[Severe recurrent carbon monoxide poisoning caused by smoking]

Carbon monoxide (CO) is an odourless, colourless and toxic gas. Sources of CO include car exhaust, charcoal and tobacco smoke. CO binds to haemoglobin forming carboxyhaemoglobin (COHb). Heavy smokers have COHb levels up to 15%. There are reports of COHb levels of 24,2% caused by tobacco use and 28,7% after narghile smoking. A 54-year-old woman with schizophrenia was admitted at the intensive care unit with COHb levels as high as 35% caused by cigarillo smoking. She also presented with severe thiazide-induced hyponatriaemia and high haemoglobin levels.