Myxedema coma occurs as an extreme manifestation of severe hypothyroidism, seen in patients with long standing hypothyroidism that is untreated.
Precipitating events
Cold months
Pulmonary events
Cerebrovascular accidents
Congestive heart failure
Metabolic derangements
Drugs- sedatives, narcotics, antidepressants
Cardinal Features
Hypothermia
Unconsciousness
Other signs of hypothyroidism
Treatment
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Treatment of underlying cause |
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Ventillatory support |
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Correction of electrolyte imbalance, hypothermia, hypotension. |
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Steroid treatment -Inj Hydrocortisone 100mg, 8 hourly parenterally during initial 7 -10 days then tapered off . |
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Once patient is stable, consider evaluation of adrenal status. |
Thyroid Hormone Therapy (Thyroxine Sodium)
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Initial dose (loading dose ), 100-500mcg followed by maintenance dose of 50-100mcg/day. |
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Parenteral preparations if not available, thyroxin tablets to be used through nasogastric tube, 500- 1000 mcg initial dose followed by 50-100 mcg /day. |
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Care to be taken if patient has ischemic heart disease. |
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Due to illness, T4 given may not be converted to T3 so some advise T3 therapy |
T3 treatment: Quick onset of action
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Bolus IV (Triiodothyronine) T3 20mcg, followed by 10 mcg of T3 for first 24 hours and 10 mcg 6 hourly for next 2-3 days, then oral administration is started once patient is stable. |
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However intravenous T3 therapy is marked by large and unpredictable fluctuations in serum T3 levels and is dangerous to the cardiac status. |
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| Some advocate combination of T3 and T4 treatment |