Rectus sheath hematoma (RSH) is an uncommon and often clinically misdiagnosed cause of abdominal pain. It is the result of bleeding into the rectus sheath from damage to the superior or inferior epigastric arteries or their branches or from a direct tear of the rectus muscle,
- Anticoagulation: Rectus sheath hematoma is a well-recognized complication of anticoagulant therapy
- Coughing: Rectus sheath hematoma can occur after bouts of severe coughing, explaining its association with asthma, tuberculosis, influenza, pertussis, and other respiratory infections.
- Pregnancy: Rectus sheath hematoma is associated with pregnancy in the gravid state, during labor, and in the early postpartum period.
- Previous abdominal surgery: Abdominal operations predispose to rectus sheath hematoma because surgical scars redirect the shearing forces on muscle contraction, placing more stress on the epigastric vessels.
- Recent abdominal surgery: Excessive retraction or inadequate hemostasis can cause rectus sheath hematoma that may become evident up to 4 weeks after the procedure.
- External trauma: The nature of the trauma can be trivial. Tight contraction of the recti in anticipation of a blow predisposes. to rectus sheath hematoma formation
- Vigorous uncoordinated rectus muscle contraction: Rectus sheath hematoma has been observed in a healthy man leaping over a ditch and in a woman rising from a chair to adjust a curtain rod. In a similar manner, sports activities, such as golf, tennis, skiing, and weightlifting, have caused rectus sheath hematoma. Activities with significant Valsalva effort, such as coughing, sneezing, straining from constipation, urination, and sexual intercourse, have been implicated in rectus sheath hematoma
Ultrasonography: Ultrasonography can be used as a first-line diagnostic test for rectus sheath hematoma, or it can be used to monitor the evolution of a known hematoma. Ultrasonography provides rapid accurate information about the size, the location, and the physical characteristics of the mass,
Expected findings: Rectus sheath hematomas are described as spindle shaped on sagittal sections and as ovoid on coronal sections. Usually, the mass is sonolucent, although it may also be heterogenous, depending on the combined presence of clot and fresh blood
CT:Expected findings: Characteristic findings of acute rectus sheath hematoma on CT include a hyperdense mass posterior to the rectus abdominis muscle with ipsilateral anterolateral muscular enlargement. Chronic rectus sheath hematoma may be isodense or hypodense relative to the surrounding muscle. Above the arcuate line, rectus sheath hematomas have a spindle shape, while those below the arcuate line are typically spherical
Types of rectus sheath hematoma on CT scanning: In 1996, Berna used the appearance of rectus sheath hematomas on CT scans to differentiate 3 levels of severity with disposition and therapeutic implications.2
- Type I: The hematoma is intramuscular, and an increase in the size of the muscle is observed, with an ovoid or fusiform aspect and hyperdense foci or a diffusely increased density. The hematoma is unilateral and does not dissect along the fascial planes.
- Type II: The hematoma is intramuscular (mimicking type I) but with blood between the muscle and the transversalis fascia. It may be unilateral or bilateral, and no blood is observed occupying the prevesical space. A fall in hematocrit may be observed.
- Type III: The hematoma may or may not affect the muscle, and blood is observed between the transversalis fascia and the muscle, in the peritoneum, and in the prevesical space. A hematocrit effect can be observed, and on occasion, hemoperitoneum is produced.