Myxedema coma 

• This is a state of hypothyroidism with altered con­sciousness or coma, sometimes seizures. There may be hypothermia.
• It is common in the elderly, and precipitated by seda-‘ tives, antidepressants, pneumonia, CHF, MI, cere­brovascular accidents.
• marked by neurological dysfunction, by respiratory depression, and by lowered body temperature, blood pressure, blood sugar, and serum sodium.
• System(s) affected: Endocrine/Metabolic
• These patients may be hypoxaemic, hypercapneic, hyponatremic, hypoglycemic.

Myxedema coma Risk Factors

• History of Graves disease
• Increasing age
• Personal or family history of autoimmune diseases, including type 1 DM, Addison disease
• Previous head or neck irradiation
• Previous postpartum thyroiditis
• Treatment with lithium, immune modulators such as IFN-, or the iodine-containing antiarrhythmic amiodarone

Myxedema coma DIAGNOSIS —

• The diagnosis of myxedema coma is initially based upon the history, physical examination, and exclusion of other causes of coma

Myxedema coma Initial Lab Tests

• •Primary hypothyroidism
  • Serum free T4 decreased
  • TSH elevated
• •Central hypothyroidism:
  • Impaired TSH response to TRH
  • Serum free T4 decreased
  • TSH low
• •Severe hypothyroidism:
  • Hyponatremia
  • Elevated CPK, LDH, AST
  • Elevated cholesterol
  • Anemia
• •Subclinical hypothyroidism:
  • TSH elevated
  • Serum free T4 normal

Myxedema coma Treatment

• Levothyroxine-single IV bolus 500 mcg loading dose then 100 mcg/day. Levothyroxine may be given by nasogastric tube as crushed tablets.
• Patient is kept warm.
• Hydrocortisone IV 50 mg 6 hrly is given. Broad spectrum antibiotics for infection. Hypertonic saline and IV glucose.