Myxedema coma occurs as an extreme manifestation of severe hypothyroidism, seen in patients with long standing hypothyroidism that is untreated.
Precipitating events
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Cold months
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Pulmonary events
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Cerebrovascular accidents
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Congestive heart failure
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Metabolic derangements
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Drugs- sedatives, narcotics, antidepressants
Cardinal Features
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Hypothermia
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Unconsciousness
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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 parennterally 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, thyroxine 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. |
Some advocate combination of T3 and T4 treatment