A man in his sixties with acute chest pain.

BACKGROUND

Chest pain is a frequent symptom of acute myocardial infarction, but the cause is not always coronary atherothrombosis. We present a case where the patient himself had made a correct non-cardiac diagnosis, but this was initially overlooked by the doctor.

CASE PRESENTATION: A man with a history of cardiac infarction was admitted with acute chest pain and troponin elevation. Electrocardiogram suggested ST elevations, echocardiography showed a possible slight hypokinesia, and we primarily suspected an acute coronary syndrome. However, invasive coronary angiography was negative and a primary acute myocardial infarction was less likely. A renewed interview revealed that the patient had worked with a propane burner indoors without adequate ventilation. The patient himself suspected carbon monoxide poisoning. Arterial blood gas showed HbCO 27.4 %, which was unfortunately overlooked initially. The patient had carbon monoxide poisoning with symptoms of dizziness, hand ataxia and myocardial ischaemia. He received 100 % oxygen and HbCO was normalised.

INTERPRETATION: The imbalance between oxygen demand and supply resulted in a type 2 cardiac infarction. A thorough medical history is crucial for correct diagnosis but can unfortunately be missed on a busy shift. This case illustrates the importance of the patient's own diagnostic assumption.