JIST

Abstract

Mortality in organophosphorus compound (OPC) poisoning is mainly due to respiratory arrest as an end result of respiratory muscle paralysis. Associated hypokalaemia compounds the weakness. Potassium is firmly balanced in urinary excretion. Ratio between intracellular and extracellular potassium concentration plays a fundamental role in cell membrane resting membrane potential (RMP) maintenance. A relatively small change in extracellular potassium concentration can significantly alter RMP and functional activity.

This study is aimed at evaluating the significance of hypokalaemia in acute OPC poisoning and its implications as a predictor of morbidity and mortality. It is a 6-month, cross-sectional study, which included all cases admitted with a history of consumption of OPC, and confirmed at the Poison Detection Center, with exclusion of patients aged more than 60 years, presence of severe vomiting, and associated chronic illnesses, such as renal and cardiac failure. Serum potassium concentration was prospectively measured and tabulated along with associated clinical signs.

The study revealed that potassium homeostasis appears to be altered in acute OPC poisoning, which in turn alters neuromuscular junction activity. Gradual fall in potassium concentration produces serious clinical features, including muscle fasciculations, twitching, convulsions, respiratory distress and death. The severity of these was directly proportional to the reduction in the potassium level.