Spontaneous retroperitoneal bleeding: a case series

BACKGROUND: We experienced four Japanese patients with spontaneous retroperitoneal bleeding, a rare disease. We categorized the clinical characteristics of spontaneous retroperitoneal bleeding in these patients treated in our hospital and discuss the risk factors of spontaneous retroperitoneal bleeding. CASE PRESENTATION: Three of the 4 patients did not have a bleeding tendency as indicated by laboratory data obtained at the time of retroperitoneal bleeding. The causative blood vessels were the lumbar and superior gluteal arteries and the internal iliac artery. All patients were receiving an anticoagulant, heparin in one and nafamostat mesilate in the other three patients. Three patients were being treated with hemodialysis or continuous hemodiafiltration when the spontaneous retroperitoneal bleeding occurred. We achieved hemostasis with transcatheter arterial embolization in 3 patients and with surgical hemostasis in 1 patient. CONCLUSIONS: We suggest that in patients receiving anticoagulant therapy in whom progressive anemia and unstable vital signs are present, spontaneous retroperitoneal bleeding should be considered as a possible cause. Nafamostat mesilate may be one of the risk factors for spontaneous retroperitoneal bleeding.