A hematoma is a blood collection in an extravascular space. It results from bleeding from a vascular structure. Depending on the location of the blood collection, hematomas are named accordingly, e.g., intra-cranial hematoma, hemothorax, pelvic hematoma, and abdominal hematoma. Hematomas can collect in extravascular areas near bleeding vessels with space to accommodate this blood collection. An abdominal hematoma can be intrabdominal or abdominal wall hematoma. Abdominal wall hematoma usually results from bleeding inside the muscle layers of the abdominal wall, most commonly the vascular rectus muscle. A known category of this hematoma is rectus sheath hematoma. This activity will be focused on rectus sheath hematoma or rectus hematoma.
Rectus sheath hematoma is bleeding in the rectus sheath. It is a confined space where the blood collects, commonly in the form of localized hematoma. Inferior or superior epigastric arteries and veins or their branches and tributaries form the basis of the bleeding source. A rectus hematoma can occur spontaneously in certain categories of people. But, it usually follows an injury to the inferior or superior epigastric vessels or their perforating branches. While this condition does resolve on its own, sometimes the hematoma can be extensive and lead to hypovolemic shock .
Rectus sheath hematomas result from bleeding of the epigastric vessels or their perforator branches in the rectus abdominis muscle sheath. Although rarely life-threatening, they can be severe and lead to hemodynamic instability. However, in most cases, rectus hematoma is self-limiting and usually spontaneously resolves.
Like in other types of bleeding, the cause can be due to the bleeding tendency, anticoagulation, or injury to the vessels. Vascular injury may occur due to external abdominal trauma, trauma during surgery (iatrogenic), or intense contraction of the rectus muscles during activities associated with Valsalva maneuver as in severe retching, vomiting or straining . In most cases, the hematoma is localized. But in people with excessive loose connective tissue, the hematoma can spread to above the umbilicus, the contralateral side or become intra-abdominal. Risk factors include the use of anticoagulant medications, advanced age, female gender, and intense physical activity. With the increased use of anticoagulation, the rates of rectus sheath hematoma appear to be on the rise.
Rectus sheath hematomas are uncommon . The exact incidence of rectus sheath hematoma is not known as the condition is often misdiagnosed or undiagnosed. Some studies report an incidence of 1.5% to 2% in hospitalized patients.
Overall, rectus sheath hematoma is more common in females than males. A higher female incidence has been linked to decreased muscle mass. While pregnancy is a risk factor in women, in men trauma and exercise seem to be the most common causes. Rectus sheath hematomas are more common on the right side, and the majority are located in the lower quadrant of the abdomen below the arcuate line.
Rectus sheath hematoma is caused by rupture of an epigastric artery or one of its perforating branches. The vessel injury may be due to blunt or penetrating trauma, surgery, or strong contractions of the rectus muscle. Since the epigastric arteries run deep along the posterior rectus sheath, making a diagnosis during a physical exam is difficult especially in obese patients. The hematoma is usually posterior to the rectus muscle fibers, subcutaneous fat, and skin. Palpating a tender firm bulge is the most common physic exam finding. Fluctuation sign of fluid collection is not usually possible to detect due to the deep location of the hematoma. The lower quadrants of the abdomen are usually involved because of the long epigastric branches and the lack of a tamponade effect from the loose connective tissues of the rectus sheath.
History and Physical
The typical presentation of a rectus sheath hematoma is that of abdominal pain and its associated symptoms like nausea and vomiting. The pain is often sudden in onset, sharp and does not radiate. In extremely rare cases, the hematoma may be large and present with hypovolemia, tachycardia, and tachypnea. Physical exam usually reveals a palpable localized mass which is non-pulsatile. The Fothergill sign (mass in the abdominal wall that does not cross the midline and does not change with flexion of the rectus muscles is suggestive of a rectus sheath hematoma) is useful to determine if the abdominal mass is within the abdominal wall or intra-abdominal cavity. It is not a highly sensitive sign and is often inconclusive in obese individuals.
The clinician should obtain a thorough medical history to determine the presence of any risk factors like surgery, coughing, constipation, asthma, bronchitis, anticoagulation therapy and use of oral anticoagulants and steroids.
Ultrasound is the first test of choice to confirm the diagnosis of a rectus sheath hematoma after basic blood work, and coagulation profile are obtained. The hematoma appears as hypoechoic space in the posterior rectus sheath. Further information like the size and exact location of the hematoma can be obtained from the ultrasound study. If the ultrasound study is inconclusive, a CT scan is the next test. It can show more details about the location, size, and extension of the hematoma. When intravenous contrast is administered with the CT scan, active bleeding can be detected by the presence of the contrast in the form of blush in the hematoma if the bleeding is active.
Unless a contrast is visualized in the hematoma, the differential diagnosis of a fluid collection in the rectus sheath should not be ignored. If the diagnosis of hematoma is still in doubt after imaging, needle aspiration can be performed to differentiate a hematoma from an abscess. However, with needle aspiration, there is a risk of puncture the bladder, bowel, or a hernia.
Evaluation of the hematoma should be part of the comprehensive evaluation of the patient condition. General assessment with addressing the related factors and conditions causing the hematoma or as a complication of the hematoma is necessary for a proper evaluation. Simultaneous treatment of the underlying condition and the possible or pending complications is mandatory for successful management.
Conditions presenting with a mass:
- Abdominal wall tumors (benign an malignant).
- Abdominal wall abscess.
- Abdominal wall hernia.
Conditions presenting pain or acute abdomen:
- Peptic ulcer disease.
- Bowel perforation.
- Tubo-ovarian abscess.
- Urinary tract infection.
A comprehensive history, physical exam and work up with a low index of suspicion will usually identify the pathology, confirm the diagnosis and assist in the management planning.
Most cases of rectus hematomas are self-limited, non-life-threatening, and can be identified and treated successfully with minimal interventions. Even though, fatalities have been reported. Most of the fatality cases have come to light during an autopsy. Rectus sheath hematoma mortality is higher in elderly individuals who are on oral anticoagulants. Another population group that is at higher risk for mortality are pregnant women. Anecdotal old reports reveal a mortality rate of 15% in the mother and nearly 50% in the fetus. However, it is important to know that these data were collected before the wide use of ultrasound and CT scan. Today, these imaging modalities can rapidly diagnose the condition.
The main consequence of undiagnosed or untreated rectus hematomas is pain. In addition to pain, severe bleeding is serious and can be life-threatening. Therefore sever bleeding should be promptly identified and aggressively treated. Another potential complication is abscess formation. As in any blood collection that is not drained, there is always a chance of superseding infection and development of an abscess. Draining of abscess becomes mandatory when it develops.
Postoperative and Rehabilitation Care
Follow up and reassessment including physical activities adjustment to prevent recurrent and further tissue damage. Patients should be advised to avoid indulging in heavy exercises. The decision to restart oral anticoagulation requires clinical judgment and balance between the indication of anticoagulation treatment and possible rebleeding in the rectus sheath.
Rectus hematoma is a surgical condition. Once a patient has been diagnosed with a rectus sheath hematoma, surgical consultation should be made. Interventional radiology and hematology specialties may be needed depending on the severity and or the underlying condition.
Pearls and Other Issues
- Rectus sheath hematoma is an uncommon disorder.
- It can be confused with other abdominal wall pathologies like tumors or hernias.
- Ultrasound or CT scan can assist in confirming the diagnosis.
- Many patients are on oral anticoagulation therapy. This should be held.
- The condition is usually treated conservatively with pain control and supportive treatment.
- In a few cases, arterial embolization or surgical intervention are required to stop the bleeding.
Enhancing Healthcare Team Outcomes
Abdominal wall hematoma can occur from a variety of causes. The patient often presents with abdominal pain which can be mistaken for a number of abdominal pathologies; hence an interprofessional approach to management is necessary. Nurses should be aware of and familiar with abdominal hematomas as they can occur from repeated LWMH or insulin injections; they can consult with the pharmacy team to ensure proper dosing and that there are no drug interactions that contribute to the condition. The diagnosis can be difficult to confirm clinically. Imaging studies are usually necessary. Most abdominal hematomas resolve spontaneously over 4 to 6 weeks. Nowadays, mortality rates from abdominal wall hematomas are negligible because of the availability of imaging studies. Patients who recover usually have no residual sequelae. These outcomes are made possible as described above by interprofessional teamwork and collaboration/communication, contributing to positive patient outcomes. [Level 5]