Canadian Journal of Anesthesia, Vol 41, 969-972, Copyright © 1994 by Canadian Anesthesiologists' Society

ARTICLES

Thyrotoxicosis factitia in a post-aortocoronary bypass patient

C Redahan and JM Karski
Department of Anaesthesia, Toronto Hospital, University of Toronto, Ontario, Canada.

A 52-yr-old man presented with an evolving myocardial infarction and unstable angina. Previously, he had undergone aortocoronary bypass surgery for triple vessel disease and at that time was diagnosed as hypothyroid. He had been refractory to thyroxine treatment and now required 0.3 mg thyroxine daily. On admission, he was hypertensive, tachycardic and found to be thyrotoxic secondary to excess thyroid hormone ingestion. Treatment with iopanoic acid was started. Despite medical therapy he continued to have unstable angina. Coronary angiography confirmed further triple vessel disease with blockage to his previous grafts. He was taken to surgery for coronary revascularization. On arriving in the intensive care unit he developed a thyroid storm. His temperature increased from 36.5 to 39.5 degrees C requiring a cooling blanket and cold irrigation down a nasogastric tube. An esmolol infusion was started to control his persistent tachycardia but this depressed his myocardial contractility. He required amrinone and noradrenaline infusions as further inotropic support. For sedation and muscle relaxation, intravenous propofol infusion and doxacurium were given. Over the following 20 hr the patient's condition stabilized. In conclusion, we describe the use of a short-acting beta blocker to avoid compromising an impaired myocardium during a thyroid storm which we could stop if the patient's cardiac condition deteriorated. In addition, amrinone, a phosphodiesterase inhibitor, was our inotrope of choice as it does not act on the already blocked beta adrenergic system.