Subclinical hypothyroidism among Egyptian children with systemic lupus erythematosus

Background: Thyroid autoimmune diseases have been associated with systemic lupus erythematosus (SLE). Both hypothyroidism and hyperthyroidism are seen, but hypothyroidism is the most common abnormality. Subclinical hypothyroidism (SCH) has been reported among adult lupus patients. SCH is not without risk as it might contribute to a proatherogenic state. Objectives: This study was aimed to assess the frequency of SCH in a group of Egyptian children with SLE and its effects on the serum lipids. Methods: Forty patients with pediatric SLE who regularly follow up at our center were enrolled in this study. They were subjected to routine laboratory investigations of SLE and measurement of serum lipids (serum triglycerides, cholesterol, LDL and HDL) as well as free thyroxine (T4), thyroid stimulating hormone (TSH) and anti-thyroperoxidase antibody (anti-TPO-ab) titre. SLE activity was assessed using the systemic lupus erythematosus disease activity index (SLEDAI). Results: Six patients (15%) were found to have SCH while the remaining 34 patients (85%) had normal thyroid function. Anti-TPO-abs were positive in 4 out of the 6 (66.6 %) SLE patients with SCH and in 20 out of the 34 (58.8%) SLE patients with normal thyroid function. In SLE patients with SCH, TSH correlated positively yet insignificantly with anti-TPO-ab titre and the duration of SLE (p = 0.17, p = 0.12, respectively). There were no statistically significant correlations between the serum lipids of SLE patients with SCH and their thyroid function or anti-TPO-ab titre. Conclusion: SCH is not uncommon among children with SLE. This SCH does not seem to affect serum lipids. However, further longitudinal studies on wider scales are needed to assess the long term effects of SCH in those patients. Keywords: SLE, anti-thyroperoxidase antibodies, subclinical hypothyroidism Egypt J Pediatr Allergy Immunol 2011;9(2):87-92