Segmental necrotizing glomerulonephritis: diagnostic, prognostic, and therapeutic significance

Renal biopsies from 50 patients with segmental necrotizing glomerulonephritis (SNGN) were divided into three groups on the basis of initial clinical information: (group A) Wegener's granulomatosis (WG)--14 patients; (group B) SNGN without renal vasculitis (RV)--21 patients; and (group C) SNGN with RV--15 patients. Renal biopsy findings did not distinguish the SNGN in WG from non-WG patients. However, focal endocapillary proliferation was more common in non-WG groups B (48%) and C (33%) than in WG (7%). In addition, GBM deposits of both IgG and C3 were present in 35% of biopsies in group B and 33% in group C in comparison to only 7% in WG. Glomerular fibrin deposition was common in all groups (54% group A, 70% group B, and 100% group C), suggesting that coagulation plays a role in the development of SNGN. Histologic parameters of severity and chronicity of the SNGN were inconsistent predictors of outcome, although an increased percentage of crescents in the non-WG groups correlated with a poorer prognosis. Chronic renal failure developed in 46% of group A patients, 65% group B, and 73% group C. After clinical follow-up, 15 patients had WG, 15 patients had documented or suspected systemic vasculitis (SV), and idiopathic SNGN was present in 20 patients. Sixty-six percent of patients with SV had RV, and 62% of biopsies with RV were from patients with SV. Chronic renal failure developed in 78% of patients with idiopathic SNGN and 57% patients with SV. These findings confirm that SNGN carries a poor prognosis, independent of its association with WG or SV. Fourteen of the 15 WG patients were treated with alkylating agents, and the development of chronic renal failure appeared to be related to delays in diagnosis and therapy. In the non-WG groups, presentation in acute renal failure with high serum creatinine and long duration of symptoms was predictive of development of chronic renal failure. Therapy in the non-WG patients consisted of alkylating agents (seven patients), steroids (20 patients), and dialysis only (seven patients). The seven non-WG patients treated with alkylating agents had clinical responses similar to WG patients, and cyclophosphamide therapy appeared to be most beneficial to patient outcome. Results of this retrospective study stress the importance of early diagnosis and, although based on small numbers of patients, suggest that aggressive chemotherapy should be recommended for SNGN, independent of its association with biopsy-proven WG or documented SV.