THYROTOXICOSIS FACTITIA (ALIMENTARY THYROTOXICOSIS): ITS DIFFERENTIATION FROM SPONTANEOUS THYROTOXICOSIS WITH THE AID OF RADIOACTIVE IODINE

Abstract

THE clinical picture of self-induced hyperthyroidism may be indistinguishable from that of spontaneous thyrotoxicosis but the history usually makes the differential diagnosis possible. However, some investigators have pointed out clinical symptoms by which they feel one should be able to differentiate between the two conditions. Falta (1) stated that eye signs never were present in simple hyperfunction of the thyroid. Several later investigators have been of the same opinion. Nevertheless patients with alimentary hyperthyroidism may present slight eye signs of the type seen in spontaneous thyrotoxicosis, particularly if they have previously had true Graves' disease. On the other hand, patients with endogenous thyrotoxicosis may show minimal or no eye signs. The eye signs are, therefore, not dependable in the differential diagnosis. Enlargement of the thyroid gland is usually observed in endogenous thyrotoxicosis, but occasionally palpation of the thyroid reveals no enlargement. On the other hand, patients with induced hyperthyroidism, in whom one would expect a gland of normal size, may have an enlargement due to a nontoxic goiter. Therefore one cannot make the differential diagnosis by the physical examination. In most cases of alimentary thyrotoxicosis, however, the diagnosis can be made from the history of an excessive intake of thyroid, usually in an effort to reduce weight. With cessation of the thyroid medication the symptoms will subside in a few weeks and the diagnosis can be confirmed.