T4 in myxedema coma

 Q: In myxedema coma, a loading dose of T4 should be avoided to decrease the risk of arrhythmias?

A) True

B) False

Answer: B

There are two strategies to administer intravenous T4 in myxedema coma 

• 100 mcg daily without a loading dose 
• 500 mcg loading dose followed by 100 mcg daily 

Evidence (though weak) tends to favor the strategy with loading dose to show the lower mortality. The risk of arrhythmias with loading dose is preferred to be accepted in view of very high mortality (up to 50%) of myxedema coma.

#endocrinology

References:

1. Jonklaas J, Bianco AC, Bauer AJ, et al. Guidelines for the treatment of hypothyroidism: prepared by the american thyroid association task force on thyroid hormone replacement. Thyroid 2014; 24:1670.

2. Rodríguez I, Fluiters E, Pérez-Méndez LF, et al. Factors associated with mortality of patients with myxoedema coma: prospective study in 11 cases treated in a single institution. J Endocrinol 2004; 180:347.