Liver volume, portal vein flow, and clearance of indocyanine green and antipyrine in hyperthyroidism before and after antithyroid treatment

Background: The aim of the study was to examine liver volume, portal vein f low, and indocyanine green (ICG) and antipyrine clearance in hyperthyroidis m before and after antithyroid drug treatment. Methods: Liver volume and bl ood flow in the portal vein were investigated in nine fasting patients with hyperthyroidism by means of computed tomography scan and Doppler ultrasoun d, respectively. ICG clearance was estimated by bolus injection of ICG (0.5 mg/kg body weight) and antipyrine clearance with a one-sample technique. A ll patients were investigated before and after 3 months of antithyroid trea tment, when euthyroidism had been achieved. The Wilcoxon matched-pairs test was used for statistical analysis. Results: The median liver volume increa sed by 238 (155-289) ml (median, 95% confidence interval), corresponding to 19%, and the weight by 5.0 (0.0-8.0) kg (8%), and the antipyrine clearance decreased by 8 (3.1-34.4) ml/min (16%). These changes were all significant (P < 0.05). The relation between liver volume and body weight increased fr om 19.9 (16.5-23.7) ml/kg to 21.4 (17.1-21.9) ml/kg (P = 0.11). The liver b lood how as estimated by ICG clearance and Doppler ultrasound was not alter ed significantly after the treatment period (P = 0.07 and 0.77, respectivel y). Conclusions: The liver volume increased by 19% in nine hyperthyroid pat ients during treatment with antithyroids. Antipyrine clearance was reduced by 16%, whereas liver blood how, as estimated by ICG clearance and Doppler ultrasound examination of portal-vein flow, was not significantly altered. A differential regulation of liver volume and oxidative metabolic capacity in hyperthyroidism was seen.