Hydroxocobalamin-related Purple Chromaturia: A Sequela of Treating Cyanide Poisoning

Cyanide poisoning is uncommon and many junior doctors are unaware of its presentation and treatment. We illustrated a case of a 37 years old gentleman presented with headache and multiple episodes of vomiting after a suicide attempt by ingesting cyanide salts. He manifested signs of acute cyanide poisoning such as hypotension, a raised lactate level and disorientation. In view of the strongly suggestive history, he was quickly given intravenous hydroxocobalamin as the antidote in the emergency department. Two hours after the infusion, purple chromaturia was noted. This is one of the adverse effects of hydroxocobalamin and the urine discolouration may last up to weeks after the initial treatment. Recognition of this adverse effect is essential to reassure patients and avoid unnecessary investigations.