A 57-year-old woman with abdominal pain
WHICH IMAGING TEST WOULD BE BEST?
2. Which imaging test would be best for establishing the diagnosis in this patient?
- Plain abdominal radiography
- Abdominal ultrasonography
- Computed tomography of the abdomen and pelvis with contrast
- Magnetic resonance imaging of the abdomen and pelvis
Plain abdominal radiography
Plain abdominal radiography can help to determine if there is free gas under the diaphragm (due to bowel perforation), obstructed bowel, sentinel loop, volvulus, or fecoliths causing the abdominal pain. It cannot diagnose rectus sheath hematoma or acute mesenteric ischemia.
Abdominal ultrasonography
Abdominal ultrasonography can be used as the first diagnostic test, as it is widely available, safe, effective, and tolerable. It does not expose the patient to radiation or intravenous contrast agents. It helps to diagnose rectus sheath hematoma and helps to follow its maturation and resolution once a diagnosis is made. It can provide a rapid assessment of the size, location, extent, and physical characteristics of the mass.
Rectus sheath hematoma appears spindle-shaped on sagittal sections and ovoid on coronal sections. It often appears sonolucent in the early stages and sonodense in the late stage, but the appearance may be heterogeneous depending on the combined presence of clot and fresh blood. These findings are sufficient to make the diagnosis.
Abdominal ultrasonography has 85% to 96% sensitivity in diagnosing rectus sheath hematoma.25 It can help diagnose other causes of the abdominal pain, such as renal stones and cholecystitis. It is the preferred imaging test in pediatric patients, pregnant patients, and those with renal insufficiency.
Abdominal computed tomography
Abdominal computed tomography has a sensitivity and specificity of 100% for diagnosing acute rectus sheath hematoma with a duration of less than 5 days.25 It not only helps to determine the precise location and extent, but also helps to determine if there is active extravasation. Even in patients with renal insufficiency, noncontrast computed tomography will help to confirm the diagnosis, although it may not show extravasation or it may miss certain abdominal pathologies because of the lack of contrast.
Acute rectus sheath hematoma appears as a hyperdense mass posterior to the rectus abdominis muscle with ipsilateral anterolateral muscular enlargement. Chronic rectus sheath hematoma appears isodense or hypodense relative to the surrounding muscle. Above the arcuate line, rectus sheath hematoma has a spindle shape; below the arcuate line, it is typically spherical.
In 1996, Berná et al26 classified rectus sheath hematoma into three grades based on findings of computed tomography:
- Grade I is intramuscular and unilateral
- Grade II may involve bilateral rectus muscles without extension into the prevesicular space
- Grade III extends into the peritoneum and prevesicular space
Magnetic resonance imaging
Magnetic resonance imaging is useful to differentiate chronic rectus sheath hematoma (greater than 5-day duration) from an anterior abdominal wall mass. Chronic rectus sheath hematoma will have high signal intensity on both T1- and T2-weighted images up to 10 months after the onset of the hematoma.27
Back to our patient
Since our patient’s symptoms are acute and of less than 5 days’ duration, computed tomography of the abdomen and pelvis would be the best diagnostic test, with therapeutic implications if there is ongoing extravasation.
Computed tomography of the abdomen with contrast showed a new hematoma, measuring 25 by 14 by 13.5 cm, in the right rectus sheath (Figure 2), with no other findings. The hematoma was grade I, since it was intramuscular and unilateral without extension elsewhere.
Laboratory workup showed that the patient’s hematocrit was falling, from 34% to 24%, and her INR was elevated at 2.5. She was resuscitated with fluids, blood transfusion, and fresh-frozen plasma. Anticoagulation was withheld. In spite of resuscitation, her hematocrit kept falling, though she remained hemodynamically stable.
THE WAY FORWARD
3. At this point, what would be the best approach to management in this patient?
- Serial clinical examinations and frequent monitoring of the complete blood cell count
- Urgent surgical consult for exploratory laparotomy with evaluation of the hematoma and ligation of the bleeding vessel
- Repeat computed tomographic angiography to identify a possible bleeding vessel; consideration of radiographically guided arterial embolization
- Measuring the intra-abdominal pressure using the intrabladder pressure for abdominal compartment syndrome and consideration of surgical drainage
The key clinical concern in a patient with a rectus sheath hematoma who is hemodynamically stable is whether the hematoma is expanding. This patient responded to initial resuscitation, but her falling hematocrit was evidence of ongoing bleeding leading to an expanding rectus sheath hematoma. Thus, serial clinical examinations and frequent monitoring of the complete blood cell count would not be enough, as it could miss fatal ongoing bleeding.
Radiographically guided embolization with Gelfoam, thrombin, or coils should be attempted first, as this is less invasive than exploratory laparotomy.28 It can achieve hemostasis, decrease the size of the hematoma, limit the need for blood products, and prevent rupture into the abdomen. If this is unsuccessful, the next step is ligation of the bleeding vessel.29
Surgical treatment includes evacuation of the hematoma, repair of the rectus sheath, ligation of bleeding vessels, and abdominal wall closure. Surgical evacuation or guided drainage of a rectus sheath hematoma on its own is not normally indicated and may indeed cause persistent bleeding by diminishing a potential tamponade effect. However, it may become necessary if the hematoma is very large or infected, if it causes marked respiratory impairment, or if abdominal compartment syndrome is suspected.
Abdominal compartment syndrome is very rare but is associated with a 50% mortality rate.30 It should be suspected in patients with oliguria, low cardiac output, changes in minute ventilation, and altered splanchnic blood flow. The diagnosis is confirmed with indwelling catheter manometry of the bladder to measure intra-abdominal pressure. Intra-abominal pressure above 25 mm Hg should be treated with decompressive laparotomy.30 However, the clinical suspicion of abdominal compartment syndrome was low in this patient.
The best choice at this point would be urgent computed tomographic angiography to identify a bleeding vessel, along with consideration of radiographically guided arterial embolization.
TREATMENT IS USUALLY CONSERVATIVE
Treatment of rectus sheath hematoma is conservative in most hemodynamically stable patients, with embolization or surgical intervention reserved for unstable patients or those in whom the hematoma is expanding.
Knowledge of the grading system of Berná et al26 helps to assess the patient’s risk and to anticipate potential complications. Grade I hematomas are mild and do not necessitate admission. Patients with grade II hematoma can be admitted to the floor for 24 to 48 hours for observation. Grade III usually occurs in patients receiving anticoagulant therapy and frequently requires blood products. These patients have a prolonged hospital stay and more complications, including hypovolemic shock, myonecrosis, acute coronary syndrome, arrhythmias, acute renal failure, small-bowel infarction, and abdominal compartment syndrome—all of which increases the risk of morbidity and death. Thus, patients who are on anticoagulation who develop grade III rectus sheath hematoma should be admitted to the hospital, preferably to the intensive care unit, to ensure that the hematoma is not expanding and to plan reinstitution of anticoagulation as appropriate.
In most cases, rectus sheath hematomas resolve within 1 to 3 months. Resolution of large hematomas may be hastened with the use of pulsed ultrasound.31 However, this treatment should be used only after the acute phase is over, when there is evidence of an organized thrombus and coagulation measures have returned to the target range. This helps to reduce the risk of bleeding and to prevent symptoms from worsening.31
OUR PATIENT’S COURSE
Our patient underwent urgent computed tomographic angiography, which showed a modest increase in the size of the rectus sheath hematoma. However, no definitive blush of contrast was seen to suggest active arterial bleeding. Her hematocrit stabilized, and she remained hemodynamically stable without requiring additional intervention. Most likely her bleeding was self-contained. She had normal intra-abdominal pressure on serial monitoring. She was later transferred to acute inpatient rehabilitation in view of deconditioning and is currently doing well. The hematoma persisted, decreasing only slightly in size over the next 3 weeks.
