Abdominal Trauma, Imaging

Basics

Description

Diagnostic procedures: Use of these imaging and procedure modalities will be based on history and physical exam.

Diagnosis

Signs and Symptoms

  • Abdominal trauma can be seen in a variety of patients ranging from those with isolated abdominal injury to multisystem trauma.
  • Abdominal trauma is divided into blunt and penetrating injuries. Penetrating abdominal injuries can further be divided into stab wounds and gunshot wounds.
  • Hemodynamic status should be the primary initial focus of evaluation. Most unstable patients will require early surgical management, while many stable patients with abdominal trauma may be managed nonoperatively.

History
  • History should include mechanism of injury, restraint use and type, airbag or helmet use, prehospital vital signs, initial mental status, and change in mental status.
  • AMPLE history (allergies-to-medications and radiographic contrast agents, medications taken, past medical and surgical history, last meal, events leading up to the injury)

Physical Exam
  • A comprehensive physical exam should start with ABCDE survey and include full exposure of the patient and careful palpation of all abdominal quadrants.
  • Abdominal injury in only 45–50% of cases.
  • The abdominal physical exam is frequently misleading in intoxicated, uncooperative, and multisystem trauma patients.

Essential Workup

  • See “Abdominal Trauma (Blunt)” and “Abdominal Trauma (Penetrating).”
  • All trauma patients initially managed with:
    • ABCDE survey (Airway, Breathing, Circulation, Disability, Exposure)

Diagnostic Tests and Interpretation

General approach to imaging in abdominal trauma:
  • Unstable trauma patients:
    • Unstable patients should have a bedside ultrasound performed immediately as part of the primary survey (circulation). A positive FAST suggests that intra-abdominal bleeding is the source of hypotension. A negative FAST suggests either a retroperitoneal bleed, blood loss in the field, bleeding from an unstable pelvic fracture, or hemorrhage into another body cavity.
    • A surgeon should be consulted immediately to prepare for definitive operative care of the patient.
    • Stable trauma patients: The 3 main modes of diagnosing the extent of injury in hemodynamically stable abdominal trauma patients include:
      • US: Initial screening test of choice for hemodynamically stable patients. A positive US in the stable trauma patient warns the clinician about the possibility of impending hemodynamic deterioration. CT scan and surgical consult should be rapidly facilitated in this group of patients.
      • CT scan: The definitive test for stable abdominal trauma patients. CT scanning will diagnose both solid organ and retroperitoneal injuries better than ultrasound. CT imaging allows a determination of whether an embolization procedure is warranted for hemorrhage control. It is indicated in all stable patients with stab wounds. It is also indicated in patients with gross hematuria, to look for renal injury.
      • Diagnostic peritoneal lavage: Currently used infrequently.
  • Local wound exploration: While frequently used in the past in penetrating abdominal trauma to look for violation of the fascia, it has now also been replaced with CT scanning in the majority of patients (see Diagnostic Tests & Interpretation).

Lab
  • Blood type and screen
  • CBC
  • Electrolytes and creatinine
  • Lipase
  • UA
  • EKG

Imaging
  • Ultrasound: FAST exam focuses on dependent intraperitoneal areas where blood can accumulate which include: Hepatorenal space (Morison pouch), splenorenal space, suprapubic region (bladder and pouch of Douglas), pericardium
    • Advantages:
      • Rapid
      • Noninvasive
      • Can be performed at the patient's bedside concurrent with evaluation and initial resuscitation
      • Does not require contrast agents or ionizing radiation
      • Can be repeated in the case of changes in the patient's hemodynamic status or physical exam
    • Disadvantages:
      • Operator dependent
      • Does not reliably identify solid organ (e.g., spleen and liver lacerations) or retroperitoneal injuries. May be negative with pelvic fractures despite significant hemorrhage. Not sensitive for bowel injury.
    • Contraindications:
      • Absolute: None
      • Relative: Obesity; subcutaneous emphysema
    • Positive test:
      • Demonstration of free fluid or obvious solid organ injury. ∼600 mL free fluid required in adults for a positive right upper quadrant Morison pouch view. ∼150 mL is required for a positive pelvic/suprapubic view (optimally performed prior to Foley placement).
      • Adequate exam includes visualization of the right upper quadrant, left upper quadrant, suprapubic/pelvis, and cardiac areas.
  • CT scan:
    • Advantages:
      • Sensitivity of 85–98%, PPV (for detecting need for laparotomy) of 85%
      • Provides specific and detailed organ injury information
      • May aid in a nonoperative approach to solid organ injuries, which may be managed with observation or interventional radiology mediated embolectomy.
      • Allows imaging of adjacent spinal structures to diagnose fracture.
    • Disadvantages:
      • Costly
      • Possible risk: Up to 1 in 2,000 increase in risk of fatal cancer from radiation
      • Requires IV contrast (with risk of acute contrast reactions and renal toxicity).
      • Isolated diaphragmatic, pancreatic, bowel injuries may be missed, especially if performed immediately after injury.
    • Indications:
      • Hemodynamically stable patients
    • Contraindications:
      • Absolute: Pre-existing indication for exploratory laparotomy; hemodynamic instability; previous contrast reaction
    • Considerations:
      • Many institutions now manage multisystem trauma patients with the “pan–scan,” which includes CT imaging of the head, C-spine, chest, and abdomen/pelvis in 1 session.
      • IV contrast is sufficient in the abdominal trauma patient. Oral and rectal contrast is not needed.
      • Angiography
        • Unstable patients and pelvic fractures
        • This approach can embolize vessels from pelvis, spleen, etc. 

Diagnostic Procedures/Other
  • Diagnostic peritoneal lavage:
    • Advantages:
      • Rapid
      • Helpful in detecting mesenteric and hollow organ injuries
      • May be considered in patients with pelvic fractures and hemorrhage
      • Relatively simple to perform
      • Sensitivity 87–92%, specificity 82%, PPV 52%, NPV 87%
      •  Low complication rate
    • Disadvantages:
      • Invasive
      • Largely replaced by bedside US
      • Does not identify specific organ injury
      • 1–2% complication rate
      • May miss retroperitoneal injuries and intraperitoneal bladder rupture
      • High false-positive rates 
  • Possible indications:
    • Hemodynamically unstable patients
    • Patients requiring emergent surgery for other conditions (e.g., craniotomy for epidural hematoma)
    • Pelvic fractures
  • Contraindications:
    • Absolute: Pre-existing indication for exploratory laparotomy
    • Relative: Previous abdominal surgery, severe abdominal distention, pregnancy, pediatric patients
  • Considerations:
    • Foley catheter and nasogastric tube placement is recommended before beginning the procedure.
  • Contraindications:
    • Blood at urethra
    • High riding prostate
  • Positive test:
    • Aspiration of >10 mL of blood, bile, bowel contents, or urine
    • Diagnostic peritoneal lavage fluid in the urine or chest tube
    • Blunt trauma with >100,000 erythrocytes/mm3
    • Penetrating trauma >1,000 erythrocytes/mm3

Differential Diagnosis

See “Abdominal Trauma (Blunt)” and “Abdominal Trauma (Penetrating).”

Treatment

Pre Hospital

All patients with a significant mechanism of injury or suspicion of major trauma should be triaged to a designated trauma center (preferably a Level 1 Center)
Pediatric Considerations
  • Pediatric patients should be triaged to a pediatric trauma center or to an adult trauma center equipped to manage children.
  • CT scan should be considered the diagnostic test of choice in children.

Initial Stabilization/Therapy

  • In unstable patients, management of the airway, breathing, and circulation with resuscitation of hypovolemic shock and rapid control of major hemorrhage must take precedence.
  • See “Abdominal Trauma (Blunt)” and “Abdominal Trauma (Penetrating).”

Ed Treatment/Procedures

  • See “Abdominal Trauma (Blunt)” and “Abdominal Trauma (Penetrating).”
  • Crystalloid IV therapy is generally warranted with significant abdominal injury.
  • 2 large-bore IV catheters should be placed.
  • Blood transfusion is indicated for all hemodynamically unstable abdominal trauma patients. O negative or O positive blood can be used in men/women beyond childbearing age.
  • Hemodynamically unstable trauma patients with altered mental status and inability to protect airway will usually need endotracheal intubation prior to transfer to operating suite.

Ongoing Care

Disposition

Admission Criteria
  • All unstable trauma patients require admission to the hospital and most will require surgical management.
  • Most multisystem trauma patients who also have abdominal trauma will need admission.
  • Pregnant women >24 wk gestation should be admitted for fetal–maternal monitoring.
  • Stable trauma patients are divided into 3 classes:
    • Gun shot wounds to abdomen: Almost all will require admission. Rate of surgical exploration is high in this category due to elevated risk of organ injury.
    • Stab wounds to abdomen: Patients with penetration of fascia will require admission. US, CT, or physical exam will define patients who need operative management.
    • Blunt abdominal trauma: US, CT, or exam will define patients who need admission.

Discharge Criteria
  • Patients with stable hemodynamics during their ED course with a negative evaluation and reliable follow-up may be considered for discharge.
  • Patients with inability to travel back to the hospital or to contact EMS for aid in case of deterioration must be considered for admission.

Follow-Up Recommendations

A small subset of discharged patients may have an undiagnosed injury (most commonly intestinal or pancreatic). Patients must be instructed to return to the ED with worsening abdominal pain, distention, vomiting, or rectal bleeding.

Pearls and Pitfalls

  • US can be immediately performed at the bedside concurrent with initial stabilization.
  • Consider serial US exams. This is especially important if there is a change in the patient's hemodynamic status or physical exam.
  • Many stable adult and pediatric trauma patients are now being managed nonoperatively based on CT findings.
  • “Pan CT scan” decreases missed injury rate but increases lifetime risk of cancer.
  • With increased use of US and CT, DPL and local wound exploration have become less useful in the evaluation of abdominal trauma.
  • Pitfalls include:
    • Not immediately sending type and screen or checking a pregnancy test
    • Sending pregnant women >24 wk gestation home without fetal–maternal monitoring

Additional Reading

  • Bifflm WL, Kaups KL, Cothren CC, et al. Management of patients with anterior abdominal stab wounds: A western trauma association multicenter trial. J Trauma. 2009;66:1294–1301.  [PMID:19430229]
  • Goodman CS, Hur JY, Adajar MA, et al. How well does CT predict the need for laparotomy in hemodynamically stable patients with penetrating abdominal injury? A review and meta-analysis. AJR. 2009;193.
  • Rose JS. Ultrasound in abdominal trauma. Emerg Med Clin North Am. 2004;22(3):581–599.  [PMID:15301840]

See Also

  • Abdominal Trauma, Blunt
  • Abdominal Trauma, Penetrating

Codes

ICD-9

  • 88.02 Other abdomen tomography
  • 88.19 Other x-ray of abdomen
  • 88.76 Diagnostic ultrasound of abdomen and retroperitoneum
  • 868.00 Injury to other intra-abdominal organs without mention of open wound into cavity, unspecified intra-abdominal organ
  • 868.09 Injury to other and multiple intra-abdominal organs without mention of open wound into cavity
  • 868.10 Injury to other intra-abdominal organs with open wound into cavity, unspecified intra-abdominal organ

ICD-10

  • Plain Radiography of Abdomen
  • Ultrasonography of Abdomen
  • Unspecified injury of abdomen, initial encounter
  • Unsp opn wnd abd wall, unsp quadrant w penet perit cav, init
  • Computerized Tomography (CT Scan) of Abdomen

SNOMED

  • 441987005 Imaging of abdomen (procedure)
  • 45036003 ultrasonography of abdomen (procedure)
  • 169070004 computed tomography of abdomen (procedure)
  • 128069005 Injury of abdomen (disorder)
  • 283475002 Stab wound of abdomen (disorder)
  • 283545005 gunshot wound (disorder)
  • 424863004 unt injury of abdomen (disorder)
  • 443183003 Penetrating wound of abdomen (disorder)

Authors

Alfred A. Joshua


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