Arsine gas poisoning: the importance of exchange transfusions in severe cases.

Arsine (arsineuretted hydrogen, AsH3) was first identified in 1775. It is a colourless, non-irritant gas that smells like garlic. After the initial demonstration of its toxicity in 1815,454 cases of poisoning had been documented by 1974. * To date, a further 16 cases have been described,2"5 including one with per manent renal damage.6 Many cases probably go un recognised as the attending medical staff may not be aware of the possibility of arsine gas poisoning. This may lead to delay in the diagnosis and management with increased mortality and morbidity. The prognosis of patients exposed to arsine gas de pends on the effect on renal function. Previously anuria was a common cause of death but, with dialy sis, patients should not die from renal failure. A prob lem arises with the adequate removal of arsine and its associated toxic complexes. In this respect dialysis alone is insufficient, and only the removal of the ar sine haemoglobin haptoglobin complex by exchange transfusion will stop the toxic process. Several causes for the renal failure have been postu lated by Muehrcke and Pirani.7 Firstly, arsine gas it self has a direct toxic effect on renal tissue. Secondly, as a result of haemolysis, haemoglobinuric casts may precipitate in the tubules resulting in tubular damage. Finally, the oxygen carrying capacity of blood is reduced by haemolysis and thus hypoxic damage to renal tissue may occur. The case we describe is of a worker at a metal refinery near Johannesburg; he was one of five cases of arsine poisoning seen at Johannesburg Hospital over the past six years. Methods