Role and relevance of renal biopsy in nephrotic syndrome

Renal biopsy remains an indispensable diagnostic and prognostic tool in the management of nephrotic syndrome, particularly among non-genetic, steroid-resistant infantile and congenital cases—which constitute nearly 70–90% of presentations. While genetic forms are generally unresponsive to corticosteroids or immunosuppressive agents, histopathological evaluation in non-genetic cases provides crucial therapeutic guidance and helps predict disease outcomes.

Histological assessment delineates steroid- and calcineurin inhibitor–responsive variants, thereby influencing treatment strategies and long-term prognosis. Focal segmental glomerulosclerosis (FSGS), although common, exhibits a limited response rate (~30%) to immunosuppression, and extensive fibrosis or chronic kidney disease often portends poor outcomes. Biopsy findings are equally pivotal in detecting calcineurin inhibitor toxicity, characterized by tubulointerstitial injury, enabling timely modification of therapy.

In systemic conditions such as lupus nephritis or syndromic disorders like Denys–Drash syndrome, renal biopsy plays a critical role in defining the extent of glomerular and interstitial involvement, tailoring immunosuppressive therapy, and planning vigilant follow-up due to potential malignancy risks. Moreover, corticomedullary junction biopsies are often more informative in early FSGS detection, while membranous nephropathy can be diagnosed even from a single glomerulus.

Distinct immunopathological features such as extensive IgM deposition in minimal change disease or mesangial proliferative glomerulonephritis, and dominant mesangial C1q deposits in C1q nephropathy, signal more aggressive disease patterns with frequent relapses and higher risk of chronic kidney disease progression—necessitating long-term or second-line immunosuppressive therapy.

Thus, renal biopsy not only serves as a cornerstone in differentiating disease subtypes and guiding individualized treatment but also plays a crucial role in optimizing outcomes and minimizing therapeutic toxicity in pediatric nephrotic syndrome.

To be updated shortly..