Chapter 49 - Management of Organophosphorus Pesticide Poisoning

Abstract

The successful management of organophosphorus (OP) pesticide poisoning depends on: the clinician possessing an understanding of the mechanisms of OP pesticide toxicity and applying them to the treatment options; accurate diagnosis and assessment of the severity of intoxication; maintenance of vital body functions and adequate clinical monitoring; further absorption of the OP pesticide being minimized; and appropriate use of atropine, oxime, and diazepam. The chemical structure of OP pesticide and the presence of other ingredients in the formulation may have an impact on the speed of onset of features of intoxication. In addition, the fact that many OP insecticides are lipophilic means that they are distributed to and stored in body fat, and therefore, elimination takes place slowly. The severity of intoxication may increase for 12–36 hrs after exposure, intoxication may be prolonged, or relapse may occur after apparent clinical recovery. An understanding of the toxicodynamic aspects also explains why oximes may be of particular value in intoxication because of diethyl phosphates. The diagnosis of OP pesticide poisoning is based on a patient's history, clinical presentation, and laboratory tests. Maintenance of vital body functions and adequate clinical monitoring, and minimizing further absorption of OP pesticide are two management proceses. A number of novel approaches to antidotal treatment of OPs have been studied, often using prophylactic protocols and mostly in relation to nerve agent poisoning, but some may be applicable, at least in principle, to OP pesticide poisoning.