Endocrine and Metabolic 3:
Myxedma Coma (Severe Hypothyroidism) Portal
Myxedema coma is a rare manifestation of severe hypothyroidism occurring
especially in untreated hypothyroid geriatric patients who develop a
serious illness such as CHF, CVA, or infection.
Clinical Presentation (* indicates classic)
- * Decreased LOC ranging from lethargy to coma
- * Hypoventilation with respiratory insufficiency
- * Hypothermia (sometimes severe)
- Hypotension
- Bradycardia
- Typical hypothyroid features of dry skin, slow deep brief breaths, slow deep tendon reflexes, coarse hair, macroglossia
Laboratory Findings
- * Severe hyponatremia
- Elevated CPK and LDH
- Anemia
- Acidosis
- Elevated TSH and decreased free thyroid index
Treatments
- Supportive general care is the most
important part of treatment.
- Pay special attention to the ABCs (ie, maintain adequate airway, ventilation, breathing, and circulation).
- Treat the underlying illness (ie, CHF, CVA, pneumonia, sepsis).
- Warm the patient.
- Treat the dilutional hyponatremia.
- Specific drug therapy for myxedema
coma:
- First, administer IV steroids (as in Addisonian crisis or adrenal crisis) since many patients with myxedema coma have decreased adrenal reserve.
- Start IV steroid hormone therapy to ensure systemic availability of the hormone.
- Give initial loading dose of L-T4 hormone 200 to 300 µg IV followed 24 hours later with a second dose (100 µg) IV.
- Concomitantly, give L-T3 hormone 10 µg IV every 8 hours until the patient is stable and conscious.