A 28-year-old man is brought to the trauma bay following a stab wound to the left flank. He is in hemorrhagic shock (BP 78/48, HR 135, RR 32, pale and diaphoretic). Focused abdominal sonography for trauma (FAST) shows free fluid in the peritoneal cavity. Which is the most common source of hemorrhage in penetrating abdominal trauma?
A. Small bowel and mesentery
B. Stomach
C. Colon and rectum
D. Liver
Explanation
Most Common Bleeding Source in Penetrating Abdominal Trauma
Key Point
The small bowel and its mesentery are the most frequently injured structures in penetrating abdominal trauma (stab wounds and gunshot wounds), accounting for 30–50% of injuries and being the leading source of hemorrhage in this setting.
Epidemiology of Penetrating Abdominal Injuries
Table
Structure
Frequency (%)
Hemorrhage Risk
Mortality
Small bowel + mesentery
30–50
High (mesenteric vessels)
5–10%
Liver
20–40
Very high
10–15%
Colon
15–25
Moderate (perforation > bleeding)
3–5%
Stomach
10–20
Low–moderate
2–4%
Spleen
10–15
High
5–8%
High-YieldNEET PG
In penetrating trauma, the small bowel is injured more often than any other organ because:
1.
It occupies the largest surface area in the abdomen
2.
It is highly mobile and exposed to direct laceration
Most stab wounds follow a linear trajectory through bowel loops
Why Small Bowel Bleeds Are Most Common in Penetrating Trauma
1.
Anatomical exposure — small bowel loops fill most of the peritoneal cavity
2.
Mesenteric vasculature — superior mesenteric artery (SMA) and vein run through the mesentery; injury causes massive hemorrhage
3.
Mechanism — stab wounds create linear lacerations through multiple bowel loops
4.
Contrast with blunt trauma — in blunt trauma, solid organs (liver, spleen) are injured; in penetrating trauma, hollow viscera and vessels are at risk
Clinical Pearl
Penetrating vs. Blunt Trauma:
Blunt: Liver and spleen are most common (solid organ injury)
Penetrating: Small bowel and mesentery are most common (hollow viscus + vascular injury)
The presence of free fluid on FAST in a hemodynamically unstable patient with penetrating trauma is an indication for immediate exploratory laparotomy — do not delay for CT imaging.
Mnemonic: SBM BLEEDS — Small Bowel and Mesentery are the most common sources of hemorrhage in penetrating trauma.
ATLS 10th Edition, Chapter 5: Abdominal and Pelvic Trauma
Practice similar questions
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.
