Bowel Obstruction

What is a bowel obstruction?

A bowel obstruction is a partial or complete blockage of either of your bowels — your small intestine or your large intestine. Your intestines move food and (eventually) food waste from your stomach to your rectum, which you pass as stool when you poop. An obstruction blocks your intestinal passageway, slowing movement or grinding digestive processes to a halt.

Waste, gas and digestive juices can get stuck behind the blockage, damaging the tissue. The blockage can prevent your bowel from working as it should, leading to dangerous complications.

With a bowel obstruction, time is of the essence. If you’re noticing symptoms of an obstruction, call a healthcare provider or get to an emergency department (ED) right away.

Types of bowel obstruction

Healthcare providers classify bowel obstructions based on which intestine they affect:

• Small bowel obstruction: Most obstructions (approximately 80%) happen in your small intestine. Your small intestine connects to your stomach at one end and your large intestine at the other. In addition to moving food and water along to your large intestine, your small intestine breaks down foods and absorbs water and nutrients from them.
• Large bowel obstruction: Your large intestine includes your colon and rectum. It continues the nutrient absorption process that starts in your small intestine. It also transforms food and water into waste material you pass as stool. Large bowel obstructions account for about 20% of all intestinal blockages.

Bowel obstructions can also be:

• Complete: A total blockage in the affected part of your intestine.
• Partial: A partial blockage or narrowing of the affected part.
• Pseudo: A “false” obstruction, where you experience the symptoms of a bowel obstruction when you don’t have one. Scientists believe pseudo-obstructions may be related to nerves glitching in your intestines, but they need to do more research.

How common are bowel obstructions?

Small bowel (intestine) obstructions are a common reason people visit the ED.

Large bowel obstructions are uncommon in the general population, but they’re frequent among people with colon cancer. About 40% of people with colon cancer get diagnosed because bowel obstruction symptoms (from a tumor) prompted them to seek emergency care.

What are the symptoms of small bowel obstruction?

You may have sharp stomach pains that come in waves. Eventually, the pain may become constant. You may also have one or more of these symptoms:

• Abdominal pain, cramping or bloating.
• Nausea and vomiting.
• Lack of appetite.
• Malaise (an overall feeling of illness).
• Diarrhea (usually a sign of a partial blockage).
• Rapid heartbeat, dark-colored pee (urine) and other signs of dehydration.
• Severe constipation (in cases of complete obstruction, you won’t be able to pass gas or poop).

Infants and children experience the same symptoms as adults. Infants can’t tell you where it hurts, but they may pull their legs up toward their bellies and cry. Other symptoms of bowel obstructions in children include:

• Fever.
• Blood in stool (rectal bleeding).
• Green or yellow-green vomit.
• Lethargy (being less active than usual).
• Swollen, firm belly.

What does a bowel obstruction feel like?

A bowel obstruction can feel different depending on which intestine is affected and what’s happening in your gut.

An obstruction typically feels like severe cramping pain in your abdomen. The pain from a small bowel obstruction is more likely to come in short intermittent waves, occurring every few minutes or so. The pain is more likely to feel concentrated in one place.

The cramping from a large bowel obstruction tends to be more continuous. The pain is more likely to feel spread out.

Regardless of the specifics, if you’re having severe cramping alongside symptoms like bloating and vomiting, seek immediate care.

Can you still poop with a bowel obstruction?

It’s possible. It depends on where the blockage is and how serious it is. For example, while pooping may be more difficult, you may still have stool with a partial bowel obstruction. Pooping and even passing gas will likely be impossible with a complete bowel obstruction.

What causes a bowel obstruction?

The most common causes of bowel obstructions include:

• Abdominal adhesions (scar tissue) from surgeries: Adhesions are bands of scar tissue that may form after surgery on your abdomen or pelvis. Earlier abdominal surgery is the leading risk factor for small bowel obstruction in the U.S.
• Hernias: Segments of your intestine may break through a weakened section of your abdominal wall. Your bowel can become obstructed if it’s trapped or tightly pinched in the place where it pokes through. Hernias are the second most common cause of small bowel obstruction in the U.S.
• Cancerous tumors: Cancerous tumors may form in your intestines or spread there from other parts of your body (metastatic cancer). These growths can cause partial or total blockages. Colon cancer is the leading cause of large bowel obstructions.

Other causes of bowel obstructions include:

• Inflammatory bowel disease (IBD): Inflammatory bowel diseases, such as Crohn’s disease, can cause scar tissue to form in your intestinal walls. The scar tissue can build up and cause narrowing in your bowel (strictures). 
• Diverticulitis: Diverticulitis occurs when small pockets called diverticula form in your colon and become inflamed. The swelling can cause your colon to narrow. As with IBD, scarring can occur that causes your colon to narrow.
• Intussusception: Intussusception is the main cause of bowel obstructions in children younger than 3. With this condition, one segment of the intestine collapses inside another segment (like a telescope). The collapsed segments can block the bowel and blood flow.
• Volvulus: Some infants are born with a congenital condition (present at birth) called malrotation, where their intestines don’t form properly. This condition can cause their intestines to twist (volvulus), resulting in a blockage. Adults can get twisted intestines, too, but this is rare.
• Radiation therapy to your abdomen, pelvis or rectum: Radiation enteritis is a complication of radiation therapy that occurs when the radiation causes scarring in healthy tissue. The scarring can cause strictures that obstruct your bowels.
• Ingesting a foreign object: Eating something your body can’t break down and process (like non-food items) can obstruct your intestines.

What are the complications of a bowel obstruction?

The complications of a bowel obstruction are life-threatening without emergency care.

• Perforation and infection: The fluids, gases and digestive juices that build up behind the obstruction can create ballooning pressure that causes your intestine to tear (perforation). The contents can leak out, putting you at risk of an abdominal infection called peritonitis and a life-threatening system-wide infection called sepsis.
• Strangulation (tissue death): With strangulation, an obstruction prevents parts of your intestine from getting enough blood. Eventually, gangrene sets in as the tissue dies, putting you at risk of serious infection and even death.

How is a bowel obstruction diagnosed?

As a bowel obstruction is a medical emergency, diagnosis usually happens quickly. It may happen alongside treatment, so no time is lost. Diagnosis may involve:

• Medical history: Your healthcare provider will ask about your medical history, including whether you’ve had any previous abdominal surgeries.
• Physical examination: Your provider will perform a physical exam to check for a swollen abdomen or masses. They may use a stethoscope to listen for bowel sounds that signal an obstruction.
• Blood tests: You may need a complete blood count and electrolyte analysis. A blood test checks for signs of infection. Electrolyte levels can show if you have severe dehydration. If so, you’ll need fluids immediately.

Imaging procedures allow your provider to view the obstruction and check for complications. These include:

• Abdominal X-rays: Abdominal X-rays can show a blockage’s location. These images can also show air around your intestines or diaphragm (the muscle that separates your stomach and chest). Air in these places can indicate a dead section of intestine or a rupture.
• Computed tomography (CT) scan: A CT scan provides more detailed photos than X-rays. You may need one to confirm your diagnosis and give more accurate information about where the bowel obstruction is and what’s caused it.
• Barium enema X-ray: A barium enema X-ray is an X-ray of your colon. While you’re sedated with anesthesia, a provider inserts a catheter (thin tube) into your rectum. The catheter fills your intestine with a safe liquid that travels through your colon while a machine takes X-rays. The liquid makes your intestine stand out more clearly on the X-rays.

These imaging procedures use radiation. You may need alternatives to these procedures if radiation exposure (even at safe levels) poses any potential risk. Children and people who are pregnant may need ultrasounds or MRIs, which don’t use radiation.

What is the treatment for a bowel obstruction?

Most people with bowel obstruction need prompt treatment in the hospital. Complete obstructions usually require immediate surgery. Partial bowel obstructions may require treatments to stabilize your condition, followed by nonsurgical solutions, like bowel rest. It all depends on how severe the obstruction is.

Treatment may include:

• Intravenous (IV) fluids: You may need IV fluids and electrolytes to treat dehydration.
• Nasogastric tube: You may need a nasogastric tube to suction out fluids and air backed up from the blockage. A nasogastric tube is a long, thin tube that goes in through your nose but reaches down into your stomach or intestines.
• Medications: You may need anti-emetics to prevent nausea and vomiting and pain relievers to keep you more comfortable.
• Bowel rest: You may need to refrain from eating or drinking to give your intestine time to clear the obstruction or shrink to its normal size. Or you may only be allowed to drink a special liquid containing the nutrients you’d otherwise get from food.
• Surgery: You’ll likely need surgery if your intestine is completely blocked. Your healthcare provider may remove adhesions or tumors that are causing a blockage. Rarely, they may need to remove diseased segments of tissue. Sometimes, your provider can place a stent (a mesh tube) to keep your intestine open and resolve the obstruction without additional surgery. Or you may need a stent as a temporary solution until you’re healthy enough for surgery to repair the obstruction.

What can I expect if I have a bowel obstruction?

Most people with bowel obstructions improve after treatment. Being able to pass gas again, feeling less bloated and being able to have bowel movements again are all signs your bowel obstruction is clearing.

On the other hand, if an obstruction causes a rupture, the condition can be life-threatening. It’s essential to seek care as soon as you notice symptoms to get treated before a complication happens.

When should I call my healthcare provider?

Call your healthcare provider if you experience:

• Fever.
• Persistent vomiting.
• Severe abdominal pain or cramping that comes and goes.
• Signs of dehydration.

What questions should I ask my healthcare provider?

Questions to ask include:

• What caused my bowel obstruction?
• What treatment will I need?
• Am I at risk of a future bowel obstruction?
• What treatment complications should I be aware of?
• How should I adjust my diet and activity levels while I’m recovering?