SELENIUM DEFICIENCY AND THYROID-FUNCTION IN ACUTE-RENAL-FAILURE

The lethality of acute renal failure exceeds 50% due to multiorgan dys function. In such critically ill patients a reduction of thyroid hormo ne concentrations without clinical symptoms or laboratory evidence of hypothyroidism frequently occurs. Selenium has recently been shown to play a major role in thyroid hormone metabolism. The aim of this study was to investigate the possible influence of selenium on thyroid horm one metabolism in acute renal failure. Changes in thyroid metabolism w ere related to the severity of multiorgan failure and to the clinical course. Thyroxine (T4), tri-iodothyronine (T3), free-T4, free-T3, thyr otropin (TSH), serum creatinine, and plasma selenium concentrations in 28 patients (mean age 60 +/- 13) with acute renal failure and multipl e-organ dysfunction syndrome were determined initially, and every 3 da ys after hospital admission. The plasma selenium concentration was fou nd to be reduced compared to normal controls (32 +/- 14 vs. 70-120 mu g/L). T4 (56 +/- 15 nmol/L, normal range 64-148)), T3 (1.31 +/- 0.38 n mol/L, normal range 1.42-2.46), free-T3 (3.1 +/- 1.0 pmol/L, normal ra nge 4.7-9.0), and free-T4 (10.8 +/- 4.0 pmol/L, normal range 10.3-25.8 ) values were low in 50-70% of the patients at the time of presentatio n. Plasma TSH concentrations were within the normal range (0.59 +/- 0. 79 mU/L, normal range 0.25-3.1), and no clinical symptoms of hypothyro idism were observed. T4 concentration was higher in patients who survi ved acute renal failure compared to nonsurvivors (62 +/- 22 vs. 51 +/- 16 nmol/L, p < 0.05). Plasma selenium concentration was lower in pati ents with a severe organ dysfunction syndrome (36 +/- 10 vs. 29 +/- 19 mu g/L) and correlated with the number of organ failures in these pat ients (r = -0.247, p < 0.05). T4 and free-T4 values paralleled decreas ing selenium concentrations (r = 0.35, p < 0.05). Thyroid hormone leve ls were reduced in patients with acute renal failure without an increa se in TSH. An increase in T4 concentrations became apparent during tre atment and may be related to a favorable outcome in acute renal failur e. Thyroid hormone concentrations paralleled plasma selenium levels, i ndicating a possible influence of selenium on thyroid function in acut e renal failure.