Clinical and histological features of rapidly progressive glomerulonephritis in children

Rapidly progressive glomerulonephritis (RPGN) associated with antineutrophil cytoplasmic antibodies (ANCA) is complicated in children due to the severity of the disease and the lack of clear consensus on treatment. The purpose of this research was to analyze the course of RPGN and its outcomes in children depending on the morphological basis after the results of nephrobiopsy. Materials and methods used: a single-center cohort retrospective study had been carried out as medical records’ analysis of patients diagnosed with RPGN aged 1 to 18 y/o who were observed at the Nephrology Department of the Scientific Research Institute of Pediatric Nephrology and Urology with the National Medical Research Center for Children’s Health (Moscow, Russia) in 2015-2024. Renal survival was assessed for different clinical and morphological options, the Renal Risk Score was assessed then. Results: 18 (7 m/11 f) were identified of Me age of diagnosis 14.1 [9.9; 15.5] y/o. ANCA was detected in all patients: pANCA in 12 (66.7%, 95% CI 40.9-86.7) and cANCA in 6 (33.3%, 95% CI 13.3-59.0) plus a single patient had a rare combination of dual positivity for anti-GBM and MPO-ANCA. Extrarenal manifestations were described in 10 (55.6%, 95% CI 30.8-78.5). Morphological subclassification of focal segmental glomerulosclerosis was detected in 5 (31.3%, 95% CI 11-58.7), extracapillary proliferation in 8 (50%, 95% CI 24.7-75.4), sclerosing in a single patient (6.3%, 95% CI 0.2-30.2) and the mixed one in 2 cases (12.5%, 95% CI 1.6-38.4). The median follow-up period was 21.6 [12.6-35.3] months, the outcome of stage 5 chronic kidney disease (CKD) was observed in 4, overall renal survival after 12 months was 94.4% (95% CI 84.4-100.0) and 86.6% (95% CI 70.6-100.0) after 36 months. An increase in the relative risk of achieving stage 5 CKD in patients with extrarenal (general) manifestations was detected as 1.67 times (95% CI 1.01-2.77) and 10.5 times (95% CI 1.46-75.42) in those receiving dialysis. Differences in the median glomerular filtration rate at onset were revealed in patients with extrarenal manifestations and isolated glomerulonephritis (p=0.004). Conclusion: when choosing treatment tactics for RPGN in children and assessing renal prognosis, it is necessary to take into consideration the results of a morphological study and the degree of damage to the renal tissue.