myxoedema (miks-i-dee-mă) n.
1. a dry firm waxy swelling of the skin and subcutaneous tissues found in patients with underactive thyroid glands (see hypothyroidism).

2. the clinical syndrome due to hypothyroidism in adult life, including coarsening of the skin, intolerance to cold, weight gain, and mental dullness. m. coma a life-threatening condition due to severe hypothyroidism, often precipitated by an acute event, such as surgery, prolonged exposure to cold, infection, trauma, or sedative drugs.
—myxoedematous adj.

myxoedema Disease caused by deficient function of the thyroid gland, resulting in fatigue, constipation, dry skin, a tendency towards weight-gain and, in the later stages, mental dullness. It mostly affects middle-aged women. Treatment involves administration of the thyroid hormone thyroxine.

myxoedema Low metabolic rate as a result of hypothyroidism, commonly the result of iodine deficiency.