01292nas a2200253   4500000000100000008004100001260001300042653001500055653001300070653001200083653001100095653003300106653000900139653002200148100001100170700001500181700001600196700001200212245007600224300001000300490000700310520070700317022001401024       1987                            d  c1987 Jan10aAdolescent10aCyanosis10aDapsone10aHumans10aIntraoperative Complications10aMale10aMethemoglobinemia1 aMayo W1 aLeighton K1 aRobertson B1 aRuedy J00aIntraoperative cyanosis: a case of dapsone-induced methaemoglobinaemia.  a79-820 v343 a<p>Intraoperative cyanosis is most commonly caused by hypoxaemia. The anaesthetist is required to perform a rapid series of diagnostic manoeuvres and take remedial action. Occasionally methaemoglobin, sulfhaemoglobin, or haemoglobin M, undetected preoperatively, is the cause of the cyanosis. We report a case of methaemoglobinaemia secondary to dapsone ingestion that was diagnosed intraoperatively. Dapsone, a sulfone, is used therapeutically to treat leprosy and dermatitis herpetiformis. The differential diagnosis of cyanosis, and the origin and fate of methaemoglobin are discussed. In addition the diagnostic steps and the laboratory investigations required to make the diagnosis are listed.</p>  a0832-610X