Continuing Education Activity

Retroperitoneal bleeding occurs when blood enters into the space behind the posterior reflection of the abdominal peritoneum. With a variety of possible etiologies and patient presentations, the diagnosis of retroperitoneal bleeding can be difficult. Prompt evaluation and knowledge of the appropriate interventional strategies are key to improving patient outcomes from this moribund condition. This activity describes the basic approach to the evaluation and management of retroperitoneal bleeding and highlights the vital role of the interprofessional healthcare team in managing this complicated condition.

Objectives:

• Identify the etiology of retroperitoneal bleeding.
• Describe the evaluation of retroperitoneal bleeding.
• Outline the management options available for retroperitoneal bleeding.

Introduction

Retroperitoneal bleeding occurs when blood enters into space immediately behind the posterior reflection of the abdominal peritoneum. The organs of this space include the esophagus, aorta, inferior vena cava, kidneys, ureters, adrenals, rectum, parts of the duodenum, parts of the pancreas, and parts of the colon. Variability in presentation and etiology makes diagnosis quite difficult.[1] One common constellation of symptoms includes abdominal, back, flank, or groin pain; a palpable abdominal mass; and shock.[2]

Management is grounded in rapid diagnosis of bleeding, ongoing resuscitation with frequent reassessments, computed tomography for further diagnostic characterization, angioembolization for ongoing bleeding, and open surgical intervention for unstable patients or those with certain traumatic indications. Retroperitoneal bleeding is a deadly condition with anywhere from 6% to 22% of those affected.[3][4] Rapid diagnosis and treatment amongst a team of seasoned acute care personnel is key to patient survival.

Etiology

Complicating the diagnosis of retroperitoneal bleeding is a myriad of etiologies. The most commonly described initial delineation of causes is whether a patient’s bleeding is associated with trauma or not.[2][3][4]

Traumatic causes include penetrating and blunt trauma, typically of the abdomen and pelvis, whereas non-traumatic causes are divided into those occurring spontaneously and those not occurring spontaneously. Spontaneous etiologies are more varied and include patients undergoing anticoagulation or those on fibrinolytic therapy. Patients with hemorrhagic pancreatitis, renal or adrenal malignancies, gynecological complications, and aneurysmal dilations of the aortic and renal arteries may also experience spontaneous hemorrhage into this potential space.[5]

Nonspontaneous causes include iatrogenic injury during aortic and femoral artery cannulation or direct injury during abdominal or pelvic exploration.[6][7]

Epidemiology

Damage to retroperitoneal structures following abdominal trauma is common. Authors have reported some 20% to 33% of patients with penetrating trauma, and 44% to 80% of those with blunt trauma experience retroperitoneal injury with an overall associated mortality rate of 18% to 60%.[2][3][8]

Spontaneous hemorrhage is a considerably more rare phenomenon. Clinical trials of anticoagulation-induced hemorrhage of the retroperitoneum have documented a rate of 0.6% to 6.6%, with mortality occurring in 20%. In one study, following a percutaneous coronary intervention, iatrogenic retroperitoneal bleeding was noted in 0.57% of patients with an associated mortality rate of 10.4%.[9][10]

History and Physical

Retroperitoneal bleeding is a life-threatening condition. Diagnosis is made difficult even for the astute clinician as the presentation can be variable and nonspecific. Accurate diagnosis requires a high clinical index of suspicion as well as an accurate and focused history and physical examination. Rapid elucidation of recent trauma, known malignancy, recent surgical procedures, history of aneurysmal disease, current use of anticoagulation, and ongoing pancreatitis are keys to narrowing a wide differential diagnosis.[1]

The most common presentation of bleeding into the retroperitoneal space is abdominal or flank pain.[5][9] This may be accompanied by femoral nerve palsies in 20 to 30% of cases or radiation of pain into the groin or pelvis. Presentation exists on the spectrum of hemorrhagic shock with patients demonstrating anxiety and tachycardia early on in the disease process and hypotension, confusion, and hypothermia later. Physical examination in some cases may demonstrate the “Wunderlich syndrome” described as abdominal, back, flank, or groin pain, a palpable abdominal mass, and shock.[9][11]

Eponyms abound in the description of abdominal bleeding and are of use in a minority of cases. Grey-Turner’s sign occurs with the development of a hematoma along the lateral abdominal wall secondary to perirenal space bleeding tracking along with the quadratus lumborum. Cullen’s sign is a periumbilical ecchymosis that develops when retroperitoneal bleeding dissects along the falciform ligament anteriorly. Fox’s sign is ecchymosis of the anteromedial thigh from blood tracking along the psoas and iliacus muscles’ fascial planes. Bryant’s sign occurs when the scrotum fills with blood and becomes ecchymotic from abdominal bleeding tracking along the spermatic cord. Finally, Stabler’s sign is the development of a hematoma and bruising overlying the inguinal ligament.

In some cases, symptoms may be absent or overshadowed by other distracting injuries, particularly in trauma. Here, careful attention to the mechanism of injury and commonly associated injuries must be paid. Genitourinary involvement of bleeding may manifest as hematuria, while oliguria may develop from adjacent extrinsic compression by a developing hematomal mass. Additionally, pancreaticoduodenal involvement can present with gastric outlet obstruction.

Evaluation

The single most useful laboratory measurement to narrow the differential diagnosis towards retroperitoneal bleeding is falling hemoglobin; however, it must be emphasized that patients bleed whole blood, so it may take some time with or without crystalloid volume resuscitation to recognize this acute hemorrhagic anemia. Other useful studies include prothrombin time, partial thromboplastin time, international normalized ratio, and thromboelastography to identify a patient’s anticoagulation status. Urine analysis can evaluate for urinary tract involvement. If bleeding is suspected or ongoing, a blood type and crossmatch is essential.

The focused assessment with sonography for trauma (FAST) has profoundly altered the approach to diagnosis and management of abdominal trauma. Unfortunately, one well documented profound shortcoming of abdominal ultrasonography is the inability to effectively evaluate the retroperitoneal space. Because of this, ultrasound remains an incredibly useful tool in evaluating for concomitant free fluid in the peritoneal space, but cannot be reliably used to rule in or out retroperitoneal bleeding. The FAST exam is also limited in several other ways.[12] It is unable to identify an intraperitoneal fluid volume less than 200ml, nor can it differentiate between different types of fluid such as blood, urine, or stool.[13]

Also common in the trauma bay are the routine cervical, chest, and pelvic roentgenograms. A pelvic fracture may be the clinician’s first indication that the inferior retroperitoneum is involved; however, outside of the trauma setting, roentgenograms lack usefulness. The computed tomographic (CT) cross-sectional imaging of the abdomen with intravenous contrast has been identified as the superior study for narrowing the broad differential associated with retroperitoneal bleeding. CT can easily, rapidly, and repeatedly identify the specific hematomal location, concomitant injuries, and determine if bleeding is ongoing.[14][15]

CT examination is not without its negatives. The scan utilizes ionizing radiation, which can predispose a patient to develop cancer at a later date. The use of intravenous contrast can cause an acute kidney injury. Evaluation of pregnant women and children should emphasize studies that forgo the use of ionizing radiation such as abdominal ultrasonography and magnetic resonance imaging.

Treatment / Management

The treatment of retroperitoneal bleeding can be thought of in a stepwise approach from nonoperative management to angioembolization or, in severe cases, surgical intervention. The determination of the specific treatment strategy is dependent on several factors, including the location of the retroperitoneal bleeding, the patient’s stability, and the etiology of the bleeding. In all cases, regardless of whether or not trauma has proceeded the initiation of bleeding, initial resuscitation must begin with the use of the “ABCDE’s” of trauma. Simultaneous to the implementation of this algorithmic resuscitative approach, the search for the etiological cause and assessment of patient stability is undertaken. If at any time, the patient is noted to be hemodynamically unstable or demonstrate peritoneal signs, an urgent surgical intervention must be considered. Other indications that warrant immediate surgical intervention in trauma are based on the location of bleeding, which will be discussed here.

The retroperitoneum has been described as having three anatomical zones. Zone 1 is centrally located in the upper retroperitoneum and includes the aorta, inferior vena cava, pancreas, esophagus, and duodenum; zone 2 is located laterally to zone 1 and includes the ascending and descending colon, the kidneys and their ureters, and the adrenal glands; finally, zone 3 is located across the inferior portion of the retroperitoneum and contains the iliofemoral vessels as well as the rectum.

When retroperitoneal bleeding has been identified in trauma, the mechanism guides management. With penetrating trauma, zones 1 and 3 should be immediately surgically explored in all cases. Zone 2 is explored if bleeding is noted to be ongoing. In blunt trauma, zone 1 is always explored, and zone 2 is explored if bleeding is noted to be ongoing; however, if zone 3 bleeding is identified, surgical intervention should not be attempted in the setting of blunt trauma as the typical source is a pelvic fracture and associated venous plexus bleeding. Here, exploration can worsen bleeding by disrupting partially formed coagulum and removing hematomal tamponade.

Next, we will briefly discuss the primary survey of trauma resuscitation. The primary survey can be easily remembered using the “ABCDE” mnemonic. This begins with an assessment of the patient’s airway, “A,” to determine if it is patent. This is followed immediately by confirmation that the patient is breathing, “B.” If either a patient’s airway or breathing has been compromised, rapid intubation should be performed to maintain sufficient oxygenation and ventilation. Next, “C” stands for the obtainment of vascular access and maintenance of circulation. Massive transfusion protocol should be initiated early if bleeding is profound, especially if a patient’s presentation is concerning for hemorrhagic shock. Fluid resuscitation should follow trauma guidelines with no more than two liters of crystalloid fluid administration before transfusing packed red blood cells, platelets, and plasma in a 1 to 1 to 1 ratio.[16]

Assessment of patient disability, “D,” then occurs and includes performing a Glasgow coma scale, spine sweep, and assessing pupils for size and reactivity to light. Finally, one must completely expose “E,” the patient’s skin, and remove their clothing to complete a comprehensive physical exam. In the context of retroperitoneal bleeding, the emphasis is paid to the abdominal exam. The astute clinician must also elucidate a focused history, typically described with the acronym “SAMPLE,” consisting of the patient’s symptoms, allergies, medications, past medical history, last meal, and events proceeding their presentation. Reversal of anticoagulation, administration of blood products, and identification of concurrent pathology are paramount to the initial assessment.

If bleeding is ongoing and the patient is sufficiently stable, angioembolization may be employed. During this procedure, a catheter is introduced into a more peripheral artery, most commonly the femoral artery, and advanced in a retrograde manner to the area of suspected bleeding. Radiopaque contrast is infused, and image processing, such as digital subtraction angiography, allows the vascular flow and potential extravasation of contrast to be identified. The benefit of defining vascular injury with interventional angiography over CT angiography or magnetic resonance angiography is the possibility for immediate intervention. Once an injury is identified, hemostasis is achieved through the use of coil or particle embolization. Repeat contrast investigation demonstrates cessation of bleeding.[17][18]

For all patients with retroperitoneal bleeding, especially those managed nonoperatively, frequent reassessments are paramount to successful outcomes. Nonoperative management includes the reversal of anticoagulation, crystalloid and blood product resuscitation, serial abdominal examinations, and etiological identification of bleeding. Once an underlying cause is known, it should be reversed or corrected if possible. During all stages of the resuscitative process, careful attention must be paid to the patient’s vital signs, particularly blood pressure and heart rate, as retroperitoneal bleeding can be a dynamic process from which patients may deteriorate despite resuscitative efforts.[19]

Differential Diagnosis

Injury to the retroperitoneum can result in damage to any of the organs of this space including the adrenal glads; aorta; inferior vena cava; second and third parts of the duodenum; pancreatic head, neck, and body; ureters; ascending and descending colon; kidneys; esophagus; and rectum. These injuries may exist in isolation or, especially in the case of trauma, exist with other retroperitoneal, abdominal, spinal, or pelvic injuries.[2]

When spontaneous retroperitoneal bleeding is identified, the search for concomitant pathology that may be the source of the bleeding must ensue. This includes assessing for anticoagulation use, recent fibrinolytic therapy, renal masses, adrenal masses, gynecological complications, pancreatitis, or aortic and renal aneurysms.[4][5][6]

In the event of iatrogenically induced retroperitoneal bleeding, the specific location of bleeding must be identified. Here, the specific catheterization pathway utilized by the performing proceduralist must be sought as the nidus of bleeding initiation will most likely have initiated along this pathway. A complete vascular analysis is key to assess for vascular rupture, dissection, pseudoaneurysm, fistula, or wall hematoma.

Prognosis

Traumatic retroperitoneal hemorrhage has a high associated degree of mortality, with an overall rate of approximately 18%. More deadly injuries were identified to be those from blunt trauma, injuries of two or more retroperitoneal zones, and those who received surgical intervention more than 6 hours after injury.[3]

As the causes of spontaneous retroperitoneal bleeding are diverse and wide-ranging, so too are the clinical outcomes. A large majority of patients will respond to medical management alone. Of those with ongoing bleeding and worsening symptoms, approximately 25% will receive angiographic therapy as definitive management, and an additional 9% will need surgery. All-cause mortality ranges from as low as 6% to as high as 22% overall.[5][6][9] The most common location of spontaneous retroperitoneal bleeding is Zone 3 and those that die while suffering a bleed, typically due so to another condition occurring in conjunction with their bleeding.[20]

Complications

There are a variety of complications that can occur as a result of retroperitoneal bleeding. Here a brief list is provided based on the original insult and most common sequelae. Complications from hematomal formation mass effect include pelvic/ femoral neuralgia, small bowel obstruction, urinary obstruction, and gastric outlet obstruction.[11]

Complications from the associated hypotension, hypovolemia, and shock that can develop with severe retroperitoneal bleeding include myocardial infarction, acute kidney injury, acute liver injury, diffuse cerebral hypoperfusion, global hypoxia, and bowel necrosis.[9]

Complications of surgical intervention include infection, damage to adjacent structures of the operative field, and worsening of bleeding. Complications of angioembolization include infection, damage to the vasculature, worsening of bleeding, contrast-induced nephropathy, and ischemia of embolized arterial distributions.

Deterrence and Patient Education

Retroperitoneal bleeding is a serious illness that occurs when blood enters into space in the back of the belly. This usually occurs after a traumatic injury and may require surgery to fix. Sometimes the bleeding occurs because of cancer, the use of blood thinners, abnormal enlargement of blood vessels, or other diseases of the belly. As is the case with all procedures, unintentional bleeding can occur. Surgeries on the abdomen or surgeries that examine the arteries of the heart can cause bleeding into this retroperitoneal space and may require hospital admission and potentially further procedures to correct the problem.

Patients should see their primary care doctor regularly and be careful to take their blood pressure and blood-thinning medications as prescribed. Men over age 65 who have smoked should undergo a one-time screening ultrasound of their aorta to assess for enlargement.

Pearls and Other Issues

The Wunderlich Triad of spontaneous renal hemorrhage is a combination of abdominal, back, flank, or groin pain, a palpable abdominal mass, and shock.

The FAST exam cannot reliably evaluate the retroperitoneal space.

Treatment for retroperitoneal bleeding escalates with a worsening clinical presentation from nonoperative management to angioembolization to surgical intervention.

The retroperitoneal zones determine management in traumatic retroperitoneal bleeding. Penetrating trauma: Zone 1 and 3 are explored. Zone 2 is explored if ongoing bleeding. Blunt trauma: Zone 1 is explored. Zone 2 is explored if ongoing bleeding. Zone 3 is not explored.

Enhancing Healthcare Team Outcomes

A team-based approach to the management of retroperitoneal bleeding is vital to ensuring the best possible patient outcomes. Necessary hospital personals include an immediately available 24-hour emergency team trained in managing the complicated trauma patient as well as a patient in acute hypovolemic or hemorrhagic shock. This acute care team contains a diverse complement of vital individuals such as ambulance personal, imaging technologists, respiratory therapists, nurses, pharmacists, and residents. Rapid access to a vascular surgeon with advanced endovascular skills as well as a trauma surgeon comfortable with complicated visceral rotations and retroperitoneal access is also vital. An excellent relationship with the local blood bank and the ability to rapidly initiate a massive transfusion protocol is necessary when bleeding is profound.

Necessary hospital resources include EMS personal, bedside ultrasound, rapid CT access, and fully equipped endovascular and operating suites.[21]