Carbon monoxide poisoning

We studied the clinical profile and autopsy findings of carbon monoxide (CO) poisoning encountered at a hospital located at the altitude of 5,000 ft above mean sea level.

Clinical and postmortem findings in 25 and 15 cases of accidental CO poisoning respectively were evaluated. The diagnosis was made on circumstantial evidences, definite history of "Bukhari" burning and positive Kunkel's test for carboxyhaemoglobin (COHb). Detailed routine investigations including pulse oxymetry, X-ray chest and electrocardiographical monitoring was carried out in all the 25 patients. Oxygen (100%) via an endotracheal tube in all the comatosed patients and by conventional non-rebreathing plastic face masks was the mainstay of treatment. All patients were monitored and followed up for any delayed neurological sequelae.

Most of the patients were young adults and the duration of exposure varied between three to eight hours. The initial diagnosis was stroke in three, seizure in one, encephalitis in two and ischaemic heart disease (IHD) in four. Neurological and respiratory signs and symptoms were noted in 19 and 18 of 25 patients respectively. SPO2 measured by pulse oxymetry was normal in all cases. ECG was suggestive of IHD in four patients. No delayed neurological sequelae was noted in any patients. Autopsy revealed deep red discoloration of skin and serous membranes in 80%, pulmonary oedema in 100% and cerebral oedema with widespread multiple pin point haemorrhages mainly in thalamus and globus pallidus in 40%.

A high level of suspicion and routine history about the kind of indoor heating, specially in cold climate areas during winter will help in early diagnosis and decrease the incidence of misdiagnosis of CO poisoning. Oxygen (100%) or hyperbaric oxygen, if available should be administered without waiting for COHb levels to decrease morbidity and mortality.