The incidence of penetrating abdominal trauma accounts for less than 10 percent of all trauma patients, with about half due to stab wounds. Stab wounds that penetrate the abdomen can be difficult to assess, leading to delay in identifying injuries and delayed complications that can add to morbidity. Injuries caused by stab wounds can be life threatening due to bleeding, auto digestion, inflammation, fluid sequestration, contamination, and peritonitis.¹ Although 50 to 70 percent of patients with abdominal stab wounds violate the peritoneum, only 25 to 33 percent of patients with abdominal stab wounds have therapeutic laparotomies, making appropriate assessments critical to treatment modalities.⁶

Definition of Regions

Stab wounds can be divided anatomically, anterior (axillary lines laterally and from costal margins to groin crease), flank and back. Anatomically, most anterior stab wounds occur in the left upper quadrant, followed by left lower quadrant, right upper and right lower.¹ The diagnostic and therapeutic approach heavily depends on the involvement of the abdominal region, with the upper limit of the abdomen defined by the diaphragm, which can rise up to the level of the nipples during exhalation.

Diagnostic Approach

A common adage in trauma is that the most missed injury is the second one. It is crucial to undress the patient so as not to miss additional injuries that may be obscured or overlooked. On physical exam, the location of stab wounds, evaluation for tenderness or signs of peritonitis, and a complete vascular exam are important.

Serial abdominal exams can be utilized to help with diagnosis of evolving injuries.^2,3 Unfortunately, physical exam alone may be difficult to determine the appropriate course of action due to confounding factors. Various imaging modalities can aid in diagnosis and drive therapeutic approaches.⁷

X-ray can be used to assess thoracoabdominal and abdominal injuries to identify, pneumothorax, hemothorax, or cardiovascular injury. X-ray can also show signs of gastric contents in the thorax or a gastric tube tracking into the chest cavity to correlate with a diaphragmatic injury. Air under the diaphragm can also be seen in the setting of bowel perforation.

Ultrasound has evolved into a dynamic tool through the extended Focused Abdominal Sonography for Trauma (eFAST) exam.^8,9 eFAST can lead to bedside interventions and identify patients with a strong predictor of injury requiring an operative repair.¹⁰

Computerized tomography (CT) scan with contrast (IV, oral, and/or rectal) is a focal point of diagnosis in trauma. Triple contrast CT scan has cited the highest accuracy, however, newer high resolution multidetector scanners with IV contrast alone are comparable in sensitivity and specificity.³ CT may also define intraperitoneal injuries that may be non-operatively managed. CT tractography, a CT scan in which contrast is injected into the stab wound, carries a high false negative rate and should not be used as the sole determinant for decision making. Delayed phase imaging for CT scans can identify collecting system injuries.² Penetrating trauma to the suprapubic region in stable patients should undergo a cystography.