ConditionDigestive system
Intestinal Obstruction (Bowel Obstruction)
An intestinal obstruction is a blockage that stops food, fluid and gas from moving through the small or large intestine. It causes waves of cramping abdominal pain, a swollen belly, vomiting and inability to pass stool or gas. The most common causes are scar tissue (adhesions) from previous surgery, hernias and, in the large bowel, cancer. It is a medical emergency, because the trapped bowel can lose its blood supply and burst. Many cases settle with bowel rest and a tube; others need surgery.
Also called: Bowel obstruction, small bowel obstruction (SBO), large bowel obstruction (LBO), blocked bowel, intestinal blockage
At a glance
- What it is
- A mechanical blockage of the small or large intestine.
- Common causes
- Adhesions (most small bowel cases), hernias, cancer (most large bowel cases), Crohn's strictures, volvulus.
- Symptoms
- Cramping pain, bloating, vomiting, no stool or gas.
- Diagnosis
- CT scan of the abdomen.
- Treatment
- Nothing by mouth, IV fluids, a nasogastric tube; surgery for strangulation, complete or persistent obstruction.
When to get help
Call 911 or go to the ER
- Cramping abdominal pain with a swollen belly, vomiting and no gas or stool. Call 911 or your local emergency number
- Constant, severe pain, fever, a rigid tender belly or fast pulse (possible strangulated or perforated bowel)
- Green or brown, foul-smelling vomit
- A painful, hard hernia bulge that cannot be pushed back, with vomiting
See a doctor within a day or two
- Repeated vomiting with abdominal swelling, even if some gas is still passing
- Progressive constipation with bloating and pain in someone with previous abdominal surgery
Book a routine appointment
- Gradually worsening constipation, narrowing stools, blood in stool or weight loss (needs evaluation for colon cancer)
- Recurrent episodes of bloating and cramping after meals in someone with Crohn's disease
How bowel obstruction develops
Normally, waves of muscle contraction move contents through about 6 m (20 feet) of small intestine and 1.5 m (5 feet) of colon. When a blockage occurs:
- fluid and gas build up above the blockage, stretching the bowel
- the bowel tries harder to push past, causing cramping pain
- fluid leaks into the bowel and is vomited, causing dehydration and salt imbalances
- in strangulation, the blood supply is cut off, and the bowel can die (ischemia) and perforate within hours
A closed-loop obstruction, where a segment is blocked at both ends (as in volvulus), is especially dangerous.
Ileus (pseudo-obstruction) causes similar symptoms when the bowel stops moving without a physical blockage, often after surgery or with low potassium. See ileus.
Causes
Small bowel obstruction
| Cause | Notes |
|---|---|
| Adhesions | Scar tissue bands after abdominal or pelvic surgery; the most common cause in adults |
| Hernias | Inguinal, femoral, umbilical, incisional; the leading cause where surgery is less common |
| Crohn's disease | Inflammatory or scarred strictures |
| Tumors | Small bowel tumors or spread from other cancers |
| Intussusception | Bowel telescoping; common in children, rare in adults |
| Gallstone ileus, swallowed objects, bezoars | Less common |
Large bowel obstruction
| Cause | Notes |
|---|---|
| Colorectal cancer | The most common cause |
| Volvulus | Twisting of the sigmoid colon or cecum |
| Diverticulitis | Strictures from repeated inflammation |
| Fecal impaction | Mostly older or immobile people |
Symptoms
- crampy, colicky abdominal pain coming in waves, often around the navel in small bowel obstruction
- abdominal swelling and bloating
- nausea and vomiting; vomiting starts early with high small bowel blockages and later with colon blockages
- no bowel movements or gas (complete obstruction), or diarrhea and small amounts of gas (partial)
- loss of appetite
- loud, high-pitched bowel sounds early on
- signs of dehydration: thirst, dry mouth, low urine
Constant severe pain, fever, a rigid abdomen or fast heart rate suggest strangulation or perforation.
Diagnosis
- Physical exam: distension, tenderness, hernias, surgical scars, rectal exam.
- Blood tests: blood count, electrolytes, kidney function, lactate (raised with bowel ischemia).
- CT scan of the abdomen and pelvis with contrast: the main test. It shows the site, cause and complications such as strangulation.
- Abdominal X-ray: may show dilated loops and air-fluid levels.
- Water-soluble contrast study: given by mouth in adhesive obstruction; if contrast reaches the colon within 24 hours, the obstruction is likely to resolve without surgery.
Treatment
Initial treatment
- Nothing by mouth ("bowel rest")
- IV fluids and correction of electrolytes
- Nasogastric tube through the nose into the stomach to remove fluid and gas, relieving vomiting and distension
- Pain relief and anti-nausea medicines
- Monitoring with repeated exams and blood tests
Many partial adhesive small bowel obstructions resolve within 48 to 72 hours with this treatment.
Surgery
Surgery is needed for:
- signs of strangulation, ischemia or perforation
- complete obstruction or closed-loop obstruction
- incarcerated hernias
- obstruction that does not resolve with conservative treatment, typically within 3 to 5 days
- tumors
Procedures include dividing adhesions, repairing hernias, removing dead or diseased bowel, and sometimes creating a temporary stoma. Laparoscopic surgery is used in selected cases.
Other treatments
- Sigmoid volvulus: untwisting with a flexible scope, followed by planned surgery to prevent recurrence
- Colorectal cancer obstruction: surgery, or a stent placed through a colonoscope as a bridge to surgery or for palliation
- Crohn's strictures: medicines to reduce inflammation, endoscopic dilation or surgery
Complications
- dehydration and kidney injury
- bowel ischemia and perforation
- peritonitis and sepsis
- aspiration pneumonia from vomiting
- recurrence, especially after adhesive obstruction
Prevention
- Minimally invasive surgery reduces adhesion formation.
- Repair hernias that cause symptoms before they become trapped.
- Follow colon cancer screening recommendations.
- In Crohn's disease, keep inflammation controlled.
Frequently asked questions
What are the first signs of a bowel obstruction?
Early signs are cramping abdominal pain that comes in waves, bloating, nausea and vomiting, and difficulty passing gas or stool. If you have had previous abdominal surgery or a hernia and develop these symptoms, seek medical care promptly.
Can a bowel obstruction clear on its own?
Partial obstructions, especially from adhesions, often resolve with hospital treatment: no food, IV fluids and a tube to decompress the stomach. Complete obstructions and those with signs of reduced blood flow need surgery.
What causes a bowel obstruction?
In the small intestine, adhesions from previous surgery are the most common cause, followed by hernias. In the large intestine, colon cancer and volvulus are the most common causes. Crohn's disease and diverticulitis can also cause narrowing.
Can you still poop with a bowel obstruction?
With a partial obstruction, you may still pass some gas or small, loose stools. With a complete obstruction, stool and gas stop completely after the bowel beyond the blockage empties. Passing some stool does not rule out an obstruction.
Sources
This guide was written from current patient and clinical guidance, including:
- World Society of Emergency Surgery: Bologna guidelines for adhesive small bowel obstruction
- American College of Surgeons: Bowel obstruction
- NIDDK: Intestinal obstruction (in digestive disease resources)
- MedlinePlus: Intestinal obstruction
- Merck Manual Professional Version: Intestinal obstruction