| Brennan et al., Rochester, MI, USA, studied body composition in 34 patients with overt hyperthyroidism (OH) and 19 with subclinical hyperthyroidism (SH), before and after treatment following a euthyroid interval of between 6–12 months. Parallel data from 23 euthyroid subjects as controls were also collected. Treatment of OH resulted in a mean weight gain of 10% (9.7% fat body mass and 6.8% lean body mass). In SH these values were respectively 5.5% (7.6% and 7.5%). (Comment: Subclinical hyperthyroidism in this study has been defined as a suppressed serum TSH with normal FT4. Assuming that T3 serum levels are also within normal range, this study suggests that subclinical hyperthyroidism is also a pathological condition, qualitatively not very dissimilar from overt hyperthyroidism, at least with regard to body composition.) Arata et al., Tokyo, Japan, measured bone loss during thyrotoxicosis and after correction of thyroid function in females of three different age groups: pre-menopausal < 35 years, pre- menopausal 35 years, and post-menopausal. In total 45 untreated patients were studied and 36 treated patients who were euthyroid for more than 3 years. The results show that bone loss is remarkable in pre-menopausal women < 35 years, absent in pre-menopausal women 35 years, and mild in post-menopausal patients. Bone mass was restored after treatment in both groups. (Comment: the totally different results in the two pre-menopausal groups is not readily understood.) Poertl et al., Essen, Germany, studied the TSH suppressive effect of hCG in 85 women in the first trimester of normal pregnancy, 30 patients with a vesicular hydatid mole and 12 patients with choriocarcinoma. They found that TSH was more frequently suppressed with increasing hCG serum values in all three groups of subjects. In normal pregnancy TSH was suppressed in 28%, in hydatid mole in 47%, and in choriocarcinoma in 67% of patients. Overt hyperthyroidism was present in 1%, 27%, and 33% respectively. However, when subjects of the 3 groups who had similar hCG levels were compared, it appeared that the frequency of hyperthyroidism was lowest in normal pregnancy and highest in choriocarcinoma. (Comment: The authors suggest that not only hCG per se, but also the source of its production is determinant in the development of hyperthyroidism. This conclusion unfortunately is not substantiated by statistical analysis because of the limited number of patients. However, if this conclusion appears to be true, then it would be interesting to analyse if these different thyroidal responses to hCG are caused by differences in biological activity of hCG in the different groups of subjects.) |
