Fatal methaemoglobinaemia induced by self-poisoning with sodium nitrite.

Inadvertent ingestion of sodium nitrite is known to precipitate metheamoglobinaemia. No cases exist, however, of intentional suicide by methaemoglobinaemia following self-poisoning with sodium nitrite. A 76-year-old man collapsed and rapidly developed brady-asystolic cardiac arrest 25 min following self-poisoning with an unknown quantity of crystalline sodium nitrite. On arrival in the ED the patient was asystolic with cardiopulmonary resuscitation in progress. Haemoglobin concentration was 110 g/L, arterial methaemoglobin measured 82.6% and serum lactate 9.6 mmol/L. Antioxidative treatment was undertaken with total 5 mg/kg intravenous methylene blue administered in divided aliquots. Despite prolonged resuscitative efforts the patient died. Resuscitation from methaemoglobinaemia-induced asystole following self-poisoning presents a unique therapeutic challenge. Treatment of methaemoglobinaemia-induced cardiovascular instability and overt cardiopulmonary arrest are discussed.