An update for the controversies and hypotheses of regulating nonthyroidal illness syndrome in chronic kidney diseases.

Nonthyroidal illness syndrome (NTIS) is widely found in the patients with chronic kidney disease (CKD) or critical illness. However, the exact pathogenesis and reasonable treatment remain unclear. To identify suitable studies for inclusion in present review, a search for articles using PubMed search engine with combined terms: (thyroid OR hypothyroidism OR hyperthyroidism OR triiodothyronine) AND (glomerulonephritis OR chronic kidney disease OR chronic renal failure OR end stage renal disease OR hemodialysis OR peritoneal dialysis OR kidney transplantation OR renal transplantation) was performed. The bibliographies of relevant articles were also hand searched. The search was updated on November 8, 2013. Mechanisms for the alternations of thyroid hormone concentrations in NTIS are complicated. Inflammatory cytokines and oxidative stress may play pivotal roles in the pathogenesis of NTIS in patients with CKD. It was controversial whether CKD patients with NTIS should be treated with thyroid hormone replacement. N-Acetyl cysteine or sodium bicarbonate may negatively regulate the progress of micro-inflammation in CKD. Large-scale, multi-centered randomized controlled trials should be conducted to verify the NTIS hypothesis in CKD patients.