Oxidative stress in patients with thyroidectomy and thyroparathyroidectomy under replacement therapy.

Several studies have demonstrated an imbalance between free radicals and the antioxidative system in individuals with thyroid dysfunction. However, oxidative stress has not been evaluated in patients with thyroidectomy and thyroparathyroidectomy, who are under replacement therapy. The objective of this study was to evaluate the oxidative stress using malondialdehyde, nitric oxide, and catalase levels in patients with thyroidectomy and thyroparathyroidectomy. Nineteen patients with thyroidectomy, 20 patients with thyroparathyroidectomy, and 20 controls with no history of thyroid or parathyroid disease or surgery were included in the study. Serum malondialdehyde, nitric oxide, and catalase levels were examined. Levels of nitric oxide and malondialdehyde were elevated, and catalase levels decreased in patients with thyroidectomy and thyroparathyroidectomy compared with controls (p value for all the parameters: p<0.001). Free tetraiodothyronine was a potential predictor of malondialdehyde in the patient groups (p: 0.002). Catalase was negatively correlated with nitric oxide (p<0.01) and malondialdehyde (p<0.01). The results of the current study demonstrated that oxidative stress increased in patients with thyroidectomy and thyroparathyroidectomy despite the application of replacement therapies.