Pathology of idiopathic nephrotic syndrome in children: are the adolescents different from young children?

BACKGROUND: There is no specific data on the pathological lesions underlying idiopathic nephrotic syndrome (INS) in adolescents in Pakistan. Moreover, it is not known whether the pathological lesions in adolescents differ significantly from young children with INS in our setup. Materials and methods. A retrospective analysis was carried out on all patients with INS with onset ≤ 18 years of age. They were split into two groups: patients with onset of INS ≤ 12 years (young children group) and patients with onset ≥ 13 through 18 years of age (adolescent group). Renal biopsies were evaluated by light microscopy, immunoflourescence and electron microscopy. The histopathological lesions on renal biopsies were analyzed and compared between the two groups.

RESULTS: The adolescents comprised 173 (32.1%) patients, and there were 365 young children (67.8%). The mean age of adolescents at the time of onset of INS was 15.12 ± 1.5 years and there were 113 boys (65.3%) and 60 girls (34.6%). The mean age of young children was 7.26 ± 3.24 years and there were 231 boys (63.2%) and 134 girls (36.7%). Focal segmental glomerulosclerosis was the most common histopathological lesion in adolescents (36.4%) followed by minimal change disease (MCD) (28.9%). Adolescent-onset INS had a significantly higher frequency of membranous glomerulonephritis and membranoproliferative glomerulonephritis (MPGN) (P < 0.05) and significantly lower frequency of MCD (P < 0.05) than early childhood-onset INS.

CONCLUSIONS: Our data indicate that the pathological lesions in adolescent INS are different from younger children and resemble more closely those seen in adults. Our findings are concordant with the few previously published studies on this subject.