What is the Origin of Myxedema Coma?

The term originated from the observation of myxedema, the non-pitting edema caused by mucopolysaccharide deposition in the skin, in patients with advanced hypothyroidism. The "coma" designation was later added to describe the severe central nervous system depression seen in the most critical cases. The condition is typically precipitated by a stressor, such as infection, cold exposure, or certain medications, pushing the already compromised hypothyroid system past its adaptive capacity.

What is the Mechanism of Myxedema Coma?

The underlying mechanism is a catastrophic failure of cellular metabolism due to the near-total deficiency of active thyroid hormone, triiodothyronine (T3). Thyroid hormones are essential for maintaining basal metabolic rate and thermogenesis across all tissues. Their severe absence leads to a dramatic decrease in oxygen consumption, resulting in multi-organ system slowing. This metabolic deceleration culminates in decreased cardiac output, respiratory depression, and cerebral hypoperfusion, manifesting as the characteristic depressed mental state and hypothermia.

Myxedema Coma ∞ Area

Myxedema Coma

Meaning

Myxedema Coma is a rare but life-threatening endocrine emergency representing the extreme, decompensated manifestation of long-standing, severe hypothyroidism. Despite its name, patients are often stuporous or delirious rather than truly comatose, but they exhibit profound hypometabolism. The cardinal clinical features include altered mental status, significant hypothermia, and bradycardia. This condition requires immediate, aggressive treatment with intravenous thyroid hormone and often glucocorticoids due to the high associated mortality rate.