Emergency Medicine · Year 3 · from Emergency Medicine

Case 2: Small Bowel Obstruction - The Surgical Abdomen

Patient Demographics

  • Age: 68 years
  • Sex: Male
  • Occupation: Retired engineer

Chief Complaint

"I've been vomiting all night and my belly is huge."

History of Present Illness

A 68-year-old male presents with 24 hours of progressive abdominal distension, crampy abdominal pain, and intractable vomiting. Initially vomited food contents, now bilious. Reports complete obstipation (no flatus or stool) for 18 hours. Pain is diffuse, crampy, and comes in waves. History of exploratory laparotomy for gunshot wound 30 years ago.

Initial Assessment

ESI Level: 2 - High-risk situation

First Impression:

  • Appearance: Uncomfortable, diaphoretic, distended abdomen visible
  • Work of breathing: Mildly labored (splinting)
  • Circulation: Pale, dry mucous membranes

Vital Signs:

  • Heart rate: 112 bpm
  • Blood pressure: 98/62 mmHg
  • Respiratory rate: 22 breaths/min
  • SpO2: 95% on room air
  • Temperature: 37.8C

Primary Survey

Airway: Patent, but vomiting bilious material Breathing: Tachypneic, diminished bases (diaphragm elevation) Circulation: Tachycardic, hypotensive, dry mucous membranes, delayed capillary refill Disability: Alert but uncomfortable, GCS 15 Exposure: Massive abdominal distension, well-healed midline surgical scar

Resuscitation

Immediate Interventions:

  1. NPO, nasogastric tube placement - 800mL bilious output
  2. Two large-bore IVs
  3. Aggressive fluid resuscitation: 2L LR bolus
  4. Foley catheter - minimal output initially
  5. Labs and imaging ordered

Secondary Survey

SAMPLE History:

  • Symptoms: Abdominal pain, vomiting, distension, obstipation
  • Allergies: Sulfa drugs
  • Medications: Lisinopril, metformin, aspirin
  • PMH: Hypertension, type 2 DM, prior abdominal surgery
  • Last Meal: Yesterday lunch
  • Events: Progressive symptoms over 24 hours

Surgical History:

  • Exploratory laparotomy 1992 (trauma)
  • Cholecystectomy 2010

Physical Examination:

Abdominal Exam:

  • Inspection: Significantly distended, midline and RUQ scars
  • Auscultation: High-pitched, tinkling bowel sounds
  • Percussion: Tympanitic throughout
  • Palpation:
  • Diffusely tender, worse periumbilically
  • Moderate guarding but no rigidity
  • No focal peritoneal signs initially
  • No hernias at incision sites

Concerning Features for Strangulation:

  • Tachycardia: Present
  • Fever: Low-grade
  • Localized tenderness: Developing
  • Peritoneal signs: Not yet
  • Leukocytosis: Pending

Diagnostic Testing

Labs:

  • WBC: 16,800 with left shift
  • Hgb: 16.2 (hemoconcentration)
  • BMP: Na 132, K 3.1, Cl 94, HCO3 20, BUN 42, Cr 1.8
  • Lactate: 3.4 mmol/L (concerning)
  • Lipase: Normal

Imaging:

Abdominal X-ray:

  • Dilated loops of small bowel (>3cm)
  • Multiple air-fluid levels
  • No free air
  • Minimal colonic gas

CT Abdomen/Pelvis with IV contrast:

  • Small bowel obstruction with transition point in RLQ
  • Dilated proximal small bowel up to 4.5cm
  • Decompressed distal small bowel
  • Adhesive band identified as cause
  • Small bowel feces sign present
  • Concerning finding: Bowel wall thickening and decreased enhancement at transition point, possible early ischemia

Diagnosis

High-grade small bowel obstruction secondary to adhesive disease with concern for early strangulation

Management

Resuscitation Continued:

  • Total 4L crystalloid with improved hemodynamics
  • Electrolyte repletion: K+ and Cl-
  • NG tube on continuous low wall suction
  • Foley monitoring (UOP improving with resuscitation)

Surgical Consultation:

  • Given concerning CT findings (wall thickening, decreased enhancement, elevated lactate)
  • Decision for operative intervention

Operative Findings:

  • Single adhesive band causing complete SBO
  • Loop of small bowel with serosal changes but viable after lysis
  • No bowel resection required
  • Return of peristalsis noted

Disposition

  • Post-operative ICU admission (given degree of resuscitation)
  • Continued NGT decompression
  • Serial abdominal exams
  • Advance diet when NGT output minimal and bowel function returns
  • Discharged home on POD 4

Teaching Points

  1. Cardinal features of SBO: Abdominal pain, vomiting, distension, and obstipation (absence of flatus/stool)
  2. Most common cause: Adhesions from prior surgery (75% of SBO cases)
  3. Strangulation signs: Fever, tachycardia, localized tenderness, peritoneal signs, leukocytosis, elevated lactate - warrant emergent surgery
  4. CT findings concerning for strangulation: Bowel wall thickening, decreased enhancement, mesenteric haziness, closed-loop configuration
  5. Non-operative management: Appropriate for partial SBO without strangulation; failure rate ~25%
  6. Third-spacing: Massive fluid shifts require aggressive resuscitation; monitor UOP

Clinical Image

Image Description: Coronal CT image demonstrating multiple dilated loops of small bowel with air-fluid levels proximal to a transition point (arrow), with decompressed distal small bowel, consistent with high-grade small bowel obstruction.

Attribution: Image from Radiopaedia.org, Case courtesy of Dr. Andrew Dixon. Licensed under CC BY-NC-SA 3.0. Source: https://radiopaedia.org/cases/small-bowel-obstruction-adhesive

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