Abstract: Background: Kidney injury is one of the risk factors for poor prognosis of HenochSchnlein purpura nephritis(HSPN) , however, there were few researches about the clinical and pathological features of HSPN with acute kidney injury (AKI). Objective: To investigate the pathological features and risk factors for HSPN complicated with AKI in children. Design: Casecontrol study. Methods: Consecutive cases of HSPN diagnosed by kidney biopsy from January 2016 to December 2020 in Guiyang Maternity and Child Care Hospital were included. According to whether AKI was combined or not, the children were divided into the AKI group and the nonAKI group. Demographic data, clinical symptoms, clinical classification, laboratory examination on the day of admission, 24hour blood pressure, pathological grade of kidney biopsy (including classification of ISKDC pathology and Oxford classification) and treatment were extracted from the medical records. Main outcome measures: The risk factors for HSPN with AKI. Results: Among 181 cases diagnosed with HSPN, there were 18 cases(10.0%) complicated with AKI, and 163 cases without AKI. The differences in sex, age of onset, albumin levels and PLT counts between the two groups of children were not statistically significant. The incidence of gross hematuria, the duration of gross hematuria, the level of 24hour urine protein, the level of 24hour creatinine and ambulatory blood pressure in the AKI group were higher than those of children in the nonAKI group, and the differences were statistically significant. The clinical classification difference was statistically significant between the two groups(χ2=8.942,P=0.003).The main clinical classification of AKI group was acute nephritis and nephrotic syndrome, while for nonAKI group it was hematuria and proteinuria type and nephrotic syndrome type. ISKDC classification difference was statistically significant between the two groups(χ2=4.586,P=0.032) that the proportion of type Ⅲ and above was higher in AKI group. According to the Oxford typing score,the proportion of tubular/interstital lesions (T1/T2) and crescent (C1/C2) in AKI group was higher than those in the nonAKI group, and the differences were statistically significant(χ2 was 9.625 and 7.961,P Value was 0.002 and 0.005). Logistic regression showed that acute nephritis in clinical classification, and the tubular stromal lesions in the Oxford classification were two risk factors for AKI in children with HSPN. After treatment, 17 cases in AKI group achieved normal renal function, and one case developed chronic kidney disease. Conclusion: HSPN with AKI is featured by severe clinical and pathologic classifications. Acute nephritis by clinical classification and tubulointerstitial lesions by Oxford typing score were the two risk factors for AKI in children with HSPN.

Key words: Henoch schonlein purpura nephritis, Acute kidney injury, Clinical manifestation, Renal pathology, Children