| Infants and Neonates :
- Serum T4 and TSH measurements should be evaluated at the following intervals, with subsequent dosage adjustment to normalize serum total T4 or FT4 and TSH
- 2 and 4 weeks after the initiation of Thyroxine sodium treatment ;
- Every 1 to 2 months during the first year of life;
- Every 2 to 3 months between 1 & 3 years of age;
- Every 3 to 12 months thereafter until growth is completed
Evaluation at more frequent intervals is advisable when compliance is poor or abnormal values are obtained. Patient evaluation is also advisable approximately 6 to 8 weeks after any change in thyroxine sodium dose.
Myxedema Coma
Myxedema coma occurs as an extreme manifestation of severe hypothyroidism seen in patients with long standing hypothyroidism that is untreated.
I Precipitating Events
- cold months
- pulmonary events
- cerebrovascular accidents
- congestive heart failure
- metabolic derangements
- drugs - sedatives, narcotics, antidepressants
II Cardinal Features
- hypothermia
- unconsciousness
- other signs of hypothyroidism
III Treatment
- treatment of underlying cause
- ventilatory support
- correction of electrolyte imbalance
hypothermia, hypotension
- steroid treatment - injection hydrocortisone 100mg, 8 hourly parenterally during initial
7-10 days then tapered off
- once patient is stable, consider evaluation of adrenal status
Thyroid Hormone Therapy (Thyroxine Sodium)
- Initial dose (loading dose), 100-500mcg followed by maintenance dose of 50-100mcg/ day
- Parenteral preparations if not available thyroxine tablets to be used through nasogastric tube, 500-1000 mcg initial dose followed by 50-100 mcg /day. Care to be taken if patient has ischaemic heart disease
- Due to illness, T4 given may not be converted to T3 so some advise T3 therapy
T3 Treatment : Quick Onset Of Action
- Bolus IV (Tri-iodothyronine) T3 20mcg, followed by 10mcg of T3 for first 24 hours and 10mcg 6 hourly for next 2-3 days then oral administration is started once patient is stable. 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
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