Apathetic thyrotoxicosis: A distinctive clinical and laboratory entity.

Abstract

Nine patients with apathetic thyrotoxicosis were studied over a 1-year period and compared with 29 typical hyperthyroid subjects. These apathetic patients were significantly older and had a longer duration of symptoms and greater weight loss. The study group had a rather typical apathetic, placid, or depressed appearance often thought to represent "old age depression." Cardiovascular symptoms, atrial fibrillation, and congestive heart failure were common. They typically had evidence of a moderately severe proximal myopathy. Thyromegaly, although usually present, was not prominent and was usually multinodular. There was a striking absence of eye signs generally associated with thyrotoxicosis, and blepharoptosis was frequently observed. Although the protein-bound iodine and 131I thyroidal uptake were not markedly elevated, the diagnosis was easily established by utilizing the usual tests of thyroid function and integrating the results with the rather typical clinical features.