Abdominal Trauma
Surgery · Trauma · lean revision notes
Abdominal Trauma
Abdominal trauma is a leading cause of preventable death in the polytrauma patient, chiefly through unrecognised haemorrhage and delayed recognition of hollow-viscus injury. The examination focus is the decision algorithm: who goes straight to theatre, who gets a CT, and who is observed (non-operative management). Master the AAST grading, FAST vs DPL vs CT, and damage-control principles.
Definition & Classification
Abdominal trauma is any injury to the structures within the abdominal cavity (peritoneal and retroperitoneal) and pelvis. It is broadly split by mechanism:
| Feature | Blunt trauma | Penetrating trauma |
|---|---|---|
| Common cause (India) | Road traffic accident, fall, assault | Stab, gunshot, impalement |
| Most injured organ | Spleen (most common solid organ) | Small bowel (stab); small bowel/colon/liver (gunshot) |
| Mechanism of damage | Compression, deceleration, burst | Laceration along tract, blast/cavitation (high-velocity) |
| Diagnosis difficulty | High (occult injury common) | Often clearer; tract may be traced |
| Default management | Often non-operative if stable | Lower threshold for laparotomy |
Anatomically the abdomen is divided into:
- Intrathoracic abdomen – under the diaphragm/lower ribs (liver, spleen, stomach); rib fractures suggest injury here.
- True (intraperitoneal) abdomen – small bowel, transverse colon, intraperitoneal bladder.
- Pelvic abdomen – rectum, bladder, iliac vessels, female reproductive organs.
- Retroperitoneum – pancreas, duodenum, kidneys, ureters, aorta, IVC; injuries here are notoriously missed because they evade peritoneal signs and FAST.
High-yield: The spleen is the most commonly injured organ in blunt abdominal trauma; the small bowel is the commonest in penetrating (stab) trauma. The liver is the commonest cause of fatal haemorrhage and the most injured organ in some gunshot series.
Etiology & Pathophysiology
Solid organs (spleen, liver, kidney) bleed; hollow organs (bowel, bladder) leak and cause peritonitis/sepsis. The clinical consequence and timing differ markedly.
- Deceleration injuries tear organs at points of fixation: liver at the ligamentum teres, small bowel at the ligament of Treitz and ileocaecal junction, aorta at the ligamentum arteriosum (thoracic), and mesentery (bucket-handle tear).
- Compression/crush against the vertebral column injures the pancreas and duodenum (classic handlebar injury in children, seat-belt mechanism).
- Seat-belt sign (linear ecchymosis across the abdomen) is associated with hollow viscus (small bowel) injury, mesenteric tear, and Chance fracture of the lumbar spine.
High-yield: The seat-belt sign + Chance fracture (flexion-distraction L1–L3 fracture) triad should raise strong suspicion of small bowel/mesenteric injury even if initial imaging is unremarkable.
Pathophysiology of shock: solid-organ laceration → haemoperitoneum → hypovolaemic (haemorrhagic) shock. Hollow-viscus perforation → chemical then bacterial peritonitis → septic shock if delayed.
Clinical Features
- Haemorrhagic shock: tachycardia, hypotension, narrowed pulse pressure, cool clammy skin, altered sensorium. Hypotension is a late sign in young patients (compensate up to ~30% blood loss).
- Peritoneal signs: guarding, rigidity, rebound tenderness, absent bowel sounds — suggest hollow-viscus injury or significant haemoperitoneum.
- Specific signs:
- Kehr's sign – left shoulder-tip pain from diaphragmatic irritation by splenic blood (classic for splenic injury).
- Cullen's sign (periumbilical bruising) and Grey-Turner's sign (flank bruising) – retroperitoneal/intraperitoneal haemorrhage (also pancreatitis).
- Balance's sign – fixed dullness in the left flank (perisplenic clot), shifting dullness on the right (free blood) in splenic rupture.
- Be aware: physical examination is unreliable in the intoxicated, head-injured, intubated, or spinal-cord-injured patient — lower your imaging threshold.
Diagnosis & Investigation of Choice
The pivotal first decision is haemodynamic status, not the imaging itself.
Stepwise approach (ATLS):
- Primary survey (ABCDE) → identify and treat immediately life-threatening problems; 2 large-bore IV cannulae, resuscitate.
- Assess haemodynamics → stable vs unstable (transient/non-responder to fluid).
- Unstable patient → bedside FAST (or DPL if FAST unavailable). FAST positive + unstable → straight to laparotomy. FAST negative + unstable → look for extra-abdominal bleeding (chest, pelvis, long bones, "blood on the floor").
- Stable patient → CT abdomen-pelvis with IV contrast is the investigation of choice.
The flow in one line: Unstable + FAST(+) → OT → ; Unstable + FAST(–) → seek other source / DPL → ; Stable → CECT → ; Penetrating with peritonitis/evisceration/hypotension → laparotomy.
FAST vs DPL vs CT
| Parameter | FAST | DPL | CT abdomen (CECT) |
|---|---|---|---|
| What it detects | Free fluid (≥200 mL) in Morrison's pouch, perisplenic, pelvis, pericardium | Intraperitoneal blood/enteric content | Organ injury, grade, active extravasation, retroperitoneum |
| Speed | Fastest, bedside, repeatable | Fast, invasive | Slower; needs transport |
| Best use | Unstable patient triage | Unstable when FAST unavailable/equivocal | Stable patient, definitive |
| Sensitivity for hollow viscus | Poor | Good (WBC, enteric content) | Moderate (free fluid without solid injury = suspect bowel) |
| Retroperitoneum | Cannot assess | Cannot assess | Best |
| Limitation | Operator-dependent; misses retroperitoneum, hollow viscus, diaphragm; obscured by gas/obesity | Invasive, over-sensitive (non-therapeutic laparotomy), can't grade | Radiation, contrast, needs stable patient |
High-yield: FAST views (4): Right upper quadrant (Morrison's hepatorenal pouch — most sensitive/dependent), Left upper quadrant (perisplenic), Pelvis (pouch of Douglas/rectovesical), Pericardial (subxiphoid). e-FAST adds bilateral thoracic windows for pneumothorax/haemothorax.
DPL positivity criteria (classic, still examined)
A DPL is positive if aspiration yields:
- ≥10 mL gross blood on initial aspiration, OR
- RBC count ≥100,000/mm³ (blunt), OR
- WBC ≥500/mm³, OR
- Presence of bile, bacteria, food fibres, or amylase, OR
- Lavage fluid exiting via chest drain / Foley catheter.
DPL is the most sensitive test for haemoperitoneum but has been largely replaced by FAST (non-invasive) and CT (specific, grades injury). It retains a role where FAST is equivocal in the unstable patient.
High-yield: Free fluid on CT without a solid-organ injury strongly suggests a hollow-viscus or mesenteric injury — do not ignore it; consider laparotomy/laparoscopy.
AAST Organ Injury Grading
The American Association for the Surgery of Trauma (AAST) scale grades I (least) to V/VI (most severe). It guides non-operative management (NOM) and predicts angioembolisation need.
Spleen (AAST splenic injury scale)
| Grade | Findings |
|---|---|
| I | Subcapsular haematoma <10% surface area; capsular tear <1 cm deep |
| II | Subcapsular haematoma 10–50%; intraparenchymal <5 cm; laceration 1–3 cm not involving trabecular vessels |
| III | Subcapsular >50% or expanding/ruptured; intraparenchymal ≥5 cm; laceration >3 cm or involving trabecular vessels |
| IV | Laceration involving segmental or hilar vessels → >25% devascularisation |
| V | Shattered spleen or hilar vascular injury devascularising the whole spleen |
The 2018 AAST update adds vascular injury (pseudoaneurysm, active bleed) which upstages to grade IV/V regardless of the parenchymal picture.
Liver (AAST hepatic injury scale, summarised)
| Grade | Findings |
|---|---|
| I | Subcapsular haematoma <10%; laceration <1 cm deep |
| II | Subcapsular 10–50%; laceration 1–3 cm deep, <10 cm long |
| III | Subcapsular >50%/ruptured; laceration >3 cm deep |
| IV | Parenchymal disruption involving 25–75% of a hepatic lobe |
| V | Disruption >75% of a lobe; juxtahepatic venous injury (retrohepatic IVC, central major hepatic veins) |
| VI | Hepatic avulsion (incompatible with survival) |
High-yield: Grade alone does not dictate surgery — haemodynamic status does. A high-grade splenic/liver injury in a stable patient can still be managed non-operatively in a monitored setting, often with angioembolisation for a contrast blush/pseudoaneurysm.
Management & Drug/Procedure of Choice
Non-operative management (NOM)
NOM is the standard of care for blunt solid-organ injury when criteria are met:
- Haemodynamic stability (responds to/maintains after resuscitation) — the single most important criterion.
- No peritonitis (no signs mandating laparotomy).
- Facilities for serial abdominal examination, monitoring (ICU/HDU), repeat imaging, and immediate operative backup.
- Limited transfusion requirement (classically failure if needing >2–4 units attributable to the abdominal injury).
- Angioembolisation available for contrast blush/active arterial extravasation/pseudoaneurysm — extends NOM success in high-grade spleen and liver injuries.
NOM success is highest for liver injuries; the spleen has somewhat higher failure rates with rising grade. Delayed splenic rupture is a recognised pitfall.
Indications for immediate laparotomy
Memorise these — they are repeatedly tested:
- Haemodynamic instability with positive FAST/DPL (peritoneal source).
- Peritonitis (generalised).
- Evisceration of bowel/omentum.
- Free air / pneumoperitoneum or diaphragmatic injury.
- Blood from NG tube, rectum, or genitourinary tract with imaging concern.
- Gunshot wound traversing the peritoneal cavity (most go to laparotomy).
- Impalement / retained weapon (remove only in theatre).
- CT-confirmed injury needing repair (e.g., pancreatic ductal, hollow viscus).
High-yield: Penetrating trauma — anterior abdominal stab wounds in a stable patient without peritonitis may be selectively managed (local wound exploration / serial exam / CT / laparoscopy). Gunshot wounds that breach the peritoneum almost always require laparotomy.
Splenic surgery
- Splenorrhaphy / partial splenectomy preferred in stable patients (preserve splenic function), especially children.
- Splenectomy for shattered spleen, hilar injury, or instability.
- Post-splenectomy vaccination against encapsulated organisms — pneumococcus, meningococcus, Haemophilus influenzae type b — to prevent OPSI (overwhelming post-splenectomy infection), plus penicillin prophylaxis in children. Ideally vaccinate ~2 weeks post-op (or at discharge in trauma).
Liver surgery
- Perihepatic packing is the cornerstone of damage control.
- Pringle manoeuvre – occlude the portal triad (hepatic artery + portal vein) at the hepatoduodenal ligament (foramen of Winslow) to control bleeding; continued bleeding despite a Pringle = retrohepatic IVC or hepatic vein injury.
- Angioembolisation for arterial bleeding; atriocaval (Schrock) shunt for juxtahepatic venous injury (high mortality).
Damage-control laparotomy (DCL)
For the exsanguinating/physiologically exhausted patient. The triad driving it is the "lethal/bloody triad": hypothermia + acidosis + coagulopathy.
Three stages:
- Abbreviated laparotomy – control haemorrhage (packing) and contamination (staple/ligate bowel, no anastomosis); temporary abdominal closure (e.g., vac/Bogota bag).
- ICU resuscitation – rewarm, correct coagulopathy and acidosis, "permissive hypotension" until bleeding controlled.
- Planned re-laparotomy at 24–48 h – definitive repair, anastomoses, fascial closure.
High-yield: Damage control surgery is indicated by physiology, not anatomy — temperature <35°C, pH <7.2, INR/coagulopathy, base deficit, persistent transfusion requirement.
Adjuncts
- Massive transfusion protocol in balanced ratio 1:1:1 (packed cells : FFP : platelets).
- Tranexamic acid within 3 hours (CRASH-2 evidence) reduces death from bleeding.
- REBOA (resuscitative endovascular balloon occlusion of the aorta) as a bridge in select non-compressible torso/pelvic haemorrhage.
Complications
- Early: haemorrhage/rebleed, missed hollow-viscus injury, peritonitis, abdominal compartment syndrome (bladder pressure >20 mmHg with new organ dysfunction → decompressive laparotomy).
- Pancreatic: pseudocyst, fistula, pancreatitis (especially missed ductal injury).
- Hepatic: biloma, bile leak, haemobilia (triad of jaundice, GI bleed, RUQ pain), hepatic abscess.
- Splenic: delayed rupture, splenosis, OPSI (lifelong risk).
- Delayed: intra-abdominal abscess, adhesive obstruction, incisional hernia, post-traumatic diaphragmatic hernia (often left, presents late).
Key Differentials & Pitfalls
- Retroperitoneal injuries (pancreas, duodenum, kidney) — FAST/DPL negative; rely on CT and a high index of suspicion. Rising serum amylase/lipase or duodenal wall thickening/retroperitoneal air = duodenal/pancreatic injury.
- Diaphragmatic rupture — missed on FAST; suspect with left-sided injury, NG tube in chest on X-ray; needs CT/laparoscopy.
- Pelvic fracture bleeding — may cause a positive FAST from associated visceral injury but the bleed is often retroperitoneal/venous → pelvic binder + angioembolisation/preperitoneal packing, not necessarily laparotomy.
- Mesenteric/bowel injury — free fluid without solid-organ injury; seat-belt sign; delayed presentation.
Recently asked / exam angle
- Most commonly injured organ: spleen (blunt), small bowel (penetrating/stab) — perennial single-best-answer.
- Investigation of choice: FAST in the unstable patient, CECT in the stable patient — distinguish these in the stem by haemodynamics.
- DPL positivity numbers: ≥10 mL gross blood, RBC ≥1,00,000/mm³ — frequently tested as numerical cut-offs.
- Kehr's sign → splenic injury (left shoulder pain); Balance's sign; Grey-Turner/Cullen matched to retroperitoneal bleed.
- Pringle manoeuvre — what it occludes (portal triad) and that ongoing bleeding implies retrohepatic IVC/hepatic vein injury.
- Damage control surgery stages and the lethal triad (hypothermia, acidosis, coagulopathy).
- Indications for laparotomy in penetrating trauma (evisceration, peritonitis, instability, gunshot crossing peritoneum).
- OPSI prophylaxis after splenectomy (three encapsulated organisms).
- Seat-belt sign + Chance fracture → small-bowel/mesenteric injury.
- Abdominal compartment syndrome bladder pressure cut-off (>20 mmHg with organ dysfunction).
Mnemonic — organs that bleed vs leak: "Solid organs Spill blood, Hollow organs Leak content." And for FAST positivity dependent area: Morrison's pouch is the most dependent space in the supine patient → earliest free fluid.
Mnemonic — laparotomy indications (penetrating): "GIPED" – Gunshot crossing peritoneum, Impalement, Peritonitis, Evisceration, Destabilised haemodynamics.
Rapid revision
- Spleen = most commonly injured in blunt trauma; small bowel = most common in penetrating (stab).
- Unstable + FAST positive → straight to laparotomy; stable patient → CECT is investigation of choice.
- FAST detects free fluid (≥200 mL); Morrison's pouch is the most sensitive window; misses retroperitoneum, hollow viscus, diaphragm.
- DPL positive: ≥10 mL gross blood OR RBC ≥1,00,000/mm³ OR bile/bacteria/food fibres.
- Free fluid on CT without solid-organ injury = suspect hollow-viscus/mesenteric injury.
- NOM depends on haemodynamic stability, not the AAST grade; angioembolisation extends NOM success.
- AAST grade V spleen = shattered/hilar devascularisation; grade VI liver = avulsion (lethal).
- Kehr's sign (left shoulder pain) = splenic injury; Pringle manoeuvre occludes the portal triad.
- Bleeding despite Pringle = retrohepatic IVC / hepatic vein injury.
- Damage-control surgery is dictated by physiology — the lethal triad: hypothermia, acidosis, coagulopathy; transfuse 1:1:1 and give tranexamic acid <3 h.
- Post-splenectomy → vaccinate against pneumococcus, meningococcus, Hib to prevent OPSI.
- Seat-belt sign + Chance fracture → small-bowel/mesenteric injury; bladder pressure >20 mmHg + organ dysfunction = abdominal compartment syndrome needing decompression.