Creatine kinase as a supportive test in thyroid disorders

Abstract

Background: Musculoskeletal disorders are common in patients with hypothyroidism, and are also observed in thyrotoxicosis. Creatine kinase (CK) is present in the muscles and is involved in energy metabolism. This study aimed to estimate the serum CK levels in patients with hypothyroidism, hyperthyroidism, and healthy individuals. Moreover, the correlation of CK levels with markers of thyroid function is assessed. Methods: A total of 120 patients with hypothyroid and 120 with hyperthyroid were compared with 120 healthy individuals aged 20-60 years. The thyroid status was assessed by determining the serum thyroid-stimulating hormone (TSH) and free thyroxine (fT4) using chemiluminescent immunoassay. Serum CK was measured the by kinetic method. Statistical analysis was performed by analysis of variance and Pearson’s correlation to investigate the correlations between CK and thyroid hormones. Results: A significant increase (P<0.0001) and a significant decrease (P<0.0001) in serum CK were observed in hypothyroid patients (253.98±129.04 IU/L) and in hyperthyroid patients (34.68±13.15 IU/L), respectively, compared to the control group (72.9±29.01 IU/L). A negative correlation was found between fT4 and CK (r: -0.4253, P<0.0005). Conclusion: It could be concluded that CK activity in serum may be a useful additional test in thyroid disorders.

Keywords

• creatine kinase
• hypothyroidism
• hyperthyroidism