FATAL MYXEDEMA, WITH AND WITHOUT COMA

Abstract

Fatal myxedema and myxedema coma, although described in the early years of thyroid investigation, have since received little recognition until recent reports of approximately 30 cases. These patients are characteristically myxedematous in appearance. The average age has been 60 years with a predominance of females. They present in coma or with severe lethargy. The majority of patients have had a temperature below 95[degree]F and all but one case has occurred in the winter months. The definitive diagnosis is frequently dependent upon the low serum protein bound iodine level or radioactive I131 uptake of the thyroid. The laboratory abnormalities most frequently noted, other than those related to thyroid function, were hyponatremia and hyperkalemia. The mortality rate of myxedema coma has been over 80%. Replacement therapy has varied from small amounts of desiccated thyroid to large amounts of parenteral triiodo-thyronine or thyroxine. The surviving cases were generally those with less severe electrolyte and temperature derangements who were given parenteral thyroid substances. The frequency of this complication is emphasized by the observation of 5 patients with severe myxedema in the past 3 years of whom only 1 responded to replacement therapy. All of the present cases were elderly females with a long history of myxedema. One patient in coma died without showing a response to terminal replacement with small amounts of parenteral triiodothyronine. The one surviving case became hypothermic and lapsed into semi-coma during the summer months. She showed a marked response to relatively large doses of parenteral triiodothyronine. The remaining cases, although severely myxedematous, had concomitant disease processes as their immediate cause of death. Replacement therapy with small doses of parenteral triiodothyronine or desiccated thyroid had no effect on their clinical picture. The use of parenteral triiodothyronine is advised in these patients, and if the patient shows no response to small doses, the amount administered should be progressively and rapidly increased. Although a number of patients have received glucocorticoids without proven benefit, their use is rational and should be continued until definite contraindications are proven. CO2 narcosis should be treated if present.