Spontaneous retroperitoneal hematoma and rectus sheath hematoma

INTRODUCTION — Spontaneous retroperitoneal hematoma (SRH) is defined as bleeding into the retroperitoneal space without trauma or iatrogenic manipulation [1]. Rectus sheath hematoma (RSH) results from accumulation of blood within the rectus sheath. Both conditions are rare but may mimic a number of acute intra-abdominal pathologies, warranting heightened suspicion and prompting diagnostic evaluation and management [2].

This topic will review the pathophysiology, diagnostic evaluation, and management of SRH and RSH. The evaluation of patients with abdominal pain from other conditions is discussed elsewhere. (See "Evaluation of the adult with nontraumatic abdominal or flank pain in the emergency department".)

Traumatic and iatrogenic causes of retroperitoneal hematoma are discussed in other topics. (See "Overview of the diagnosis and initial management of traumatic retroperitoneal injury" and "Periprocedural bleeding in patients undergoing percutaneous coronary intervention", section on 'Retroperitoneal space'.)

PATHOGENESIS

Spontaneous retroperitoneal hematoma — The retroperitoneum is a highly vascular space. Retroperitoneal hematoma can occur with trauma, surgical or other procedural manipulations, or spontaneously in patients who are on anticoagulation or antiplatelet therapy. They may also be a result of vascular retroperitoneal lesions such as cysts, aneurysms, tumors, or lipomas [3,4].

Additionally, gynecologic or obstetric conditions including ovarian torsion, hemorrhagic cysts, ectopic pregnancy, and serosal fibroids can present with spontaneous retroperitoneal bleeding [5]. In one series of 78 patients, the majority of noncoagulopathic spontaneous retroperitoneal hematomas were caused by gynecologic conditions [2]. (See "Management of hematomas incurred as a result of obstetric delivery", section on 'Retroperitoneal hematomas'.)

The pathogenesis of spontaneous retroperitoneal bleeding/hematoma is not entirely clear. Some suggest that the diffuse vasculopathy and arteriosclerosis of small retroperitoneal vessels renders them friable and prone to rupture [6]; others suggest that an unrecognized minor trauma in the microcirculation can cause a hemorrhage in the context of anticoagulation [7].

Rectus sheath hematoma — Rectus sheath hematomas (RSHs) arise from disruption of a branch of the inferior epigastric artery at its insertion into the rectus abdominis muscle combined with an inability to tamponade the bleeding [8].

The rectus abdominis muscle receives its blood supply from the superior and inferior epigastric arteries (figure 1). The inferior epigastric artery perforates the rectus abdominis muscle at the arcuate line, where the inferior epigastric artery is relatively fixed within the muscle, making its branches vulnerable to shearing forces [9]. (See "Anatomy of the abdominal wall", section on 'Inferior epigastric arteries'.)

The arcuate line, which is a horizontal line occurring one-third of the distance from the umbilicus to the pubic symphysis, demarcates the lower limit of the posterior rectus sheath (figure 2). Without a supporting posterior rectus sheath, the lower half of the rectus abdominis muscle is susceptible to changes associated with movement, which explains why a majority of RSHs occur in the lower abdomen [10,11]. (See "Anatomy of the abdominal wall", section on 'Rectus sheath'.)

Once a branch of the inferior epigastric artery is disrupted, bleeding ensues, and the inability to quickly tamponade the bleeding results in symptomatic RSHs.

RISK FACTORS — Several risk factors have been associated with the formation of spontaneous retroperitoneal hematomas (SRHs) and rectus sheath hematomas (RSHs), either by disrupting blood vessels within the retroperitoneum/rectus muscle or by interfering with coagulation.

●Anticoagulation or antiplatelet therapy – Patients who are on anticoagulation or antiplatelet therapy are at an increased risk of developing an SRH or RSH [8,12]. In most published series of SRHs and RSHs, about three-quarters of patients were on one or more anticoagulant or antiplatelet agents (range 50 to 89 percent) [1,2,4,13,14].

●Older adults and women – The median age of the patients of most published series of SRHs and RSHs was approximately 70 years [1,13]. RSH is more prevalent in women and older patients, presumably because they have a smaller rectus abdominis muscle mass and therefore are less capable of tamponading an RSH [8,15]. Pregnancy is an additional risk factor for the development of RSH in women, making women two to three times more likely than men to develop an RSH [3]. (See "Approach to acute abdominal/pelvic pain in pregnant and postpartum patients", section on 'Rectus sheath hematoma'.)

●Chronic medical conditions – Chronic medical conditions such as abnormal coagulation, hypertension, arteriosclerosis, cirrhosis, and renal disease have also been associated with an increased risk of SRH or RSH formation [3,8,10,13].

●Asthma or chronic obstructive pulmonary disease (COPD) – Medical conditions such as asthma or COPD can also predispose to RSH formation by causing vigorous contraction of the rectus abdominis muscle during coughing spells [3,8,10].

CLINICAL PRESENTATIONS

Spontaneous retroperitoneal hematoma — The most common complaint of a spontaneous retroperitoneal hematoma (SRH) is truncal pain [2]. In a series of 89 patients with SRH, the most common symptom was abdominal pain in 68 percent, followed by leg pain in 24 percent, hip pain in 23 percent, and back pain in 22 percent [1]. Approximately 10 percent presented with leg numbness or weakness, and 4 percent had a pulseless lower extremity from nerve roots and blood vessels compressed by the hematoma.

Other nonspecific symptoms, including syncope, altered mental status, lightheadedness or dizziness, chest pain, pallor, nausea, headache, dyspnea, or generalized weakness, may be attributed to hypovolemia or anemia due to acute blood loss [1]. In another series, 50 percent of the patients were hemodynamically unstable, but only 18 percent required pressor support [2].

Abdominal mass (8.8 percent) and flank discoloration (6.3 percent) were less commonly found than tenderness [1]. When recognized, however, the following classic dermatological findings can be extremely helpful in detecting concealed pathologies [2]:

●Grey Turner's sign (ecchymosis/discoloration of the flanks)

●Cullen's sign (periumbilical ecchymosis)

●Fox's sign (upper thigh along the inguinal ligament)

●Bryant's sign (blue discoloration of the scrotum)

●Stabler's sign (bruising of the pubis and groin)

Rectus sheath hematoma — Rectus sheath hematoma (RSH) most often presents as acute onset of abdominal pain with a palpable abdominal mass [8]. Additional findings may include fevers, chills, nausea, vomiting, abdominal tenderness, and abdominal guarding. Depending upon the size and location of the RSH, patients may also present with signs of hypovolemic shock or even abdominal compartment syndrome. (See "Abdominal compartment syndrome in adults".)

Physical examination findings that may help distinguish RSH from causes of acute intra-abdominal pathology include Carnett's sign and Fothergill's sign [3].

●Carnett's sign – To elicit a Carnett's sign, the point of maximal tenderness is identified on the abdominal wall with the patient supine, after which the patient is asked to sit up. A positive Carnett's sign is recorded if the site of maximal tenderness remains unchanged or increases [16]. The presence of a positive Carnett's sign suggests that the pain originates from within the abdominal wall, which is consistent with the diagnosis of an RSH. (See "Anterior cutaneous nerve entrapment syndrome".)

●Fothergill's sign - A positive Fothergill's sign is recorded if a patient's abdominal wall mass does not cross the midline and does not change with movement of the lower extremities, which is also consistent with the diagnosis of an RSH.

DIAGNOSIS AND EVALUATION — Spontaneous retroperitoneal hematoma (SRH) or rectus sheath hematoma (RSH) should be suspected in patients with acute-onset abdominal, leg, or back pain or a palpable abdominal mass (especially in the lower abdomen). The diagnosis is confirmed by abdominopelvic computed tomography (CT) with intravenous contrast [17]. Children and pregnant women suspected of having an SRH or RSH should undergo abdominal ultrasound or magnetic resonance imaging (MRI) in lieu of CT scan [18].

Serial hemoglobin or hematocrit levels should be obtained as the initial values may be normal, just as in other cases of acute bleeding [8]. All patients should have coagulation studies to ensure that they do not have an undiagnosed hematologic disorder and to direct resuscitation if they are on anticoagulation.

DIFFERENTIAL DIAGNOSIS — The main differential diagnoses of spontaneous retroperitoneal hematoma (SRH) or rectus sheath hematoma (RSH) in patients who present with abdominal pain are intra-abdominal pathologies. They can be readily distinguished by abdominal imaging studies as discussed above. (See "Evaluation of the adult with nontraumatic abdominal or flank pain in the emergency department".)

Patients should not undergo surgical exploration without imaging studies, as diagnosis of SRH or RSH by history and physical examination alone is only accurate in 17 percent of patients with acute abdominal pain [15,19].

CLASSIFICATIONS

Spontaneous retroperitoneal hematoma — The classic trauma literature categorizes hematomas in the retroperitoneum into three zones: central, lateral, and pelvic (see "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'Retroperitoneal zones'). However, unlike trauma or procedure-related retroperitoneal hematoma (RPH) where bleeding zones are discrete and a discrete bleeding vessel may be located, the bleeding source remains obscure in most cases of spontaneous retroperitoneal hematoma [2].

Rectus sheath hematoma — Rectus sheath hematomas (RSHs) are subclassified based upon CT scan findings to guide treatment [17].

●A type I RSH is small and confined within the rectus muscle. It does not cross the midline or dissect fascial planes (image 1). Almost all of these patients are hemodynamically stable without any change in serial hemoglobin or hematocrit levels. Patients are treated conservatively with bedrest, analgesia, compression of the hematoma, and reversal of anticoagulation when appropriate [8,10,11]. Treatment of type I RSH patients does not require hospitalization.

●A type II RSH is also confined within the rectus muscle but can dissect along the transversalis fascial plane or cross the midline (image 2).

●A type III RSH is large, usually below the arcuate line, and often presents with evidence of hemoperitoneum and/or blood within the prevesical space of Retzius (image 3).

Patients with type II or III RSH can present as hemodynamically stable or show signs of hemodynamic compromise (ie, altered mental status, hypotension, tachycardia, acute kidney injury, etc) with an abrupt or gradual decrease in hemoglobin or hematocrit. Such patients generally need to be observed in the hospital.

MANAGEMENT — Management of spontaneous retroperitoneal hematoma (SRH) and rectus sheath hematoma (RSH) is determined by the patient's clinical status and the underlying cause (eg, anticoagulation). In published case series, the majority of patients responded to medical therapy alone; up to one-quarter of patients will require angiographic intervention; fewer than 10 percent will require surgical intervention [1,2,4,13,14].

Medical therapy — Medical management includes volume support with intravenous fluids and/or blood products and reversal of anticoagulation [2]. Upon presentation, one-quarter to one-half of the patients will be hemodynamically unstable, thus requiring intensive care unit (ICU) monitoring [2,13]. However, only 18 percent required pressor support, according to one study [2]. Packed red blood cells or other blood products should be transfused when clinically indicated; 45 to 80 percent of patients required transfusion of blood products in large series [1,2,4,13,14]. (See "Indications and hemoglobin thresholds for RBC transfusion in adults".)

Angiographic or surgical intervention — Patients with hypovolemic shock that is refractory to aggressive resuscitation, ongoing transfusion requirement, expanding hematoma, or active contrast extravasation on CT imaging should be promptly referred for angiography with possible embolization of the bleeding source or surgery [8,10,11]. In large case series, angiography and surgery were required in 11 to 25 percent and 1 to 7 percent of patients, respectively [1,4,13].

At facilities that have interventional radiology capabilities, angiography with arterial embolization is often the first-line intervention for SRH/RSH. Surgery is generally reserved for patients with failed angiographic procedures, concurrent surgical conditions, compressive symptoms from hematoma formation (eg, femoral neuropathy or hydronephrosis), or abdominal compartment syndrome (rare) [1]. At those institutions that do not have interventional radiology capabilities, surgical intervention is the only option.

Surgical intervention — Surgical intervention includes ligation of the bleeding arterial vessel and evacuation of the hematoma.

For retroperitoneal hematoma — Since most SRHs overlie the psoas/iliacus muscles, they are typically approached surgically via a flank incision/kidney transplant incision, which also facilitates decompression of the nerve roots and avoids violation of the peritoneum.

By contrast, traumatic retroperitoneal hematomas are typically approached transperitoneally to allow for a full visceral rotation in case of a renal injury, extraperitoneal packing in case of pelvic retroperitoneal bleeding caused by a pelvic fracture, and repair of major vascular injury caused by a penetrating trauma. The approaches and techniques for control of a traumatic retroperitoneal hematoma further depend on the zone that the hematoma is in and are discussed in detail in another topic. (See "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'Exploration of retroperitoneal hematoma'.)

For rectus sheath hematoma — Surgical exploration is approached through a paramedian or midline incision with entrance into the rectus sheath overlying the largest component of the hematoma. Surgical exploration is typically guided by CT imaging. Evacuation of the hematoma is performed first in order to facilitate identification of the bleeding vessels. Once the bleeding vessel is identified, it is ligated. Ligation of either the superior or inferior epigastric vessel is well tolerated due to collateral flow from the other vessel on the same side and from both superior and inferior epigastric vessels on the contralateral side of the abdomen. Once hemostasis is achieved, any remaining hematoma is evacuated, the area is irrigated, and a large bore, closed suction drain is placed into the previous hematoma space. RSHs that require surgical intervention often create a large dead space. Therefore, it is our practice that any closed suction drain placed at the time of surgical intervention remains in place until the output is less than 30 cc/day [10,20,21].

Restarting anticoagulation — Resuming anticoagulation after SRH or RSH is a delicate matter. The clinician must balance the need for anticoagulation to prevent thromboembolic events with the risk of recurrent bleeding or hematoma enlargement. Although most would take these hematomas as an opportunity to reevaluate the appropriateness of anticoagulation, there are very few guidelines or even data on when to restart anticoagulation if it remains indicated:

●In a retrospective study of 156 anticoagulated patients with RSH, 62 percent restarted anticoagulants during the same hospitalization after a mean of 4 days (range 2 to 8 days) [22]. Aspirin was restarted in all patients after 2 days (range 1 to 4 days), antiplatelet agents in 50 percent after 6 days (range 2 to 13 days), and coumadin in 67 percent after 4 days (range 2 to 7 days). Five patients suffered thrombotic complications while awaiting resumption of anticoagulation, while two patients developed hematoma enlargement after resumption of anticoagulation.

●In a retrospective study of 34 patients with SRH (44 percent anticoagulated), 66 percent eventually restarted anticoagulation after a mean delay of 19 days (range 2 to 90 days); no patient suffered a new bleed [23].

Resuming anticoagulation in these patients will often be clinician dependent and should be based on (1) stabilization of hemoglobin levels, (2) there being no ongoing blood transfusion requirements, (3) there being no evidence of expanding retroperitoneal or rectus sheath hematoma, and (4) a low suspicion for the need for any additional procedural or surgical intervention. For patients on long-term anticoagulation, we recommend that their anticoagulation be resumed prior to discharge from the hospital under monitored conditions.

More data are available on restarting anticoagulation after either an intracranial bleed or gastrointestinal bleed. (See "Management of bleeding in patients receiving direct oral anticoagulants", section on 'Resumption of anticoagulation'.)

OUTCOMES — Spontaneous retroperitoneal hematoma and rectus sheath hematoma can be associated with high mortality but are typically not the direct cause of death. The larger series reported mortality rates that ranged from 6 to 22 percent [1,2,4,13,14]. However, much of the mortality can be attributed to comorbid conditions, and true independent predictors of mortality are difficult to identify in this heterogenous population of patients [4].

SUMMARY AND RECOMMENDATIONS

●Definitions – Spontaneous retroperitoneal hematoma (SRH) and rectus sheath hematoma (RSH) are rare clinical entities that result from accumulation of blood within the retroperitoneum and the rectus sheath, respectively, without trauma or iatrogenic manipulation. (See 'Introduction' above.)

●Pathogenesis – The pathogenesis of SRH is not entirely clear but may be related to rupturing of friable retroperitoneal blood vessels or unrecognized minor trauma in the context of anticoagulation. RSHs arise from disruption of a branch of the inferior epigastric artery at its insertion into the rectus abdominis muscle combined with an inability to tamponade the bleeding. (See 'Pathogenesis' above.)

●Risk factors – Risk factors of SRH/RSH formation include anticoagulation or antiplatelet therapy, female sex, advanced age, chronic comorbid medical conditions, and asthma or chronic obstructive pulmonary disease. (See 'Risk factors' above.)

●Diagnostic evaluation – SRH/RSH is suspected in patients with acute-onset abdominal, leg, or back pain or those with a palpable lower abdominal mass. Suspected patients should undergo abdominopelvic CT scan to diagnose and localize the hematoma and to exclude intra-abdominal pathologies. Children and pregnant women should undergo abdominal ultrasound or MRI instead. (See 'Clinical presentations' above and 'Diagnosis and evaluation' above and 'Differential diagnosis' above.)

Laboratory evaluation of SRH/RSH includes serial hemoglobin and hematocrit levels as well as coagulation factors. (See 'Diagnosis and evaluation' above.)

●Management – Management of SRH/RSH is based upon the patient's clinical status and the underlying cause and progresses in a stepwise fashion. In published case series, the majority responded to medical therapy alone; up to one-quarter of patients will require angiographic intervention; fewer than 10 percent will require surgical intervention (see 'Management' above):

•Most patients will respond to medical therapy alone, which includes volume support with intravenous fluids and/or blood products and reversal of anticoagulation, often in the intensive care setting. (See 'Medical therapy' above.)

•For patients with refractory hypovolemic shock, ongoing transfusion requirement, expanding hematoma, or active contrast extravasation on CT, we suggest angiographic rather than surgical intervention (Grade 2C). Surgical intervention is a reasonable alternative when angiographic procedures are not available or have failed, or when patients have concurrent surgical conditions, compression from hematoma formation (eg, femoral neuropathy or hydronephrosis), or abdominal compartment syndrome. (See 'Angiographic or surgical intervention' above.)

●Resuming anticoagulation – The decision to resume anticoagulation after SRH/RSH should be based on (1) stabilization of hemoglobin levels, (2) there being no ongoing blood transfusion requirements, (3) there being no evidence of expanding retroperitoneal or rectus sheath hematoma, and (4) a low suspicion for the need for any additional procedural or surgical intervention. The optimal timing is dependent on clinical situations, but anticoagulation should generally be resumed in the hospital under monitored conditions prior to discharge. (See 'Restarting anticoagulation' above.)