[Carbon monoxide poisoning due to lack of maintenance of a natural gas boiler].

Carbon monoxide causes one third of all poisoning deaths in Denmark, but is probably grossly underdiagnosed. We present a case where an elderly couple was admitted on several occasions to local hospitals with a variety of symptoms and signs; e.g. flu-like symptoms, generalized seizures, polycythaemia, chest pain, and ventricular tachycardia. The correct diagnosis, carbon monoxide poisoning, was made when the dog in the family was found dead; examination of the natural gas boiler revealed sooting, clogging of the flue, and a carbon monoxide concentration above 0.2 percent. The natural gas boiler had not been checked after installation five years earlier. Natural gas installations are becoming still more prevalent in Danish homes, but present regulations regarding the installations are apparently not yet able to prevent new incidents of carbon monoxide poisoning.