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Small-Bowel Injury, Emergency Medicine

Basics

Description

- Blunt: - 3rd most commonly injured organ (5 " 10% of all blunt trauma victims) - Motor vehicle accidents - Nonvehicular trauma: Abuse/assault, bicycle handlebars, large-animal kick - Blast victims

- Mortality rate from small-bowel injury is 33%. - Mesenteric tears may initially be asymptomatic: - Deceleration injury at fixed points (e.g., ligament of Treitz) - Shearing mechanisms near fixed points (e.g., ileocecal junction, adhesions) - Compressive force against anterior spine - Bursting or "blowout " at antimesenteric margin from sudden closed-loop intraluminal pressure rise

- Small-bowel injury may initially be obscured by abnormal mental status, severe associated injuries. - Small-bowel injury not initially apparent may be indicated by: - Progressive abdominal pain - Intestinal obstruction - Decreased urine output - Tachycardia

- CT: - Diagnostic standard for solid-organ injury and head trauma but is less sensitive for hollow viscus injuries - Newest-generation helical CT scanners have a sensitivity of 88% and a specificity of 99%. - The benefits of oral contrast are controversial; it is acceptable to use IV contrast only - Blunt trauma: - Used in stable patients - Indications for CT in blunt trauma include abdominal tenderness, hypotension, altered mental status (GCS <14), costal margin tenderness, abnormal CXR, HCT <30% and hematuria - Specific signs for small-bowel injury on CT are pneumoperitoneum (sensitivity 50 " 75%) and extravasation of contrast (sensitivity 12%). - Signs on CT suggestive of small-bowel injury include unexplained free intraperitoneal fluid (most sensitive 93%), thickened bowel wall >3 mm (61% sensitive), intramural hematomas (75 " 88% sensitive), interloop fluid, mesenteric streaking.

- Immediate transfer to OR is required for patients with an indication for laparotomy: - Evisceration - Abdominal pain with hypotension - Positive DPL or abdominal CT - Thoracic abdominal herniation visualized on chest radiograph - Impaled foreign body - Penetrating gunshot wound to the abdomen - Tetanus and antibiotic prophylaxis should be given for penetrating abdominal wounds and blunt injury requiring surgical exploration.

2 general causes:

  • Blunt visceral trauma
  • Penetrating: Visceral injury (96% of gunshot wounds, 50% of stabbings) " serosal tear, bowel wall hematoma, perforation, bowel transection, mesenteric hematoma/vascular injury

Etiology

  • Blunt:3rd most commonly injured organ (5 " 10% of all blunt trauma victims)Motor vehicle accidentsNonvehicular trauma: Abuse/assault, bicycle handlebars, large-animal kickBlast victims
  • Mortality rate from small-bowel injury is 33%.
  • Mesenteric tears may initially be asymptomatic:Deceleration injury at fixed points (e.g., ligament of Treitz)Shearing mechanisms near fixed points (e.g., ileocecal junction, adhesions)Compressive force against anterior spineBursting or "blowout " at antimesenteric margin from sudden closed-loop intraluminal pressure rise
  • Associated injuries:Liver and splenic lacerations; thoracic and pelvic fracturesSeatbelt syndrome: Abdominal wall ecchymosis, small-bowel injury; Chance fracture of L1, L3
  • Penetrating:Small bowel is the 2nd most commonly injured organ (32%) in anterior abdominal stabbing.Small-bowel injury is most common in gunshot wounds (49%).
  • Blunt:Less common in children (1 " 8% of all blunt pediatric trauma)Lower chance of intestinal injury in vehicular accidents when both shoulder and lap belts are worn.Be cautious of nonpenetrating trauma: Airgun accidents at close range (<10 ft)Consider the possibility of nonaccidental trauma.

Diagnosis

Signs and Symptoms

  • Physical signs and symptoms are unreliable
  • Delays in diagnosis are common
  • Presence of a "seatbelt sign " doubles the risk for small-bowel injury.
  • Initial presentation may be mild:Uniformly, patients will progress to serious signs/symptoms.
  • Delays in diagnosis add to morbidity and mortality:Mortality is 2% when diagnosis is made within 8 hr; 31% when made after 24 hr.

History

  • History of blunt or penetrating abdominal trauma
  • Must consider in ill children without a definite history of trauma (child abuse)

Physical Exam

  • In awake, alert patients look for:Abdominal tenderness (87 " 98%)Abdominal pain (85%)Peritoneal signs (67%)
  • Many patients will have:Abdominal wall bruising (54%)Hypotension (38%)Guaiac-positive rectal exam (5%)
  • Small-bowel injury may initially be obscured by abnormal mental status, severe associated injuries.
  • Small-bowel injury not initially apparent may be indicated by:Progressive abdominal painIntestinal obstructionDecreased urine outputTachycardia

Essential Workup

  • Initial physical exam should note all wounds and areas of tenderness.
  • CT for all medically stable patients
  • For patients with a negative CT scan in which there is high suspicion of bowel injury, further evaluation or serial exams are indicated.
  • For medically unstable patients, diagnostic peritoneal lavage (DPL) is superior to US in determining presence of a hollow viscus injury.

Diagnosis Tests & Interpretation

Lab

  • No diagnostic test has proven highly sensitive in the prediction of small-bowel injury.
  • Serum amylase, lipase, and liver function tests have poor sensitivity for acute injury.

Imaging

  • Plain radiography of chest/abdomen:Not useful for small-bowel injuryIncidence of pneumoperitoneum visible on plain radiograph is only 8%.
  • CT:Diagnostic standard for solid-organ injury and head trauma but is less sensitive for hollow viscus injuriesNewest-generation helical CT scanners have a sensitivity of 88% and a specificity of 99%.The benefits of oral contrast are controversial; it is acceptable to use IV contrast onlyBlunt trauma:Used in stable patientsIndications for CT in blunt trauma include abdominal tenderness, hypotension, altered mental status (GCS <14), costal margin tenderness, abnormal CXR, HCT <30% and hematuriaSpecific signs for small-bowel injury on CT are pneumoperitoneum (sensitivity 50 " 75%) and extravasation of contrast (sensitivity 12%).Signs on CT suggestive of small-bowel injury include unexplained free intraperitoneal fluid (most sensitive 93%), thickened bowel wall >3 mm (61% sensitive), intramural hematomas (75 " 88% sensitive), interloop fluid, mesenteric streaking.Penetrating: CT is not recommended because sensitivity is only 14%; false-negative result rate is 18%.
  • US: Not sensitive in hollow viscus injury because air in bowel makes visualization difficult

Diagnostic Procedures/Surgery

  • DPL:Invasive but may be helpful in unstable patients or in patients with clinically suspicious but nondiagnostic abdominal CTSensitive for hemoperitoneum but not source of bleedingPositive if RBC count of >100,000/mm3Lavage amylase >20 IU/L and leukocyte count >500/mm3 (late markers of small-bowel injury)Lavage microscopy for succus/vegetable matter/feces is specific for small-bowel injury but not sensitive.Lavage alkaline phosphatase (>3 IU/L) is reported to be a useful immediate marker of small-bowel injury.
  • Laparoscopy: Plays a key role in diagnosing small-bowel injury in stable patients with progressive signs or symptoms

Differential Diagnosis

  • Hemoperitoneum owing to vascular insult
  • Solid visceral organ injury or gastric/colon/rectum perforation
  • Vertebral injury and associated ileus

Delay in diagnosis of 1 " 2 days is common and increases morbidity.

Treatment

Pre-Hospital

  • Patients should be transported to the nearest trauma center.
  • Do not attempt to replace eviscerated abdominal contents; cover with moist gauze, blanket, and transport.
  • Do not remove impaled objects in the abdomen; stabilize the object with gauze and tape and transport.

Initial Stabilization/Therapy

  • Standard advanced trauma life support protocols, including airway, breathing, and circulation management
  • Aggressive fluid resuscitation, central line suggested with pressure infusion of warmed IV fluid (lactated Ringer solution or normal saline)
  • Cover eviscerated small bowel with moist gauze; do not remove impaled foreign body in ED.

Ed Treatment/Procedures

  • Immediate transfer to OR is required for patients with an indication for laparotomy:EviscerationAbdominal pain with hypotensionPositive DPL or abdominal CTThoracic abdominal herniation visualized on chest radiographImpaled foreign bodyPenetrating gunshot wound to the abdomenTetanus and antibiotic prophylaxis should be given for penetrating abdominal wounds and blunt injury requiring surgical exploration.
  • Local wound exploration is safe for abdominal stab wounds.
  • Serial abdominal exams and observation for otherwise stable patients
  • Judicious analgesia as BP permits after diagnosis is established

Medication

  • Cefotetan (Cefotan): 1 " 2 g (peds: 20 mg/kg) IV q12h or
  • Cefoxitin (Mefoxin): 1 " 2 g (peds: 40 mg/kg) IV q6h or
  • Ceftizoxime (Cefizox): 1 " 2 g (peds: 50 mg/kg) IV q8 " 12h +
  • Metronidazole: 500 mg (peds: 7.5 mg/kg) IV q6h

Follow-Up

Disposition

Admission Criteria

  • Indication for laparotomy
  • Abnormal mental status/intoxication with abdominal injury
  • Presence of abdominal pain, tenderness (even with a negative workup) mandates admission for observation and serial exams.
  • Stab and gunshot wounds that violate the abdominal fascia, positive DPL, or worsening findings on clinical exam

Discharge Criteria

  • Minimal mechanism blunt trauma in a sober patient with normal exam result who has no abdominal pain and will receive adequate follow-up
  • Explicit discharge instructions to return for worsening signs/symptoms are important to identify those with unsuspected injury.
  • Penetrating wounds that do not violate abdominal fascia

Followup Recommendations

Discharged patients who develop abdominal complaints should return promptly to the ED.

Pearls and Pitfalls

  • Small-bowel injury should be considered in any blunt/penetrating abdominal trauma victim.
  • Initial presentation of patients with small-bowel injuries may be unimpressive.
  • Presence of a "seat belt sign " doubles the risk for small-bowel injury.
  • CT scanning may miss a significant percentage of small-bowel injuries.
  • Observation and serial exams are an important aspect of detecting occult injuries.

Additional Reading

  • CDC Fact Sheet "Blast Injuries: Abdominal Blast Injuries " 2009. Available at www.emergency.cdc.gov/Blastinjuries.
  • Cordle R, Cantor R. Pediatric trauma. In: Rosen P, ed. Rosens Emergency Medicine: Concepts and Clinical Practice. 7th ed. St. Louis, MO: CV Mosby; 2009.
  • Diercks DB, Mehrotra A, Nazarian DJ. Clinical policy: Critical issues in the evaluation of adult patients presenting to the emergency department with acute blunt abdominal trauma. Ann Emerg Med. 2011;57:387 " 404.
  • Gross E, Martel M. Multiple trauma. In: Rosen P, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed. St. Louis, MO: CV Mosby; 2009.
  • Herr S, Fallat ME. Abusive abdominal and thoracic trauma. Clin Ped Emerg Med. 2006;7:149 " 152.

Codes

ICD9

  • 863.20 Injury to small intestine, unspecified site, without open wound into cavity
  • 863.29 Other injury to small intestine, without mention of open wound into cavity
  • 863.30 Injury to small intestine, unspecified site, with open wound into cavity
  • 863.39 Other injury to small intestine, with open wound into cavity
  • 863.21 Injury to duodenum, without open wound into cavity
  • 863.2 Injury to small intestine without mention of open wound into cavity
  • 863.31 Injury to duodenum, with open wound into cavity
  • 863.3 Injury to small intestine with open wound into cavity

ICD10

  • S36.409A Unsp injury of unsp part of small intestine, init encntr
  • S36.429A Contusion of unsp part of small intestine, init encntr
  • S36.439A Laceration of unsp part of small intestine, init encntr
  • S36.499A Other injury of unsp part of small intestine, init encntr
  • S36.419A Primary blast injury of unsp part of small intestine, init
  • S36.420A Contusion of duodenum, initial encounter
  • S36.430A Laceration of duodenum, initial encounter
  • S36.490A Other injury of duodenum, initial encounter

SNOMED

  • 125627008 Injury of small intestine (disorder)
  • 262855004 Laceration of small intestine (disorder)
  • 262853006 Contusion of small intestine (disorder)
  • 210114006 Injury of small intestine with open wound into abdominal cavity (disorder)
  • 125628003 Injury of duodenum (disorder)
  • 64834002 Traumatic perforation of small intestine
  • 68734002 Injury of small intestine without open wound into abdominal cavity (disorder)