Retroperitoneal hematoma is defined as bleeding into the retroperitoneal space. This clinical entity is often occult and under-recognized by clinicians and is a cause of significant morbidity and mortality. Often patients do not manifest clinically apparent signs and symptoms until a substantial amount of blood loss has occurred. It is not uncommon for patients to present in frank hemorrhagic shock due to an underlying retroperitoneal hematoma. The retroperitoneal space lies directly posterior to the peritoneal cavity. An organizational schema dividing the retroperitoneal space into three different “zones” is widely prevalent in the surgical literature. The central-medial zone (Zone I) falls between the two psoas muscles and contains midline structures such as the abdominal aorta, inferior vena cava, pancreas, and duodenum. The perirenal zone (Zone II) begins lateral to the psoas muscles on either side and contains the kidneys, ureters, and portions of the colon. The pelvic zone (Zone III) includes the bladder as well as a multitude of vascular structures, including a robust network for presacral veins. Also, the retroperitoneum contains vital musculoskeletal structures such as the psoas muscles, vertebra, quadratus lumborum, and iliacus muscles. It houses connections to the diaphragm and bony pelvis. The term “retroperitoneal hematoma” comprises several distinct clinical entities that are best characterized according to their underlying mechanisms. The easiest way to dichotomize this diagnosis is to classify retroperitoneal hematoma as traumatic versus nontraumatic. The traumatic retroperitoneal hematoma heading can be further subdivided into penetrating versus blunt. The nontraumatic retroperitoneal hematoma category can be further broken down into spontaneous and iatrogenic. The diagnosis of retroperitoneal hematoma requires a high degree of clinical suspicion. In almost all cases, it is reliant upon the use of computed tomography (CT) scanning, which is often useful to confirm the diagnosis as well as identify the underlying cause. Treatment modalities include observation, interventional radiology coiling/embolization, and operative management for unstable patients.
Mondie, C., Rentea, R. M. Retroperitoneal Hematoma StatPearls , (2020).