An abdominal hematoma or a rectus sheath hematoma can sometimes be a cause of abdominal pain. A rectus sheath hematoma is not very common, but when it occurs, it can often be mistaken for a hernia or an abnormality of an abdominal organ. A rectus sheath hematoma usually follows an injury to the inferior or superior epigastric vessels or their branches. While this condition does resolve on its own, sometimes the hematoma can be extensive and lead to hypovolemic shock.
The hematoma results because of bleeding of the epigastric vessels or their branches in the rectus abdominis muscle sheath. Although rarely life-threatening, an abdominal hematoma can mimic many other surgical abdominal pathology. In most cases, an abdominal hematoma is self-limiting and usually spontaneously resolves. The rectus sheath hematoma can be caused after trauma to the inferior or superior epigastric vessels that run in the rectus sheath. The damage to the blood vessel may be external abdominal trauma, trauma during surgery, or intense contraction of the rectus muscles that can occur during a Valsalva maneuver, severe retching, vomiting, or straining.
The hematoma usually develops within hours following an injury. In most cases, the hematoma is localized, but in people with excessive loose connective tissue, the hematoma can spread to above the umbilicus.
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 increase.
Abdominal hematomas generally are more common on the right side, and the majority are located in the lower quadrant of the abdomen. Rectus sheath hematomas are benign and not common.
The exact number of people with a rectus sheath hematoma is not known as the condition is often misdiagnosed or not diagnosed at all. Some studies report an incidence of 1.5% to 2% in hospitalized patients.
Overall, rectus sheath hematoma is more common in females than males. The higher incidence has been linked to a decreased muscle mass. While pregnancy is a risk factor in women, in men trauma and exercise seem to the most common causes.
The rectus sheath hematoma is caused by rupture of an epigastric artery or one of its branches. The rupture may be due to blunt or penetrating trauma, surgery, or strong contractions of the rectus muscle. Since the epigastric arteries run posteriorly, making a diagnosis during a physical exam is difficult.
The lower quadrants of the abdomen are usually involved because of the long epigastric branches and lack of a tamponade effect from the loose connective tissues.
The typical presentation of a rectus sheath hematoma is that of abdominal pain, nausea, and vomiting. The pain is often sudden in onset, sharp and does not radiate. A low-grade fever may be present in some patients. 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) may be used to determine if the abdominal mass is within the abdominal wall or intra-abdominal. It is not a sensitive test 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, and use of oral anticoagulants and steroids.
Besides routine blood work and coagulation profile, ultrasound is the first test of choice to confirm the diagnosis of a rectus sheath hematoma. If ultrasound is inconclusive, CT scan is the next test and can help determine the location, size, and extension of the hematomas. In rare cases, 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.
A plain x-ray of the abdomen is not useful, but it may help rule out free air or bowel obstruction.
The treatment of rectus sheath hematoma is supportive care with pain management. Anticoagulation medications need to be discontinued. Patients with abnormal coagulation parameters may require vitamin K or fresh frozen plasma. Heparin may be reversed with protamine. Large active hematoma may be treated with gel foam embolization therapy. Surgery is usually not used to treat rectus sheath hematoma unless the hematoma is getting bigger. Patients with rectus sheath hematoma are generally treated as outpatients as long as the hemodynamic status is stable and there is no change in the hematocrit. Patients on anticoagulation therapy should be admitted to ensure that the hematoma is not expanding.
Some of these patients may need a blood transfusion.
If the bleeding persists, one may consider angiographic embolism or open surgery to ligate the blood vessel.
Even though a rectus sheath hematoma is a benign disorder, fatalities have been reported. Most of these cases have come to light during an autopsy. The mortality of a rectus sheath hematoma is higher in elderly individuals who are on oral anticoagulants. In addition, the other population at risk for mortality are pregnant women. Anecdotal 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 key reason for the morbidity and mortality in an older series was an incorrect diagnosis of abdominal pain, leading to unnecessary abdominal exploratory surgery. In other cases, the causes include a delay in reversing the anticoagulation and not transfusing blood.
Failure to make a diagnosis of a rectus sheath hematoma can lead to the following complications:
Once the patient is admitted, they should be closely monitored with serial exams, repeat blood count, and an ultrasound.
After discharge, the patient should be told not to indulge in heavy exercise. The decision to restart the oral anticoagulation requires clinical judgment.
Once a patient has been diagnosed with a rectus sheath hematoma, the surgeon should be consulted.