Abdominal Injuries

Introduction

Abdominal trauma is a significant cause of morbidity and mortality in Canada, often resulting from motor vehicle collisions (MVCs), falls, and interpersonal violence. For the MCCQE1, understanding the triage, assessment, and management of these injuries is paramount.

The approach to abdominal injuries is deeply rooted in the CanMEDS roles, specifically Medical Expert (clinical decision making) and Collaborator (trauma team dynamics).

Classification of Injury

Initial Assessment and Management

The management of abdominal trauma follows the Advanced Trauma Life Support (ATLS) guidelines, which is the standard of care in Canadian Emergency Departments.

Diagnostic Investigations

The choice of investigation depends entirely on the patient’s hemodynamic status.

1. FAST (Focused Assessment with Sonography for Trauma)

• Indication: Unstable blunt trauma patients.
• Views: Pericardial, Perihepatic (Morison’s pouch), Perisplenic, Pelvic.
• MCCQE1 Pearl: A positive FAST in an unstable patient is an indication for immediate laparotomy.

2. CT Abdomen/Pelvis (with IV contrast)

• Indication: Hemodynamically STABLE patients.
• Benefit: Gold standard for diagnosis. Visualizes solid organs, retroperitoneum, and bony structures.
• Limitation: Poor sensitivity for hollow viscus (bowel) and diaphragmatic injuries.

3. Diagnostic Peritoneal Lavage (DPL)

• Status: Largely historical in Canadian centres with ultrasound/CT availability but still testable.
• Indication: Unstable patient with equivocal FAST or no ultrasound available.
• Positive criteria: >10 mL gross blood, RBC count >100,000/mm³, WBC >500/mm³, presence of bile/bacteria/food.

Comparison of Diagnostic Modalities

Specific Organ Injuries

Spleen

• Mechanism: Blunt trauma (LUQ impact). Associated with left lower rib fractures.
• Signs: LUQ pain, Kehr’s Sign (referred pain to left shoulder due to diaphragmatic irritation).
• Management:
  • Stable: Non-Operative Management (NOM) with close monitoring/serial Hgb. Angioembolization if contrast blush on CT.
  • Unstable: Splenectomy or Splenorrhaphy.
• Post-Splenectomy: Patients require vaccination against encapsulated organisms (Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae) typically 14 days post-op or pre-discharge.

Liver

• Mechanism: Blunt (RUQ) or penetrating.
• Management:
  • Stable: NOM is successful in >80% of cases.
  • Unstable: Operative.
  • Pringle Maneuver: Clamping the hepatoduodenal ligament (portal vein, hepatic artery, common bile duct) to control bleeding. If bleeding continues, the source is likely the Hepatic Veins or IVC.

Bowel (Hollow Viscus)

• Mechanism: Deceleration injury (bucket-handle tear) or seatbelt injury.
• Signs: Seatbelt Sign (ecchymosis across the abdomen).
• Diagnosis: Difficult on CT. Look for free air or free fluid without solid organ injury.
• Management: Operative repair (resection/anastomosis).

Retroperitoneal Injuries

Structures in the retroperitoneum are often missed by FAST.

// Mnemonic: SAD PUCKER
S = Suprarenal (Adrenal) glands
A = Aorta/IVC
D = Duodenum (2nd and 3rd part)
 
P = Pancreas (except tail)
U = Ureters
C = Colon (ascending and descending)
K = Kidneys
E = Esophagus
R = Rectum

Canadian Guidelines & Clinical Decision Rules

Indications for Immediate Laparotomy

In the Canadian context, surgical exploration is indicated for:

1. Unstable blunt trauma with positive FAST or DPL.
2. Unstable penetrating trauma.
3. Gunshot wounds traversing the peritoneal cavity.
4. Evisceration.
5. Free air on X-ray or CT.
6. Diaphragmatic rupture.
7. Peritonitis on physical exam.

Non-Operative Management (NOM)

Modern trauma care in Canada emphasizes organ preservation. NOM is the standard for hemodynamically stable solid organ injuries (Liver, Spleen, Kidney), provided the facility has:

• Continuous hemodynamic monitoring capabilities.
• Immediate availability of a surgeon and OR.
• Access to angiography/interventional radiology.

Key Points to Remember for MCCQE1

• Hypotension in a trauma patient is caused by hemorrhage until proven otherwise.
• Pelvic Binders should be applied at the level of the greater trochanters for suspected pelvic fractures in unstable patients.
• Urethral Injury: Do not insert a Foley catheter if there is blood at the meatus, scrotal hematoma, or high-riding prostate. Perform a retrograde urethrogram first.
• Diaphragmatic Rupture: More common on the left side (liver protects the right). Diagnosed via CT or laparoscopy.
• Chance Fracture: Horizontal fracture through a vertebra, associated with seatbelt injuries and high risk of bowel injury.

Sample Question

Explanation

The correct answer is:

• C. Immediate exploratory laparotomy

Detailed Analysis:

This is a classic MCCQE1 trauma scenario testing your ability to apply the algorithm for blunt abdominal trauma based on hemodynamic stability.

1. Patient Status: The patient is hemodynamically unstable (Hypotensive: BP 85/50, Tachycardic: HR 135). This indicates Class III/IV shock.
2. Investigation: The FAST scan is positive (free fluid).
3. Synthesis: Unstable patient + Positive FAST = Immediate Laparotomy. There is massive internal hemorrhage that requires surgical control.

Why other options are incorrect:

• A. CT Scan: CT is the gold standard for stable patients. Sending an unstable patient to the CT scanner (“tunnel of death”) is unsafe practice.
• B. DPL: DPL is indicated for unstable patients with an equivocal or negative FAST where clinical suspicion remains high. Since the FAST is positive, DPL adds no value and delays definitive care.
• D. Angiography: While angioembolization is used for splenic injuries, it is generally reserved for stable patients with active extravasation on CT, or as an adjunct. It is not the primary step for an unstable patient with hemoperitoneum.
• E. Crystalloid/Observation: While initial resuscitation involves fluids/blood, “observing for response” in a hypotensive patient with confirmed hemoperitoneum is negligent. He needs hemorrhage control. Furthermore, current guidelines limit crystalloid use in favor of blood products (damage control resuscitation).

References

1. American College of Surgeons. (2018). ATLS: Advanced Trauma Life Support Student Course Manual (10th ed.). Chicago, IL: American College of Surgeons.
2. Dunn, J., et al. (2023). Trauma Management Guidelines. Canadian Journal of Surgery.
3. Medical Council of Canada. (2023). MCCQE Part I Objectives: Trauma.
4. Ball, C. G., et al. (2010). The nonoperative management of blunt splenic trauma: A Canadian perspective. Canadian Journal of Surgery, 53(2).
5. Public Health Agency of Canada. Canadian Immunization Guide: Part 3 - Vaccination of Specific Populations (Asplenia).