A 32-year-old man is brought to the emergency department following a motor vehicle collision with blunt abdominal trauma. On FAST examination, free fluid is detected in the pelvis. Which organ is the most common source of intra-abdominal bleeding in blunt abdominal trauma?

Explanation

## Most Common Source of Bleeding in Blunt Abdominal Trauma **Key Point:** The spleen is the most frequently injured solid organ in blunt abdominal trauma, accounting for approximately 40–50% of all solid organ injuries. ### Anatomical Basis - The spleen is highly vascular with a fragile capsule and no peritoneal covering on its lateral surface - It is relatively mobile and unprotected by the rib cage compared to the liver - Deceleration injuries cause shearing forces that tear the splenic parenchyma ### Clinical Significance - Splenic injury ranges from Grade I (minor laceration) to Grade V (complete devascularization) - Most splenic injuries (80–90%) can be managed non-operatively with bed rest and serial clinical examination in haemodynamically stable patients - Operative intervention (splenectomy) is reserved for Grade IV–V injuries or haemodynamic instability **High-Yield:** FAST examination detects free fluid in the splenorenal recess (left upper quadrant) as a marker of splenic bleeding. ### Comparison of Solid Organ Injuries | Organ | Frequency | Haemodynamic Stability | Management | |-------|-----------|------------------------|-------------| | Spleen | 40–50% | Often stable | Non-operative (Grade I–III) | | Liver | 35–40% | Often unstable | Operative if Grade IV–V | | Kidney | 10–15% | Usually stable | Conservative | | Pancreas | <5% | Rare isolated | Operative if ductal injury | **Clinical Pearl:** A patient with splenic injury who remains haemodynamically stable after aggressive fluid resuscitation can be managed expectantly, avoiding unnecessary splenectomy and preserving immunological function. [cite:ATLS 10th Edition]