Gastric emptying in hyperthyroidism

We undertook a prospective study to survey gastric emptying of a solid meal in patients with hyperthyroidism until euthyroidism was reached after pharmacological treatment with thiamazole.

Eleven women (aged 33.2 +/- 3.2 SE yr) with recently diagnosed hyperthyroidism participated in the study. Thyroid function parameters and gastric emptying were examined on three occasions, before treatment, during the third week of treatment, and after euthyroidism was restored. The control group was composed of 12 age-matched healthy women (aged 34.5 +/- 2.3 yr). Gastric emptying of a 390-kcal 99mTc-labeled solid meal was continuously recorded under a gamma camera over 90 min. A power-exponential model was used for analysis of the gastric emptying course. Three gastric emptying parameters were computed: t1/2, the gastric half-emptying time, S, the curve shape parameter, and K, the slope of the curve.

Pretreatment solid phase gastric emptying of the patients was not statistically significantly different from that of the healthy control subjects: t1/2, 82.8 +/- 4.9 vs 93.5 +/- 6.0 min; S, 0.996 +/- 0.103 vs 1.032 +/- 0.064; and K, 8.42 +/- 0.47 vs 7.64 +/- 0.39 min(-1) x 10(-3). Gastric emptying during the third week of treatment did not change in comparison with pretreatment gastric emptying: t1/2, 84.3 +/- 8.2 min; S, 1.014 +/- 0.123; and K, 8.92 +/- 1.12 min(-1) x 10(-3). On the other hand, a slight increase in rate of gastric emptying was observed after the restoration of euthyroidism (t1/2, 74.6 +/- 5.8 min, and K, 9.65 +/- 0.76 min(-1) x 10(-3), p < 0.05 vs healthy control subjects for both parameters), but no significant change was observed in the shape parameter (S, 0.980 +/- 0.066).

In women with hyperthyroidism, gastric emptying of solids does not differ significantly from that observed in age-matched healthy control subjects and remains unaffected during pharmacological treatment. After restoration of euthyroidism, a slight but statistically significant increase in the rate of gastric emptying occurs in patients as compared with healthy control subjects.