Factors Associated with Mortality of Myxedema Coma: Report of Eight Cases and Literature Survey

High-dose thyroid hormone replacement has been recommended for treatment of myxedema coma (MC) while questions of safety of the therapy and of efficacy of low-dose thyroid hormone replacement have not been systematically addressed. We treated 8 patients with MC in a period of 18 years, the first 3 with high-dose intravenous injections of levotriiodothyronine (LT 3 ) and the other 5 patients with a smaller amount of either LT 3 or levothyroxine (LT 4 ). Two of the first 3 patients died of pneumonia and the other 5 recovered despite pulmonary abnormalities at the outset. To find factors associated with fatal outcome after treatment, the MEDLINE database was searched for MC cases with data of thyroid hormone replacement and outcome within 1 month of therapy. Clinical data for our 5 patients and 82 cases from the MEDLINE search were pooled and factors associated with mortality were sought among age, gender, presence of cardiac or pulmonary complications, and doses of thyroid hormone by multiple logistic regression analysis. It revealed that greater age, cardiac complications, and high-dose thyroid hormone replacement (LT 4 ≥ 500 μg/d or LT 3 ≥ 75 μg/d) were significantly associated with a fatal outcome within 1 month of treatment. Elderly MC patients can be treated with low-dose hormone replacement. A bolus of 500 μg LT 4 , especially by mouth or via nasogastric tube, appears to be tolerated by younger patients (