In this quick review, we will discuss salient features of two complications of thyroid disorders

1. Myxedema coma, a complication of hypothyroidism
2. Thyrotoxic crisis (thyroid storm), a complication of hyperthyroidism

 

A.   Myxedema Coma

 

1. It is a medical emergency and a rare presentation of severe hypothyroidism.
2. 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

1. Convulsions may occur
2. CSF pressures may be high, and CSF protein levels may be raised.
3. Mortality more than 50% if not treated promptly.

 

Management

Treatment should begin before biochemical confirmation.

1. 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.
2. 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)

1. 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)
2. Intravenous hydrocortisone 100mg must be given 8 hourly as these patients have a concomitant adrenal suppression. It may be tapered slowly thereafter.
3. Slow rewarming, cautious use of intravenous fluids, broad-spectrum antibiotics, and high flow oxygen should also be administered alongside.

 

B.   Thyrotoxic crisis

 

1. Thyrotoxic crisis also known as thyroid storm is a life-threatening condition and a severe manifestation of thyrotoxicosis.
2. It may be precipitated by infections, subtotal thyroidectomy or radiation therapy

• Clinical manifestation can be remembered using the mnemonic- ‘FACT-AF’

F– Fever

A– Agitation

C– Confusion

T– Tachycardia

A– Atrial fibrillation

F– Failure/ Heart failure in elderly

Management

Timely management is the key. Clinical suspicion should help initiate treatment. Biochemical confirmation should be sent

1. Resuscitate- If patient presents in a comatose condition.
2. Careful cardiac monitoring throughout the management

• Rehydration with intravenous fluids

1. Broad spectrum antibiotics
2. Propanolol- (80 mg 6 hourly PO or 1-5mg 6 hourly i.v)
3. 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.