[Pseudomigraine as a symptom of carbon monoxide intoxication]

Carbon monoxide poisoning (CO) is a common intoxication. Diagnosis is sometimes difficult since the symptoms may be very varied. We report a case of repeated intoxication which led to several consultations and admission to hospital, since there were headaches and loss of consciousness suggesting basilar migraine.

A 30 year old woman consulted for repeated headaches over the previous six months, normally occurring in the morning, accompanied by vertigo, nausea and vomiting and loss of consciousness on two occasions. Clinical examination and the complementary tests done (laboratory analysis, cerebral MR, ECG, ECG Holter, EEG) were normal. Finally CO intoxication was diagnosed when levels of carboxyhemaglobin of over 30% were found in both the patient and her sister. The cause was a faulty water heater, confirmed on technical inspection.

CO intoxication may present as repeated headaches, with or without alteration in consciousness. Finding similar symptoms in other people living in the same place should increase suspicion. In certain case, anamnesis should include details regarding apparatus used for heating, cooking and bathrooms. More carboxyhaemaglobin estimations should be done in Emergency Departments.