Changing etiology and management patterns for spontaneous renal hemorrhage: a systematic review of contemporary series

To conduct a systematic literature review on spontaneous renal hemorrhage (SRH) in a contemporary cohort describing patterns in etiology and treatment. A systematic search of MEDLINE and CENTRAL databases was conducted to include articles, including case reports and case series on SRH published from 2000 to 2016. Full-text manuscripts were reviewed for clinical parameters which were collated and analyzed with univariate methods. Seventy-nine publications met inclusion criteria, reporting on 102 cases. Renal neoplasms (56.9%) and polyarteritis nodosa (PAN) (11.8%) remained as the most common overall and vascular causes of SRH, respectively. Angiomyolipoma (AML) was the most common causative renal neoplasm (74.1%), and patients were more likely to be female and present with macroscopic hematuria than those with vasculitis, while malignant neoplasms were more common in men. Proportions of SRH due to malignant neoplasms (specifically renal cell carcinoma, RCC) were reported less than PAN. Among this contemporary series, transarterial embolization (TAE) was most commonly used for acute SRH (42.2%). Renal neoplasms remain as the most common cause of SRH, of which AML predominates, while PAN is currently the second most common etiology in acute SRH, replacing RCC. Minimally invasive approaches, such as TAE and conservative/medical management, were preferred to initial surgery. PROSPERO registration number CRD42017069222.