LONG-ACTING THYROID STIMULATOR IN GRAVES' DISEASE

Abstract

In a survey of 248 patients diagnosed as Graves' disease in Toronto hospitals, the frequency of long-acting thyroid stimulator (L.A.T.S.) was 37%. Patients treated for the first time had a lower incidence (30%) than those who had been treated previously, but age, sex, type of previous treatment, and ocular involvement, did not significantly affect the frequency. In 34 of 42 patients in whom 131I uptake was non-suppressible by triiodothyronine administration no L.A.T.S. was detected. Thus the incidence of L.A.T.S. in non-suppressible cases (19%) was smaller than in the series as a whole. The presence of L.A.T.S. therefore did not explain the non-suppressibility. In 41 cases of untreated Graves' disease there was no significant difference in serum-levels of thyroid-stimulating hormone (T.S.H.) in the presence or absence of L.A.T.S. T.S.H. was undetectable in 30% of those without L.A.T.S. and 18% of those with positive L.A.T.S. The lower frequency of L.A.T.S. in " non-suppressible " patients and the absence of a reciprocal relationship between L.A.T.S. and T.S.H. makes it seem unlikely that L.A.T.S. plays a causal role in Graves' disease.