Thyroid Acropachy

Published Online:https://doi.org/10.1148/83.6.1039

Thyroid acropachy is a curious and unusual complication of thyroid disease with characteristic radiologic findings. The term acropachy, from the Greek word for thickening of the extremities, was first employed by Högler (10) in 1920 in discussing the secondary osteoarthropathies. Periosteal proliferation secondary to thyroid disease was described by Thomas (19) in 1933 and termed thyroid acropachy. Since this first report in the English language literature, less than 30 examples have been recorded (1–9, 12–17, 19, 21).

The typical clinical picture of thyroid acropachy consists in insidious onset of swelling of the extremities associated with clubbing, pretibial myxedema, and exophthalmos occurring within a few weeks to many years after treatment of the original hyperthyroidism. The disorder affects the sexes with approximately equal frequency, and patients have ranged in age from the third to the eighth decades. This is of interest in view of the higher incidence of Graves' disease in females. About half the patients are euthyroid at the onset, and the others display varying degrees of hypothyroidism. Recurrent hyperthyroidism seems to be unusual. With rare exceptions, clubbing of the fingers and toes and pretibial myxedema are associated findings. Exophthalmos has been invariably present and often seemed to worsen at the onset of acropachy.

The etiology of the condition is unknown, although there has been speculation that TSH (15) or another as yet unidentified pituitary hormone is responsible for both acropachy and progressive exophthalmos. Therapy consisting of steroids with thyroid extract, triiodothyronine, local injections of hyaluronidase, and external radiation has been directed at the exophthalmos and pretibial myxedema. The various forms of treatment have had no apparent effect on the bone lesions.

The major importance of this syndrome, which seldom causes significant symptoms, lies in accurate recognition. The unique bone changes have received little attention in the radiologic literature, but, when sought, characteristic radiologic findings have been observed in over 90 per cent of the patients with this clinical diagnosis. These findings are well illustrated in the following cases.

Case Reports

Case 1: E. K., a 48-year-old white woman, was admitted to the hospital for evaluation of swelling of the hands and feet. History revealed hyperthyroidism six years previously which had been treated with I131. About three years later, the patient noted the gradual onset of painless swelling of hands and feet, pretibial edema, and clubbing.

Physical findings included exophthalmos, clubbing of the fingers and toes, pretibial myxedema, and nontender swelling of the proximal phalanges of the hands. By clinical and laboratory examination the patient was considered euthyroid.

Radiographs of the chest, forearms, lower legs, and skull were normal. The hands (Fig. 1) showed findings typical of thyroid acropachy.

Article History

Accepted: July 1964
Published in print: Dec 1964