[Clinical Picture] Chocolate-coloured serum in methaemoglobinaemia
A 53-year-old man presented to the emergency department of our hospital in January, 2014, after a syncopal episode. He was a regular smoker and recreational drug user, and had taken heroin, cannabis, and benzodiazepine during that week. He had a history of glucose-6-phosphate dehydrogenase (G6PD) deficiency. On examination he had grey pallor and was dyspnoeic at rest (respiratory rate 23 breaths per minute). His oxygen saturation was 70% on 100% inspired oxygen and his blood sample, which showed anaemia (haemoglobin 54 g/L; normal 130–180 g/L), was chocolate brown (figure).