28. Causes factor IX ,X deficiency, von Willebrand APL syndrome anticoagulation* *0.6-6.6% of patients undergoing therapeutic anticoagulation. Management of Spontaneous and Iatrogenic Retroperitoneal Haemorrhage: nt J Clin Pract. 2008; Injury ( to bony structures, major vessels, intestinal or retroperitoneal viscera) Iatrogenic