Apathetic thyrotoxicosis.

Apathetic thyrotoxicosis is an atypical though not rare manifestation of hyperthyroidism. The cardinal features are apathy and depression, as opposed to hyperkinesis and mental alertness in the usual thyrotoxic patient, and are unassociated with the usual signs and symptoms of hyperthyroidism, making the diagnosis difficult. We report three cases of apathetic thyrotoxicosis seen during one year.