Objective:To provide clinical experience for the diagnosis and treatment of spontaneous renal hemorrhage through retrospective analysis of clinical features, imaging manifestations, underlying causes, treatment , and prognosis of spontaneous renal hemorrhage. Methods:By searching hospital information system, medical records scanning system, department of the interventional vascular surgery registry system, and picture archiving and communication systems, the patients with spontaneous renal hemorrhage admitted to Peking University First Hospital between January 1, 2000 to April 10, 2020 were enrolled. The clinical manifestations, investigations, imaging features, treatment, and prognosis of patients were retrospectively reviewed. The diagnostic efficiency and the accuracy of etiological diagnosis of renal hemorrhage by imaging examinations such as ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and angiography were compared and evaluated.Results:A total of 50 patients with 51 events of spontaneous renal hemorrhage were enrolled in the study. Laboratory tests showed hemoglobin was (103.3±29.4) g/L. The most common clinical features were flank or abdominal pain (48 cases, 96.0%), fever (17 cases, 34.0%), nausea (10 cases, 20.0%), vomiting (9 cases, 18.0%), and gross hematuria (4 cases, 8.0%). Nine patients (18.0%) experienced hypovolemic shock (systolic pressure<90 mmHg). With an initial assessment of the imaging method, the diagnostic accuracy of bleeding was 98.0%(49/50), yet the accuracy of underlying causes was 56.0%(28/50). The diagnostic accuracy of bleeding was 100.0%(25/25) by non-contrast abdominopelvic CT. The most common cause of spontaneous renal hemorrhage syndrome was renal tumors (27 cases, 54.0%), among which angiomyolipoma occurred most frequently (20 cases, 40.0%). Other causes included renal cyst (10 cases, 20.0%), autoimmune diseases (4 cases, 8.0%), bleeding diathesis (3 cases, 6.0%), and idiopathic renal hemorrhage (6 cases, 12.0%). Twelve patients (24.0%) received conservative management, 29 patients (58.0%) underwent interventional embolization therapy, and 11 patients (22.0%) received nephrectomy. The success rate on first embolization therapy was 86.2%(25/29), and approximately 13.8%(4/29) required second embolization therapy or nephrectomy.Conclusions:Spontaneous renal hemorrhage has no specific clinical features and is easy to be underdiagnosed or misdiagnosed. Non-contrast CT scan has a high diagnostic value for renal bleeding. Comprehensive judgement consisting of clinical features, laboratory tests, imaging manifestations and pathological examinations should be relied on for finding the underlying causes. Prompt diagnosis and management can guarantee a better prognosis.

Objective:To investigate the urinary sediment findings and the clinicopathologic features of IgA nephropathy (IgAN) patients with acute kidney injury (AKI).Methods:It was a retrospective study. The patients with renal biopsy-proven primary IgAN in Peking University First Hospital from January 31, 2013 to July 31, 2015 were selected. According to whether AKI occurred at renal biopsy or not, the patients were divided into AKI group and non-AKI group. Morning urine samples were obtained on the day of renal biopsy. Urine sediments, including various cells and casts, were examined. The clinical data, urinary sediments, and renal pathological changes were compared between the two groups. Logistic regression analysis was performed to identify the association between clinical pathological changes, urinary sediment indicators and AKI, or clinical pathological changes and urinary sediment indicators.Results:There were 502 IgAN patients enrolled in this study, with age of (36.1±12.1) years old and 261 males (52.0%). The incidence of AKI was 11.4% (57/502) among the enrolled patients at the time of renal biopsy. Common causes of AKI included gross hematuria-induced AKI (10 cases), acute tubulointerstitial nephritis (10 cases), crescentic IgAN (9 cases), malignant hypertensive renal damage (6 cases), and multiple etioloqy or unknown etiology (22 cases). Compared with non-AKI group, AKI group had higher proportions of males and malignant hypertension, higher levels of proteinuria and urinary erythrocyte counts, and higher frequencies of gross hematuria, leukocyturia, renal tubular epithelial cells, and granular casts (all P<0.05). AKI group also had higher proportions of severe tubular atrophy/interstitial fibrosis (T2) and cellular/cellular fibrous crescent formation (C2) than non-AKI group (both P<0.05). Logistic regression analysis results showed that, there were statistically significant differences in the correlation between AKI and gender, 24 h urinary protein, urinary erythrocyte counts, granular casts and renal tubular atrophy/interstitial fibrosis (T) scores (all P<0.05). Hematuria, leukocyturia, red blood cell casts, white blood cell casts, granular casts, and fatty casts were correlated with endothelial hypercellularity (E) and cellular/cellular fibrous crescent formation (C) scores, respectively (all P<0.05). Hematuria was correlated with mesangial hypercellularity (M) scores ( OR=2.613, 95% CI 1.520-4.493, P=0.001). Hematuria ( OR=1.723, 95% CI 1.017-2.919, P=0.043) and fatty casts ( OR=2.646, 95% CI 1.122-6.238, P=0.026) were correlated with segmental sclerosis or adhesion (S) scores. Leukocyturia ( OR=1.645, 95% CI 1.154-2.347, P=0.006) and fatty casts ( OR=2.344, 95% CI 1.202-4.572, P=0.012) were correlated with T scores. Epithelial cell cast was correlated with C scores ( OR=1.857, 95% CI 1.174-2.939, P=0.008). Conclusions:AKI is a common complication among IgAN patients with diverse etiology and more severe clinicopathological features. Urinary sediment findings can reflect renal pathological changes to some extent, and therefore assist in the clinical diagnosis and treatment of IgAN patients with AKI.