Prevalence of thyroid disorder in patients with systemic lupus erythematosus and patients with lupus nephritis

Background Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that can affect many organs. Lupus nephritis (LN) is a major cause of morbidity and mortality in patients with SLE. The interaction between kidney and the thyroid-gland functions has been known for a long time. Thyroid hormones (TH) are necessary for growth and development of the kidney, and for the maintenance of water and electrolyte homeostasis. On the other hand, kidney is involved in the metabolism and elimination of TH. Thyroid disease appears to be more frequent in SLE patients than in the general population. Therefore, screening of thyroid dysfunction in patients with SLE, especially in those with evidence of LN, is recommended. The aim of this work is to study morphological (thyromegaly and thyroid nodules) and functional (hypothyroidism or hyperthyroidism) thyroid disorders in patients with SLE with or without renal affection, and whether LN acts as an independent risk factor of thyroid abnormalities. Patients and methods In total, 60 participants were divided into three groups: group I: 20 patients diagnosed with SLE without evidence of renal affection, group II: 20 patients diagnosed with SLE with evidence of LN, and group III: 20 healthy participants. All were subjected to full history taking, thorough physical examination, laboratory investigations (urea and creatinine), thyroid function, and serological marker serum [antithyroid peroxidase antibody (anti-TPO Ab)]. Ultrasound examination of the thyroid gland was done. Results There was a direct significant relationship between renal function tests, namely urea and creatinine and anti-TPO among cases with SLE, both without and with LN, and an inverse significant relationship between estimated glomerular filtration rate and anti-TPO among both the SLE group and the LN group. Conclusion Screening of thyroid dysfunction in patients with SLE, especially in those with evidence of LN by estimation of thyroid function tests, thyroid autoantibodies, and by ultrasonography, is recommended.