Clinical Management of Acute OP Pesticide Poisoning

Abstract

Organophosphorus pesticide (OP) poisoning is a worldwide problem. OPs inhibit various enzymes, in particular acetylcholinesterase (AChE) which is considered the key action that induces the clinical features of OP poisoning known as acute cholinergic syndrome. Multisystem clinical features are noted with most cases of OP poisoning but the manifestations can differ between individual OP compounds. Proper medical treatment follows an initial diagnosis, which in turn requires a high index of suspicion. If required, OP exposure can be confirmed by quantifying the blood or plasma cholinesterase activity. Standard resuscitation and supportive care is essential in the management of the exposed patient. This is accompanied by rapid administration and dose titration of antagonists of muscarinic cholinergic receptors (anti-muscarinics, notably atropine). A detailed risk assessment should be conducted so that adverse outcomes can be anticipated and treated, where possible. The risk of secondary poisoning in staff providing health care to patients is anticipated to be low if standard precautions are exercised. Other treatments are available but their role is more controversial; indeed, use varies across the world. For example, oximes such as pralidoxime and obidoxime appear to have the ability to reverse AChE inhibition in patients. However, clinical trials have yielded conflicting results (both benefit and harm), so their role in routine clinical practice is not confirmed. The role of oximes and other treatments such as magnesium, bicarbonate, clonidine, nicotinic antagonists, and extracorporeal blood purification modalities are the areas of research interest. Careful monitoring and development of a discharge plan are also necessary to optimise outcomes.