Clinicopathological Features And Prognosis Of Adult Patients With Acute Post-infectious Glomerulonephritis

Acute post-infectious glomerulonephritis (APIGN) is a primary glomerulonephritis which is common in children. It could be caused by several pathogens and the most important one is acute post-streptococcal glomerulonephritis (APSGN) which is caused by group Aβhaemolytic Streptococcus. Though the incidence of APIGN is low, it has been declining in children and becoming higher in adults in recent years. Previous studies showed that the prognosis for children with APIGN was excellent since most patients could achieve complete remission. However, it was frequently poor in adults. The aim of this study is to investigate the clinicopathological features and prognosis of adult patients with acute post-infectious glomerulonephritis. Part 1. Clinicopathological features of adult patients with acute post-streptococcal glomerulonephritisObjective:To investigate clinical and pathological differences between adults and children with acute post-streptococcal glomerulonephritis (APSGN).Methods:A retrospective case series of 112 patients with APSGN was undertaken. They were divided into two groups according to age:adults aged≥18 years and children aged≤14 years. The clinical and pathological features were summarized and differences between adult and child APSGN were investigated.Results:The median age of these 52 adults and 60 children were 31.5 and 13 years, respectively. The incidence of APSGN, especially in adults, has decreased in the past three decades. The most common inducement of both groups was upper respiratory tract infection. Adults had a lower incidence of macroscopic hematuria than children (32.7% vs 58.3%, P=0.007). The incidences of edema, hypertension, renal insufficiency and nephrotic syndrome did not differ significantly between two groups. Laboratory tests showed that the incidences of hematuria and massive hematuria in adults were lower than in children (11.5% vs 41.7%, P< 0.001;11.5% vs 41.7%, P< 0.001). There were no differences on proteinuria and serum creatinine between two groups. On light microscopy, all patients presented with endocapillary proliferative glomerulonephritis, but adults had more global glomerulosclerosis (26.9% vs 8.3%, P=0.009), tubular basement membrane thickening (26.9%vs 5.0%, P=0.001), tubular atrophy (17.3%vs 5.0%, P=0.036) and interstitial fibrosis (30.8% vs 11.7%, P=0.013), and less glomerular infiltrating neutrophils and monocytes (30.8%vs 55.0%, P=0.010), subepithelial deposition (44.2% vs 66.7%,P=0.017), tubular brush border dropping (21.2% vs 40.0%, P=0.032) and cellular casts (44.2% vs 63.3%, P=0.043). Immunofluorescence microscopy showed that classical staining was seen less in adults. Adults had more IgA (38.0% vs 20.7%, P=0.047) and IgM (60.0% vs 34.5%, P=0.008) staining.Conclusion:Adults with APSGN had similar clinical features as children except that adults had less significant hematuria. On pathology, adults had more outstanding chronic changes by light microscopy and more untypical staining by immunofluorescence.Part 2. Long-term prognosis for adult patients with acute post-infectious glomerulonephritisObjective:To investigate the long-term renal outcome and prognostic factors for adult patients with acute post-infectious glomerulonephritis.Methods:A total of 62 adult patients, who diagnosed as acute post-infectious glomerulonephritis by renal biopsy, were enrolled in this study. They were divided into two groups:streptococcal group and non-streptococcal group. The clinical and pathological features were summarized. For the purpose of outcome analysis,47 patients with a follow-up of≥12 months were included. The univariate and multivariate analyses were performed for prognostic factors.Results:There were 43 patients in streptococcal group and 19 patients in non-streptococcal group. Two patients both in two groups had underlying disease. Gender and age were not different between two groups. Proteinuria (4.0±4.6g/24h vs 1.82±2.14g/24h, P=0.058) and hematuria (47.4%vs 18.6%, P=0.005) were both more severe in non-streptococcal group. On the pathological examinations, all patients manifested with endocapillary proliferative glomerulonephritis.There were no significant differences on light microscopy between two groups, but the incidences of IgG(57.9%vs 30.2%, P=0.039) and C4(31.6% vs 2.3%, P=0.002) staining on immunofluorescence were both higher in non-streptococcal group, while"hump"on electron microscopy was more seen in streptococcal group (82.4%vs 43.8%, P=0.014). Among the 47 patients with≥12 months of follow-up, the total complete remission rate was 89.4%and the incidences of chronic renal failure and ESRD were 4.3%and 2.1%, respectively. The univariate analysis showed that the prognostic factors were age (P=0.048), underlying disease (P=0.051), tubular damage (P=0.003) and C1q staining (P=0.011), respectively. On multivariate analysis, underlying disease (OR=23.9,95% CI:1.5～369.0, P=0.023) and proteinuria (OR=1.4, 95% CI:1.1～1.9, P=0.018) were significant and independent inverse correlate of complete remission.Conclusion:The long-term prognosis of adult acute post-infectious glomerulonephritis is optimistic. Underlying disease and proteinuria are important prognostic factors.