Myxedema

Severe hypothyroidism characterized by generalized nonpitting, mucopolysaccharide-rich dermal and subcutaneous edema, classically involving the face and extremities, accompanied by profound slowing of metabolic processes and, in advanced cases, progression to myxedema coma.

Causes

• Primary hypothyroidism

  • Autoimmune Hashimoto's thyroiditis

  • Thyroidectomy

  • Radioiodine therapy

  • External neck radiotherapy

  • Infiltrative thyroid disease

  • Iodine deficiency

  • Congenital hypothyroidism

• Medications impairing thyroid hormone production

  • Lithium

  • Amiodarone

  • Interferon-α

  • Tyrosine kinase inhibitors

• Central causes

  • Pituitary failure

  • Hypothalamic failure

  • Pituitary tumors

  • Pituitary surgery or radiotherapy

• Triggers of myxedema coma in patients with hypothyroidism

  • Infections

  • Exposure to cold

  • Sedatives

  • Narcotics (opioids)

  • General anesthesia

  • Trauma

  • Surgery

  • Myocardial infarction

  • Stroke

  • Gastrointestinal bleeding

  • Discontinuation of thyroid hormone replacement