Basics
Description
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 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
- Associated injuries:
- Liver and splenic lacerations; thoracic and pelvic fractures
- Seatbelt 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 pain
- Intestinal obstruction
- Decreased urine output
- Tachycardia
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 injury
- Incidence 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 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.
- 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 CT
- Sensitive for hemoperitoneum but not source of bleeding
- Positive if RBC count of >100,000/mm3
- Lavage 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:
- 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.
- 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)