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.