Rectus sheath hematoma (RSH) is an uncommon cause of an acute abdomen that can be a benign occurrence or quickly progress to a life-threatening event. It is important for the emergency physician to be knowledgeable about RSH because it can mimic many abdominal conditions.
RSH results from the accumulation of extravasated blood into the sheath enveloping the rectus abdominis muscles and is most commonly found in the right (60%) lower abdomen (80%). (Am J Surg 1946;71:689.) Bleeding occurs from rupture of the inferior or superior epigastric/mammary arteries or branches, a muscle tear, or in some cases, the deep circumflex iliac artery. Initially bleeding is confined to the rectus sheath but with continued bleeding, can dissect inferiorly into the preperitoneal space as a pelvic hematoma and laterally into the retroperitoneal space. Blood also may leak into the peritoneum if there is a peritoneal rupture. (Am J Surg 2006;191:126.)
Above the arcuate line, or linea semicircularis (a horizontal line approximately one-third the distance between the umbilicus and pubic symphysis where the inferior epigastric vessels contact the rectus abdominis), the posterior aspect of the rectus sheath is made of multiple strong aponeurotic fibers. Below the line, the rectus abdominis rests directly on the transversalis fascia only. Hematomas in this region can easily enlarge, cross the midline, and dissect down into the prevesical space of Retzius. (Townsend et al. Sabiston Textbook of Surgery. 17th ed. Philadelphia, PA: Elsevier; 2004:1178.) Therefore, the shape of the hematoma may vary based on location. Above the arcuate line, they tend to be ovoid, and below the arcuate line, they tend to be spherical because the hematomas can expand extensively into the extraperitoneal space, spreading inferiorly, laterally, and posteriorly. (J Clin Ultrasound 2001;29:306.)
RSH bleeding can be spontaneous, most commonly secondary to anticoagulation therapy (Am J Roentgenol 2007;188:W497) or the result of direct trauma (i.e., recent or remote intra-abdominal procedures, motor vehicle crash, sporting activity, surgery, or acupuncture). Cases of spontaneous RSH have been reported to occur as a result of increased intra-abdominal pressure from coughing, sneezing, or childbirth; coagulation disorders; and intra-abdominal injections; and in patients with cirrhotic liver disease, influenza, typhoid fever, or an underlying abdominal wall abscess.
One institution's review of their 126 RSH cases showed that 64 percent occurred in women, for a female-to-male ratio of 1.8:1. The mean age was 67.9 years (median, 73 years; range, 18–97 years). (Medicine 2006;85:105.) It is postulated that one reason for the sex difference is that women tend to have less rectus muscle mass.
The presentation of RSH can mimic many intra-abdominal processes that can make the diagnosis challenging. Patients may complain of vomiting, nausea, and fever. Symptoms can range from slight abdominal pain to hypovolemic shock, but abdominal wall pain associated with a mass (Fothergill sign) is the most consistent finding at presentation. (Medicine 2006;85:105.) A large body habitus, however, may not render the mass palpable.
Patients with RSH should have a positive Carnett's sign, a clinical test to differentiate pain originating from the abdominal wall versus pain arising from an intra-abdominal source. With the patient supine, the site of maximal abdominal tenderness is identified. The patient then sits halfway up. If local palpation at the same site causes increased pain, the test is positive, meaning that the abdominal mass is fixed with contraction and located in the abdominal wall. If the pain with palpation at the identified site is alleviated when the patient sits halfway up, then the source is likely to arise from the abdominal viscera, and the contracted rectus muscle is protecting the intra-abdominal contents. (Postgrad Med J 2002;78:755.) Some may have flank (Grey-Turner's sign) or periumbilical ecchymosis (Cullen's sign), which does not differentiate between a retroperitoneal or abdominal wall hemorrhage.
RSH is known to mimic various conditions such as acute cholecystitis, appendicitis, ruptured abdominal aortic aneurysm, sigmoid diverticulitis, sepsis (Heart Lung 2006;35:434), peptic ulcer disease, bowel obstruction, ovarian cyst/torsion, pancreatitis, ectopic pregnancy, abdominal wall abscess, abruptio placenta (Am J Surg 2006;191:126), and can represent a diagnostic dilemma, particularly with an initial incorrect diagnosis made in 51 percent of the reported cases in pregnant women. (J Clin Ultrasound 2001;29:306.)
The best diagnostic modality to evaluate a suspected RSH is an abdominal computerized tomography (CT) scan, which is more specific than ultrasonography. (Abdom Imaging 1996;21:62.) Sonographic findings are nonspecific in some cases, and can mimic abdominal wall tumors and inflammatory diseases. (Am J Roentgenol 2007;188:W497.) Digital subtraction angiography is the most useful imaging technique to identify active bleeding. It provides information about the number of bleeding sites and their exact location. (Am J Roentgenol 2007;188:W497.) A complete blood count, coagulation studies, type, and crossmatch should be considered for all patients.
Management depends on the etiology of the lesion, the patient's hemodynamic status, and whether the hematoma is stable or expanding. The natural course of most RSHs is typically self-limited as the bleeding tamponades itself, and management is usually conservative. (Am J Roentgenol 2007;188:W497.) RSH not invading the prevesicular space or peritoneum in a stable patient will often resolve nonoperatively with rectus rest, correction of any predisposing factors (J Vascular Surgery 2004;39:250), compression, and ice.
Large hematomas resulting in hypovolemia require emergent management, necessitating a prompt and accurate diagnosis, anticoagulation reversal, fluid resuscitation or transfusion, and hemodynamic stabilization. If bleeding continues, some require more invasive interventions including surgical evacuation of large hematomas and ligation of bleeding vessels.
Percutaneous management by selective transcatheter arterial embolization also may be a therapeutic option. (Am J Roentgenol 2007;188:W497.) In the largest documented case series so far, eight percent of patients required arterial embolization, two percent required surgical intervention, and all others responded to conservative management. (Medicine 2006;85:105.) Needle aspiration of hematomas is generally not recommended. Hospital admission depends on the size of the lesion, the patient's hemodynamic status, and other comorbidities.
Although RSH is usually a benign self-limiting condition, it may be fatal (approximately 2% in one case series). (Medicine 2006;85:105.) The mortality rate for iatrogenic RSH is reported to be 18 percent, while the mortality rate for patients with RSH who are undergoing anticoagulation therapy is reported to be 25 percent. Pregnant patients have a reported mortality rate of 13 percent, with a 50 percent mortality rate for the fetus.
This patient required blood products and embolization of the right inferior epigastric vessel because of persistent hypotension. Of note, abdominal paracentesis is generally a very safe procedure with a major bleeding complication rate of 0.9 percent. (Intern Med 1986;146:2259.)