Adhesive Small Bowel Obstruction
A small intestine blockage caused by internal scar tissue
Quick Facts
- Type: Digestive (gastrointestinal) emergency
- Cause: Scar tissue (adhesions) after surgery
- Key symptoms: Cramping pain, vomiting, bloating, no stool or gas
- Seek care: Severe pain, fever, hard rigid abdomen
Overview
The small intestine carries food and digestive juices from the stomach toward the large intestine. When it becomes blocked, contents back up and cannot pass normally. This is a small bowel obstruction. The most common cause is adhesions, bands of internal scar tissue that form after abdominal or pelvic surgery and can kink, tether, or compress loops of bowel.
An adhesive small bowel obstruction can be partial, where some contents still pass, or complete, where nothing gets through. While some partial obstructions settle with rest and supportive care, a complete or worsening obstruction can cut off blood supply to the bowel, which is a surgical emergency. Prompt assessment is important because the situation can change quickly.
Symptoms
Symptoms come from contents backing up behind the blockage and from the bowel straining to push past it.
- Crampy, wave-like abdominal pain
- Bloating and a swollen abdomen
- Nausea and vomiting, which may become greenish or foul
- Inability to pass stool or gas (especially in complete obstruction)
- Loud, high-pitched bowel sounds early, which may later fade
- Loss of appetite
Warning signs that need emergency care include constant severe pain (rather than crampy), fever, a rapid heartbeat, and a rigid, very tender abdomen. These can mean the bowel's blood supply is compromised or the bowel has perforated.
Causes
Adhesions are the underlying cause in this type of obstruction. They form as part of the body's healing process:
- Previous abdominal or pelvic surgery: The most common reason adhesions form; even surgery many years earlier can be responsible.
- Past abdominal infection or inflammation: Conditions such as peritonitis or pelvic infection can leave scar tissue.
- Endometriosis or radiation: Less common contributors to adhesion formation.
The adhesions act like internal ropes or sheets that can bend a loop of bowel sharply or squeeze it, narrowing or closing the passage. A loop may also twist around an adhesion, which is more dangerous because it can quickly choke off blood flow.
Risk Factors
- Previous abdominal or pelvic surgery, including appendix and gynecologic operations
- A history of multiple abdominal surgeries
- Past abdominal infection or inflammation
- A previous episode of adhesive bowel obstruction
- Endometriosis or prior abdominal radiation
Diagnosis
Doctors diagnose an obstruction using history, examination, and imaging:
- History and examination: Previous surgery, the pattern of pain and vomiting, and a distended, tender abdomen are key clues.
- Imaging: A CT scan is the most useful test; it confirms the blockage, shows its location, and helps judge whether blood supply is threatened. Plain X-rays may also be used.
- Blood tests: Help assess dehydration, infection, and signs of bowel injury.
Imaging also helps distinguish a partial obstruction that might settle from a complete or strangulated one that needs urgent surgery.
Treatment
Treatment depends on how severe the obstruction is and whether the bowel's blood supply is at risk.
- Bowel rest and support: Many partial obstructions are managed by stopping food and drink, giving intravenous fluids, and decompressing the stomach with a tube through the nose; this often allows the obstruction to settle.
- Close monitoring: The person is watched for improvement or warning signs over hours to a few days.
- Surgery: Needed when the obstruction is complete, does not improve, or shows signs of strangulation. Surgeons release the adhesions and remove any damaged bowel.
Because surgery itself can create new adhesions, doctors often try conservative measures first when it is safe to do so.
Prevention
- Adhesions cannot always be prevented, but minimally invasive surgical techniques may reduce them
- Attend follow-up after abdominal surgery and report new severe abdominal symptoms
- Seek care early for crampy pain with vomiting and no bowel movements, especially after past surgery
- Stay well hydrated and follow any dietary advice if you have had previous obstructions
When to See a Doctor
Seek prompt medical care for cramping abdominal pain with vomiting, bloating, and an inability to pass stool or gas, particularly if you have had abdominal or pelvic surgery in the past. Go to the emergency department right away if the pain becomes constant and severe, you develop a fever or rapid heartbeat, or your abdomen becomes hard and very tender, as these suggest the bowel's blood supply may be cut off and emergency surgery may be needed.
Frequently Asked Questions
What causes adhesive small bowel obstruction?
It is caused by adhesions, bands of internal scar tissue that most often form after abdominal or pelvic surgery. These bands can kink, tether, or compress loops of small intestine, blocking the passage of food and fluids. Adhesions can cause an obstruction even many years after the original operation.
Can an adhesive bowel obstruction resolve without surgery?
Yes, many partial obstructions settle with conservative treatment, which involves resting the bowel, giving intravenous fluids, and using a tube to decompress the stomach. However, a complete obstruction or signs that the blood supply is threatened usually require surgery.
When is bowel obstruction an emergency?
It becomes an emergency when pain turns constant and severe, you develop a fever or rapid heartbeat, or your abdomen becomes rigid and very tender. These suggest the bowel may be strangulated or perforated, which requires immediate surgery. Go to the emergency department without delay.
Does surgery prevent future obstructions?
Surgery to release adhesions relieves the current blockage, but the surgery itself can create new adhesions, so obstructions can recur. For this reason doctors often try non-surgical management first when it is safe, and reserve surgery for cases that do not improve or that show danger signs.
References
- MedlinePlus, U.S. National Library of Medicine. Intestinal obstruction.
- Mayo Clinic. Intestinal obstruction - Symptoms and causes.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Bowel obstruction.
- MedlinePlus, U.S. National Library of Medicine. Abdominal adhesions.