acetylcholinesterase. This topic focuses on pesticide poisoning.