Retinal hemorrhages in subacute carbon monoxide poisoning. Exposures in homes with blocked furnace flues.

Three incidences of carbon monoxide poisoning occurred owing to defective heating systems. Twelve persons were affected; of these, three lost their lives. Because the symptoms of carbon monoxide poisoning closely resemble flu and other common illnesses, correct diagnosis was not made as promptly as it might have been. Hemorrhages were found in the nerve fiber layer of the retina in all five of the patients who had been exposed for more than 12 hours. It is our contention, therefore, that complete examination of the patient should always include ohthalmoscopy, and that the finding of retinal hemorrhages, in addition to nausea, headache, and dizziness, should aler the physician to the possibility of carbon monoxide poisoning.