Clinicopathological Characteristics And Prognosis Analysis Of 22 Pediatric Cases With ANCA-associated Glomerulonephritis

Objective:To analyze the clinicopathological characteristics of pediatric ANCA-associated glomerulonephritis(AAGN)and their relationship with prognosis,and to analyze the accuracy of ANCA renal risk score in predicting pediatric AAGN renal prognosis.Methods:Retrospectively summarize and analyze the clinical and pathological data of 22 pediatric cases with AAGN from the Children's Hospital of Chongqing Medical University from January 2013 to August2019.Collect the prognostic data.Analyze the relationship between clinicopathological data and prognosis.The ANCA renal risk score was used to assess the prognostic risk,and the renal survival of children in different risk groups was analyzed.Results:(1)The male-female ratio of 22 children with AAGN was 1:2.67.The average age of onset was(9.88±3.18)years.The peak age of onset was 6-12years.MPO-ANCA was positive in 19 cases(86.36%)and PR3-ANCA was positive in 3 cases(13.64%).(2)The 22 children had various initial manifestations.11 cases(50%)had onset with renal manifestations and 11 cases(50%)had onset with extrarenal manifestations.Those with renal manifestations were the most common with edema with or without oliguria(6 cases,27.27%),and those with extrarenal manifestations were most common with paleness(3 cases,13.64%).(3)Renal involvement:Renal presentation was most common with proteinuria(22 cases,100%).12 cases(54.55%)had eGFR<30ml/min/1.73m~2 at diagnosis.16 cases had renal pathological data.The most common glomerular lesions were cell-fibrotic crescents(13 cases,81.25%).6 cases(37.5%)had sclerosing lesions.Renal interstitial lesions are mainly manifested by infiltration of inflammatory cells(16 cases,100%).5 cases(31.25%)had the deposition of electron compacts or obvious immune complexes.(4)Extrarenal involvement:lungs involvement in 12 cases(54.55%),skin involvement in 10 cases(45.45%),nose involvement in 10 cases(45.45%),mucous membranes/eyes involvement in 2 cases(9.09%),and nervous system involvement in 2 cases(9.09%).Pulmonary hemorrhage manifested in 10 patients(83.33%)with lung involvement.1 case had no clinical symptoms of hemoptysis,but chest CT showed pulmonary hemorrhage.(5)20 cases have follow-up data.The median follow-up time was 9.85(2.93,32.38)months.To the last follow-up,5 cases(25%)had chronic kidney disease(CKD)stage 1,1 case(5%)CKD stage 2,1 case(5%)CKD stage 3,11 cases(55%)progressed to end-stage renal disease(ESRD),and2 cases(10%)died.The cumulative renal survival rates at 1 year,2 years,and 4 years of follow-up were 55.56%,49.38%,and 16.46%,respectively.Low eGFR level at diagnosis is a high-risk factor for children with AAGN progressed to ESRD.(6)The ANCA renal risk score were used in 14 cases.At 12 months,24 months,and 36 months of follow-up,the proportion of renal survival in each risk group decreased with increasing risk level.Survival analysis results showed that the cumulative renal survival rates among the low-risk group,medium-risk group,and high-risk group were significantly different(P=0.034).The pairwise comparison showed that the low-risk group had a better renal prognosis than the high-risk group(P=0.040).At 12 and 24months of follow-up,the cumulative renal survival rates in the low-,medium-,and high-risk groups was same as 100%,75%,and 25%respectively.Conclusion:Pediatric AAGN in our group were predominantly MPO-ANCA positive,and were more common among school-age girls.The onset manifestations varied.The most common renal manifestations were proteinuria and more than half cases had severely impaired renal function.In renal pathology,glomerular lesions were dominated by cell-fibrotic crescents.Renal interstitial lesions were dominated by infiltration of inflammatory cells.It was not uncommon for immune complexes to deposit in pediatric AAGN.Lungs were the most commonly involved extrarenal organs.The incidence of pulmonary hemorrhage was high,which could be manifested as occult alveolar hemorrhage without hemoptysis.For those with lung involvement,even if there is no clinical hemoptysis,it is recommended to complete chest CT screening early.The overall prognosis of pediatric AAGN in our group was poor,and 55%of them progressed to ESRD during follow-up.eGFR at diagnosis was related to renal prognosis.Children with lower eGFR at diagnosis were more likely to progress to ESRD and had a worse prognosis.The ARRS scoring system partially predict kidney outcomes in pediatric AAGN.The renal prognosis in low-risk group was better than that in high-risk group.The renal prognosis needs to be further verified by multi-center,large-sample research and long-term follow-up.