A 35-year-old man presents with blunt abdominal trauma from a motor vehicle collision. On examination, he is haemodynamically unstable (BP 90/60 mmHg, HR 130/min) despite 2 litres of crystalloid infusion. FAST scan shows free fluid in the peritoneal cavity. Which of the following is the MOST likely source of bleeding in blunt abdominal trauma?

Explanation

## Haemodynamic Instability in Blunt Abdominal Trauma ### Epidemiology of Bleeding Sources: In blunt abdominal trauma with haemodynamic instability and free intra-abdominal fluid: | Organ | Frequency | Severity | |-------|-----------|----------| | **Spleen** | 40–50% | High (Grade III–V common) | | **Liver** | 30–40% | Variable (often Grade II–III) | | **Mesentery/Bowel** | 10–15% | Variable | | **Pancreas** | <5% | Usually Grade I–II | ### Why Splenic Injury is Most Common: 1. **Anatomical position:** Anterolateral, mobile, easily injured by blunt force 2. **Vascular supply:** Splenic artery is terminal (no collaterals); lacerations bleed profusely 3. **Friability:** Splenic parenchyma is soft and easily damaged 4. **High-grade injuries:** Splenic injuries frequently present as Grade III–V with massive bleeding ### Clinical Presentation: - **Haemodynamic instability** is more common with splenic injury than isolated liver injury - Free fluid on FAST is typical - Left upper quadrant tenderness (Kehr sign: left shoulder pain) **High-Yield Fact:** The spleen accounts for >40% of bleeding deaths in blunt abdominal trauma, making it the most common source of life-threatening haemorrhage.