Thyroid function in patients with acute renal failure

Thyroid function was evaluated in a group of 36 patients with acute renal failure (ARF) during the oliguric/anuric, polyuric and postpolyuric phase. Serum thyroxine (T4) and triiodothyronine (T3) concentrations were significantly decreased in the oliguric/anuric phase, as compared with the mean values obtained in the post-polyuric phase and with controls. In contrast to T3 and T4, the concentration of serum reverse triiodothyronine (rT3) was elevated in the oliguric/anuric phase and normal in the polyuric phase. The sephadex-T3-binding index (T3I) was significantly increased in oliguric/anuric patients and in the polyuric phase. The levels of serum thyreotropin were significantly elevated during all phases of ARF as compared with the controls. From the results obtained it is concluded that abnormal peripheral metabolism of T4 seems to be the primary cause of altered plasma concentrations of thyroid hormones in patients with ARF.