Bowel Obstruction: Mechanical vs Paralytic Ileus — Active Blockage vs Silent Gut
You hear high-pitched tinkling bowel sounds on one patient and dead silence on another — both abdomens are distended. Picking the wrong intervention wastes critical time: one may need an emergency surgeon while the other needs ambulation and patience.
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- Physical blockage of bowel lumen
- Adhesions, hernia, tumor
- Volvulus, intussusception
- Loss of peristalsis, no blockage
- Post-op (most common)
- Opioids, hypokalemia
- ★High-pitched, hyperactive sounds (early)
- Crampy colicky pain
- Feculent vomiting if distal
- ★Absent or hypoactive bowel sounds
- Dull constant diffuse pain
- Distension > vomiting
- ★X-ray: air-fluid levels, stepladder
- Dilated loops proximal to blockage
- X-ray: diffuse gas, no transition point
- Check K⁺/Mg²⁺ for cause
- NPO, IV fluids, NG decompression
- Urgent surgical consult
- NPO, IV fluids, NG decompression
- Ambulation
- Correct K⁺/Mg²⁺
- Limit opioids
- High surgery likelihood if complete
- Surgery if strangulated or not resolving
- Resolves conservatively in 2–5 days
- Surgery rarely needed
- Report no flatus or stool
- Report a hard, painful hernia bulge
- Walking restores bowel function
- Passing flatus signals recovery
- Report no flatus or stool
- Fever, rebound tenderness, tachycardia
- Suspect strangulation / perforation
- Worsening distension
- No bowel sounds by post-op day 3–5
- Worsening distension
- Strangulation → bowel ischemia
- Perforation, peritonitis
- Aspiration from vomiting
- Prolonged ileus
- Aspiration from vomiting
Mechanical Obstruction
- Physical blockage of bowel lumen
- Adhesions, hernia, tumor
- Volvulus, intussusception
Paralytic Ileus
- Loss of peristalsis, no blockage
- Post-op (most common)
- Opioids, hypokalemia
Mechanical Obstruction
- ★High-pitched, hyperactive sounds (early)
- Crampy colicky pain
- Feculent vomiting if distal
Paralytic Ileus
- ★Absent or hypoactive bowel sounds
- Dull constant diffuse pain
- Distension > vomiting
Mechanical Obstruction
- ★X-ray: air-fluid levels, stepladder
- Dilated loops proximal to blockage
Paralytic Ileus
- X-ray: diffuse gas, no transition point
- Check K⁺/Mg²⁺ for cause
Mechanical Obstruction
- NPO, IV fluids, NG decompression
- Urgent surgical consult
Paralytic Ileus
- NPO, IV fluids, NG decompression
- Ambulation
- Correct K⁺/Mg²⁺
- Limit opioids
Mechanical Obstruction
- High surgery likelihood if complete
- Surgery if strangulated or not resolving
Paralytic Ileus
- Resolves conservatively in 2–5 days
- Surgery rarely needed
Mechanical Obstruction
- Report no flatus or stool
- Report a hard, painful hernia bulge
Paralytic Ileus
- Walking restores bowel function
- Passing flatus signals recovery
- Report no flatus or stool
Mechanical Obstruction
- Fever, rebound tenderness, tachycardia
- Suspect strangulation / perforation
- Worsening distension
Paralytic Ileus
- No bowel sounds by post-op day 3–5
- Worsening distension
Mechanical Obstruction
- Strangulation → bowel ischemia
- Perforation, peritonitis
- Aspiration from vomiting
Paralytic Ileus
- Prolonged ileus
- Aspiration from vomiting
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Tinkling, fighting gut = mechanical blockage — call the surgeon. Silent, lazy gut = ileus — get the patient walking.
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