- Douglas S Ross, MD
Douglas S Ross, MD
- Section Editor — Thyroid Disease
- Professor of Medicine
- Harvard Medical School
Myxedema coma is defined as severe hypothyroidism leading to decreased mental status, hypothermia, and other symptoms related to slowing of function in multiple organs. It is a medical emergency with a high mortality rate. Fortunately, it is now a rare presentation of hypothyroidism, likely due to earlier diagnosis as a result of the widespread availability of thyrotropin (TSH) assays.
Early recognition and therapy of myxedema coma are essential. Treatment should be begun on the basis of clinical suspicion without waiting for laboratory results. Important clues to the possible presence of myxedema coma in a poorly responsive patient are the presence of a thyroidectomy scar or a history of I-131 therapy or hypothyroidism. A history obtained from family members often reveals antecedent symptoms of thyroid dysfunction followed by progressive lethargy, stupor, and coma.
The clinical presentation, diagnosis, and treatment of myxedema coma will be reviewed here. The diagnosis and treatment of hypothyroidism are reviewed separately. (See "Disorders that cause hypothyroidism" and "Clinical manifestations of hypothyroidism" and "Treatment of hypothyroidism".)
Myxedema coma can occur as the culmination of severe, long-standing hypothyroidism or be precipitated by an acute event such as infection, myocardial infarction, cold exposure, or the administration of sedative drugs, especially opioids.
The demographics of patients who develop myxedema coma are those of hypothyroidism in general, with older women being most often affected. Myxedema coma can result from any of the usual causes of hypothyroidism, particularly chronic autoimmune thyroiditis, because of its often insidious course compared with post-surgical or -ablative hypothyroidism. (See "Disorders that cause hypothyroidism".) It can occur in patients with secondary hypothyroidism, and there are case reports of its occurrence in patients with lithium- or amiodarone-induced hypothyroidism [1-3].
- Santiago R, Rashkin MC. Lithium toxicity and myxedema coma in an elderly woman. J Emerg Med 1990; 8:63.
- Waldman SA, Park D. Myxedema coma associated with lithium therapy. Am J Med 1989; 87:355.
- Mazonson PD, Williams ML, Cantley LK, et al. Myxedema coma during long-term amiodarone therapy. Am J Med 1984; 77:751.
- Kwaku MP, Burman KD. Myxedema coma. J Intensive Care Med 2007; 22:224.
- Westphal SA. Unusual presentations of hypothyroidism. Am J Med Sci 1997; 314:333.
- Jansen HJ, Doebé SR, Louwerse ES, et al. Status epilepticus caused by a myxoedema coma. Neth J Med 2006; 64:202.
- Woods KL, Holmes GK. Myxoedema coma presenting in status epilepticus. Postgrad Med J 1977; 53:46.
- Haupt M, Kurz A. Reversibility of dementia in hypothyroidism. J Neurol 1993; 240:333.
- Iwasaki Y, Oiso Y, Yamauchi K, et al. Osmoregulation of plasma vasopressin in myxedema. J Clin Endocrinol Metab 1990; 70:534.
- Zwillich CW, Pierson DJ, Hofeldt FD, et al. Ventilatory control in myxedema and hypothyroidism. N Engl J Med 1975; 292:662.
- Lee, CH, Wira, CR. Am J Emerg Med 2009; 27:1021.
- Klein I. Thyroid hormone and the cardiovascular system. Am J Med 1990; 88:631.
- Shenoy MM, Goldman JM. Hypothyroid cardiomyopathy: echocardiographic documentation of reversibility. Am J Med Sci 1987; 294:1.
- Hylander B, Rosenqvist U. Treatment of myxoedema coma--factors associated with fatal outcome. Acta Endocrinol (Copenh) 1985; 108:65.
- Dutta P, Bhansali A, Masoodi SR, et al. Predictors of outcome in myxoedema coma: a study from a tertiary care centre. Crit Care 2008; 12:R1.
- Beynon J, Akhtar S, Kearney T. Predictors of outcome in myxoedema coma. Crit Care 2008; 12:111.
- Yamamoto T, Fukuyama J, Fujiyoshi A. Factors associated with mortality of myxedema coma: report of eight cases and literature survey. Thyroid 1999; 9:1167.
- Rodríguez I, Fluiters E, Pérez-Méndez LF, et al. Factors associated with mortality of patients with myxoedema coma: prospective study in 11 cases treated in a single institution. J Endocrinol 2004; 180:347.
- MacKerrow SD, Osborn LA, Levy H, et al. Myxedema-associated cardiogenic shock treated with intravenous triiodothyronine. Ann Intern Med 1992; 117:1014.
- HOLVEY DN, GOODNER CJ, NICOLOFF JT, DOWLING JT. TREATMENT OF MYXEDEMA COMA WITH INTRAVENOUS THYROXINE. Arch Intern Med 1964; 113:89.
- Arlot S, Debussche X, Lalau JD, et al. Myxoedema coma: response of thyroid hormones with oral and intravenous high-dose L-thyroxine treatment. Intensive Care Med 1991; 17:16.
- Wartofsky L. Myxedema coma. In: The Thyroid: A Fundamental and Clinical Text, Braverman LE, Utiger RD (Eds), Lippincott, Williams & Wilkins, Philadelphia 2000. p.843.