Chart — Gastrointestinal
Small vs Large Bowel Obstruction Chart
The higher the blockage, the earlier and more violent the vomiting; the lower it is, the more dramatic the distension. That single trade-off sorts most SBO from LBO at the bedside.
Educational use only. Patterns overlap and imaging confirms the level and cause. Either type can strangulate — escalate constant pain, fever, and peritoneal signs. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Side by Side
| Feature | Small bowel (SBO) | Large bowel (LBO) |
|---|---|---|
| Onset | Rapid | Gradual |
| Vomiting | Early and profuse; may be bilious or feculent | Late or absent |
| Distension | Less / mid-abdominal | Marked / generalized |
| Pain | Colicky, upper/periumbilical, frequent waves | Lower abdominal, cramping, less frequent |
| Obstipation | May still pass some stool early | Early obstipation (no stool/gas) |
| Common causes | Adhesions, hernias, intussusception | Tumor (colorectal cancer), volvulus, diverticular stricture |
| Acid-base / electrolytes | Metabolic ALKALOSIS (loses gastric acid), hypokalemia, dehydration | Less marked; can trend toward acidosis if prolonged |
Exam Traps
- ✦SBO = early profuse vomiting + metabolic ALKALOSIS; LBO = marked distension + early obstipation.
- ✦Adhesions and hernias cause most SBOs; colorectal cancer is a leading LBO cause.
- ✦Feculent vomiting signals a distal/long-standing small-bowel obstruction.
- ✦Core care for both: NPO + NG suction, IV fluids, replace potassium; count NG output as loss.
- ✦Constant (not crampy) pain + fever + rising WBC + peritoneal signs = strangulation → surgery.
Related Resources
Standards & sources
Fact-checked Jun 21, 2026This page is written to align with American College of Gastroenterology (ACG) / AGA · ASPEN (nutrition support). It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →