Gastrointestinal · Year 2 · from Gastrointestinal
Case 3: Small Bowel Obstruction
Patient Presentation
Demographics: 65-year-old female
Chief Complaint: Crampy abdominal pain, vomiting, and inability to pass gas for 24 hours
History of Present Illness: The patient developed crampy, periumbilical abdominal pain that comes in waves. She has vomited multiple times, initially bilious and now feculent. She has not passed gas or had a bowel movement in 24 hours. The pain is worsening.
Past Medical History: Hysterectomy 15 years ago for fibroids, appendectomy in childhood
Surgical History: Total abdominal hysterectomy, open appendectomy
Physical Examination
- Vital Signs: BP 105/65 mmHg, HR 112 bpm, Temperature 37.8C
- General: Female in moderate distress, appears dehydrated
- Abdomen: Distended, tympanitic, diffuse tenderness without rebound or guarding; well-healed lower midline scar; high-pitched bowel sounds with rushes
- Rectal: Empty vault, no masses
Workup and Results
- CBC: WBC 12,500 with left shift
- BMP: BUN 35, Cr 1.4, K 3.2 (hypokalemic from vomiting)
- Lactate: 1.8 mmol/L (mildly elevated)
- Abdominal X-ray: Multiple dilated small bowel loops with air-fluid levels; minimal colonic gas
- CT Abdomen with Contrast: Small bowel obstruction with transition point in the pelvis; dilated proximal loops, decompressed distal bowel; no pneumatosis or free air; likely adhesive band
CT scan demonstrating small bowel obstruction with dilated, fluid-filled loops of proximal small bowel and a transition point (arrow) where bowel caliber abruptly changes to decompressed distal loops, consistent with adhesive obstruction.
Image Source: Case courtesy of Radiopaedia.org
Diagnosis
Adhesive Small Bowel Obstruction
Clinical Correlation
Adhesions from prior abdominal surgery are the most common cause of small bowel obstruction (60-70% of cases). The patient's previous hysterectomy created adhesive bands that can kink or compress bowel. Proximal to the obstruction, bowel dilates as gas and secretions accumulate. The third-spacing of fluid causes dehydration and electrolyte abnormalities. Complete obstruction prevents passage of gas and stool (obstipation). The transition point on CT identifies where dilated bowel meets decompressed bowel. Signs concerning for strangulation include fever, tachycardia, elevated lactate, and peritoneal signs.
Treatment
- NPO, nasogastric tube placement for decompression
- Aggressive IV fluid resuscitation with electrolyte replacement
- Serial abdominal examinations
- Gastrografin (water-soluble contrast) challenge: if contrast reaches colon within 24 hours, resolution likely; if not, surgery indicated
- Close monitoring for signs of strangulation (would mandate immediate surgery)
- If no improvement in 48-72 hours or clinical deterioration, surgical exploration with adhesiolysis