RESUMO
BACKGROUND/AIMS: The objective of the present study was to investigate the effect of hyperthyroidism on antral myoelectrical activity, gastric emptying and dyspepsia in man. METHODOLOGY: 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). RESULTS: 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. CONCLUSIONS: Dyspeptic patients with hyperthyroidism frequently display tachygastria and delayed gastric emptying. However, tachygastria has no important effect on gastric motor activity in hyperthyroidism.