Subclinical non-autoimmune hypothyroidism in children with steroid resistant nephrotic syndrome

Abstract

Thyroid status has not been studied well in children with steroid resistant nephrotic syndrome (SRNS). In this cross sectional study we recruited 20 children aged 1-16 years with SRNS and similar number of controls. Serum levels of FT3, FT4 and TSH were measured in all the subjects. Overt hypothyroidism was defined as low FT4 (normal values: 0.7-2.0 ng/mL) and elevated serum TSH above reference values (0.45-4.5 mIU/L). Subclinical hypothyroidism (SH) was defined as an elevation in serum TSH with a normal serum FT4 concentration. The primary outcome measure was serum levels of FT3, FT4 and TSH in children with SRNS. Thirty per cent of the children (n = 6) with SRNS had non-autoimmune subclinical hypothyroidism (2 children each with grade I, II and III). Children with SRNS had a median TSH value [3.9 mIU/L (0.5-13)] within normal range, but levels were high as compared to controls. Out of 6 children with SH, 3 were in partial remission, 3 were in complete remission. The TSH levels normalized on thyroxine supplementation in grades II and III subclinical hypothyroidism. Subclinical non-autoimmune hypothyroidism is present in a significant proportion of children with SRNS despite partial or complete remission. Thyroid profile should be evaluated routinely in this subset of patients.