Thyroid hormones and thyroid-stimulating hormone in Egyptian patients with systemic lupus erythematosus: correlation between secondary hypothyroidism and neuropsychiatric systemic lupus erythematosus syndromes

Abstract

The purpose of this study was to determine the serum levels of thyroid hormones and thyroid-stimulating hormone (TSH), in addition to antithyroglobulin and antimicrosomal antibodies and to investigate the correlation between these hormones and various disease manifestations among Egyptian patients with systemic lupus erythematosus (SLE). A group of 45 patients with SLE (43 women and 2 men with a mean age of 27.57 ± 9.89 years) underment assessment of their thyroid hormones. Antithyroglobulin and antimicrosomal antibodies were assessed in 27 patients. Various disease manifestations were evaluated. A group of 20 normal female volunteers were involved as controls. The mean serum free triiodothyronine (FT3) levels in all patients were significantly lower than in controls (1.89 ± 1.14 vs. 3.15 ± 0.93 pg/ml; P < 0.05). Patients with a history of intravenous pulsed cyclophosphamide therapy showed significantly decreased levels of FT3 compared to those in other patients (1.17 ± 0.5 vs. 2.05 ± 0.95 pg/ml; P = 0.04). The mean serum free thyroxine (FT4) levels in all patients were significantly less than in the control group (1.24 ± 1.22 vs. 1.4 ± 0.3 mg/dl; P < 0.001). Of the 45 patients, 2 (4.4%) were considered to have primary hypothyroidism. Five of six patients (83.3%) with decreased FT4 levels developed fibromyalgia compared to 7 of 39 (17.9%) patients with normal T4 (P = 0.003). The mean serum TSH levels in all patients were significantly higher than in the controls (4.82 ± 22.2 vs. 2.65 ± 1.18 μIU/ml; P < 0.001). Six patients with decreased TSH levels were considered to have secondary hypothyroidism (13.3%); one of them showed decreased T3 and T4, two had decreased T4 only, and the other three were euthyroid. Comparing patients with and without secondary hypothyroidism, showed acute confusion in four (66.7%) in the former group versus four (10.3%) in the latter group (P = 0.006), anxiety in four (66.7%) in the former group versus six (15.4%) in the latter group (P = 0.016), and cognitive disorders in five (83.3%) in the former group versus nine (23.1%) in the latter group (P = 0.008).This study demonstrated evidence of secondary as well as primary hypothyroidism in SLE patients and revealed a close association between thyroid hormones or TSH and some organ involvement in SLE.