In this quick review, we will discuss salient features of two complications of thyroid disorders
- Myxedema coma, a complication of hypothyroidism
- Thyrotoxic crisis (thyroid storm), a complication of hyperthyroidism
A. Myxedema Coma
- It is a medical emergency and a rare presentation of severe hypothyroidism.
- Depressed levels of consciousness in elderly who appear myxedematous/ obese should raise suspicion for severe hypothyroidism
- Body temperature may be as low as 25 degrees Celcius
- Convulsions may occur
- CSF pressures may be high, and CSF protein levels may be raised.
- Mortality more than 50% if not treated promptly.
Treatment should begin before biochemical confirmation.
- Since Thyroxine (T4) is not available for parenteral use, an intravenous bolus of triiodothyronine (T3) is given in the dose of 20 micrograms 8 hourly till substantial clinical improvement is noted.
- In those who survive, there is a rise in temperature within 24 hours.
- Substitute with oral thyroxine after 48-72 hours (400-600 microgram loading dose followed by 1.6microgram per kilogram per day)
- Unless it is proven or documented to be a primary hypothyroidism (neck scar/ goiter), thyroid failure is assumed to be secondary hypothyroidism (pituitary or hypothalamic dysfunction)
- Intravenous hydrocortisone 100mg must be given 8 hourly as these patients have a concomitant adrenal suppression. It may be tapered slowly thereafter.
- Slow rewarming, cautious use of intravenous fluids, broad-spectrum antibiotics, and high flow oxygen should also be administered alongside.
B. Thyrotoxic crisis
- Thyrotoxic crisis also known as thyroid storm is a life-threatening condition and a severe manifestation of thyrotoxicosis.
- It may be precipitated by infections, subtotal thyroidectomy or radiation therapy
- Clinical manifestation can be remembered using the mnemonic- ‘FACT-AF’
A– Atrial fibrillation
F– Failure/ Heart failure in elderly
Timely management is the key. Clinical suspicion should help initiate treatment. Biochemical confirmation should be sent
- Resuscitate- If patient presents in a comatose condition.
- Careful cardiac monitoring throughout the management
- Rehydration with intravenous fluids
- Broad spectrum antibiotics
- Propanolol- (80 mg 6 hourly PO or 1-5mg 6 hourly i.v)
- Sodium ipodate (500mg per day)
- Restores T3 levels within 48-72 hours
- Better than Potassium Iodide or Lugol’s iodine
- Decreases T3 release
- Decreases T4 to T3 conversion
- Alternatively, dexamethasone 2 mg 6 hourly and amiodarone may be given.
- Carbimazole 40-60 mg per day
- Inhibits new thyroid hormone synthesis
- No parenteral preparation available
- In unconscious patient, per rectal route is also effective.