Apathetic hyperthyroidism presenting as tricuspid regurgitation.

Apathetic hyperthyroidism, as its name implies, presents itself in an insidious manner so that the diagnosis may be oliscure until a near-terminal situation. Such was the situation in two elderly women manifesting lethargy, muscular weakness, and anasarca associated with severe Mcnspid regurgitation. Both had been unresponsive to the usual medical regimen consisting of digitalis and diuretics for congestive failure until they were discovered to be thyrotoxic. A p propriate treatment and a return to a enthyroid state resulted in remarkable sobjective improvement as well as disappearance of signs of congestive failure and tricuspid regurgitation. The possible mechanisms whereby thyrotoxicosis could lead to predominantly right-sided failure are discussed.