Effect of hyperthyroidism on antral myoelectrical activity, gastric emptying and dyspepsia in man

The objective of the present study was to investigate the effect of hyperthyroidism on antral myoelectrical activity, gastric emptying and dyspepsia in man.

Twenty-three patients with manifest hyperthyroidism and dyspepsia confirmed by a standardized protocol were studied by electrogastrography (EGG). The following EGG parameters were determined: dominant frequency (DF cycles per minute (cpm), DF (%) in the normal range (2-4 cpm)), bradygastria (< 2 cpm), tachygastria (4-10 cpm), dominant frequency instability coefficient (DFIC), and postprandial to fasting power ratio. Data were correlated to results obtained in 18 age- and gender-matched controls. In 10 patients, a control measurement was performed after antithyroid therapy. In addition, in 15 consecutive patients, EGG data were compared to gastric emptying of radionuclides recorded simultaneously (gamma camera).

Hyperthyroid patients revealed a significant increase in preprandial DF, and in pre- and post-prandial tachygastrias compared to controls (3.3 cpm vs 3.1 cpm; 8.8% vs 3.5%; 12.3% vs 3.5%; p < 0.05). After antithyroid therapy, postprandial tachygastrias were reduced significantly. About 50% of the patients exhibited delayed gastric emptying compared to previously evaluated normal values (t 60 nuclide retention: > 68%). However, these patients did not differ in tachygastria and the other EGG parameters from those with normal gastric emptying (p > 0.05). Both EGG and radioscintigraphy did not correlate significantly with dyspepsia.

Dyspeptic patients with hyperthyroidism frequently display tachygastria and delayed gastric emptying. However, tachygastria has no important effect on gastric motor activity in hyperthyroidism.