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Bowel obstruction

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Fast facts

What is bowel obstruction?

Bowel obstruction occurs when you have a complete or partial blockage of your bowel. The blockage stops liquids, solids and gas passing through your small or large intestine (bowel).

Bowel obstruction is a serious condition that requires prompt medical treatment. It can occur at any age, but is more common in the young and in the elderly.

Causes

Anatomy of the bowel

The bowel is a major part of the digestive system, which also includes the liver and the stomach. The bowel is made up of the small and large intestines. When food leaves the stomach, it enters the small intestine, a long and narrow tube (about 20 feet long and one inch wide) that is important for absorbing most of the nutrients in our food. The small intestine is made up of three sections - the duodenum, the jejunum and the ileum. The jejunum and ileum move freely within the abdominal cavity, and are therefore at risk of twisting and forming a mechanical obstruction known as a volvulus (see below).

The small intestine empties into the large intestine, a wider and shorter tube (about 5 feet long and two and a half inches wide). It is mostly used for storing feces and absorbing water. The large intestine is made up of the caecum, the ascending colon, the transverse colon, the descending colon, the sigmoid and the rectum. The caecum and sigmoid are generally mobile and so are also at risk of twisting.

The digestive system. 

All parts of the bowel are at a risk of developing a bowel obstruction. Obstructions can be either mechanical or non-mechanical:

Mechanical obstruction

A mechanical obstruction is when the bowel becomes physically blocked from the inside, or is compressed from the outside. Common causes include:

Different causes of bowel obstruction. 

Non-mechanical obstruction

In a healthy intestine, the intestinal muscles produce a rhythmic movement, known as peristalsis, that helps move the intestine's contents along (much like a wave, or like squeezing toothpaste from a tube). A non-mechanical obstruction, also known as paralytic ileus or pseudo-obstruction, is a condition in which peristalsis does not occur. The bowel is essentially paralyzed. This is usually reversible.

Common causes may include:

Risk factors

Risk factors for bowel obstruction include:

  • Constipation;
  • Previous surgery in the abdomen or pelvis;
  • Inflammatory bowel disease, such as Crohn's disease or ulcerative colitis;
  • Cancers and/or cancer-related treatment, such as surgery and radiation therapy, and;
  • A previous case of bowel obstruction.

Signs and symptoms

With a bowel obstruction, the signs and symptoms are the result of the build-up of gases, liquids and feces within the bowel. The type of pain and other symptoms experienced will depend greatly on the location of the blockage, but the following are common:

A bowel obstruction can cause abdominal pain and cramping. 

Methods for diagnosis

Your doctor will usually perform a physical examination, feeling your abdomen for any lumps or areas of pain, and listening to your bowel sounds with a stethoscope.

Other tests may include:

Blood tests

Your doctor may want you to have blood tests done. These will likely include a full blood count and tests for inflammation, electrolyte levels and kidney function.

Scans

X-ray

An abdominal X-ray is a simple, fast and very useful test used in the diagnosis of bowel obstruction. X-rays are taken while you are lying down and sitting or standing up. Observing the air and fluid patterns in your bowel can show the presence, type and location of the obstruction.

Computerized tomography (CT) scan

Computerized tomography (CT) scans send X-ray beams from multiple angles using a machine that circles your body. A CT of the abdomen can give a detailed picture of the type, location and cause of the bowel obstruction, and can help diagnose any complications.

Barium enema

A barium enema is a bowel X-ray that uses a dye containing barium. A dye-filled tube is inserted through the anus, and releases the fluid into the colon. An X-ray is then taken of the bowel. This can help determine the presence and location of a large bowel obstruction.

Colonoscopy

A colonoscopy can be used to examine the entire length of the large bowel. A colonoscope, which is a long tube with a camera at the end, is inserted into your bowel through the anus. Air is then pumped into the bowel to allow your doctor to see it properly. This is typically performed under light sedation (anesthesia), so you remain relaxed and comfortable during the procedure. A colonoscopy may be useful in investigating certain large bowel obstructions, particularly where a volvulus is present.

The colonoscopy procedure. 

Types of treatment

Bowel obstruction is a serious medical emergency that requires immediate attention. If it is not promptly treated, you can become severely dehydrated. The wall of the bowel is thin, and can burst (perforate) if the pressure inside the bowel builds up (see 'Potential complications' below).

Immediate treatment

Bowel obstructions should be managed in a hospital, where you can be closely monitored. Your doctor will likely stabilize your condition by giving you pain-relief medications, anti-nausea medications and fluids through a drip (intravenous).

A thin tube, called a nasogastric tube, may be inserted into your stomach through the nose, to release any pressure that has built up in your stomach and to stop further vomiting and nausea. The tube is usually left in place to drain away excess fluid and gas, relieving pain, pressure and discomfort. Your will be advised to not eat any food until the condition resolves. Usually, intravenous fluid is enough to sustain your body for several days.

Further treatment depends on the underlying cause of the obstruction:

Mechanical obstruction

Some types of mechanical obstruction, such as constipation and intestinal adhesions, can be successfully treated without surgery:

Most other types of mechanical obstruction may require one of the following procedures:

Colonoscopy

Colonoscopy may be performed to untwist a volvulus and release the pressure on the affected bowel. If the volvulus is severe or too high up in the bowel, surgery will be required.

Surgery

Bowel resection surgery

Bowel resection is a type of surgery in which a part of your bowel is removed. You will be under general anesthetic during the surgery, so will not feel any pain. Once the unhealthy part of your bowel is removed, your surgeon will either staple or sew the healthy parts together.

Bowel diversion surgery

The colon is divided and rejoined on either side of the obstruction to create a 'bypass' around it. This technique is used in certain cases of bowel obstruction where the underlying cause cannot be surgically resected. The procedure is performed under general anesthesia.

Another option is to divert the bowel to an artificial opening in the abdomen (a stoma). A bag is then attached to the stoma to collect the feces. This may be a temporary or permanent solution, depending on the underlying cause. Your surgeon will discuss these options with you before your procedure.

Stent

Stents are self-expanding mesh tubes made of metal or plastic that keep the bowel open. A stent can be inserted through an obstruction or narrowing inside the bowel using colonoscopy. Stents are typically used for cancers of the large bowel, where surgery may not help, or is too risky.

Non-mechanical obstruction

Non-mechanical obstructions are generally managed by treating the underlying cause. Your doctor will generally admit you to hospital and keep you under observation. A nasogastric tube may be inserted to reduce fluid build-up and allow the bowel to rest. You may also receive fluids intravenously to prevent dehydration.

If normal bowel movements do not return, you may be given medications that cause muscle contractions. In addition, the underlying cause of the obstruction will need to be treated.

Potential complications

Bowel obstruction may be potentially fatal if the following complications occur:

Prognosis

Non-cancerous bowel obstructions, in healthy individuals, tend to have a good outcome. However, untreated complications such as gangrene or perforations can lead to the need for longer-term management, or even death.

Certain causes of bowel obstruction can increase the risk of future obstruction episodes. Your doctor can discuss if this is a possibility for you, and the measures you can take to reduce your risk.

Prevention

Prevention of intestinal obstruction will depend on the underlying cause. Some types of obstruction cannot be avoided.

You can lower your chances of constipation by drinking plenty of fluids, eating a healthy diet and exercising. Avoid developing a hernia by taking care when lifting heavy loads.

If you are suffering from a partial blockage, or are recovering from bowel surgery and are at risk of intestinal adhesions, your doctor may suggest that you take certain steps to ease your situation, such as eating smaller, more frequent meals, or avoiding certain foods (such as fatty or greasy foods, or foods that induce gas).

In some cases, your doctor may suggest that you eat a diet that is low in fiber and high in protein, to reduce the strain on your bowel and hasten healing. Since fiber is a necessary part of good nutrition, such a diet should only be followed if your doctor recommends it for your specific circumstances.

10 Most frequently asked questions (FAQs)

What is bowel obstruction?
Bowel (intestinal) obstruction occurs when you have a complete or partial blockage of your bowel. The blockage stops liquids, solids and gas from passing through your small or large intestine.
What causes bowel obstruction?
Bowel obstruction is usually due to something physically blocking your intestine. Common causes of this are scar tissue (adhesions) which form after abdominal surgery, hernias, tumors, twisting of the intestine (volvulus), telescoping (intussusception) and inflamed intestinal pouches (diverticulitis).
What are the signs and symptoms of bowel obstruction?
Signs and symptoms of bowel obstruction depend on where the blockage occurs and if it is complete or partial. Common symptoms are: colicky stomach pain and cramping, which comes and goes; abdominal fullness and swelling; inability to pass gas or have a bowel movement; constipation or diarrhea, with no appetite; nausea and vomiting, high fever; rapid pulse and breathing during cramping; rectal bleeding, and; bad breath.
Who gets bowel obstruction?
Bowel obstructions can happen to anyone, but certain conditions can raise your risk, such as: previous abdominal or pelvic surgery; inflammatory bowel disease such as Crohn's disease or ulcerative colitis; abdominal cancer, especially if a tumor has been removed and radiation therapy undergone, and; a previous history of swallowing foreign objects.
Is bowel obstruction infectious?
A bowel obstruction is not infectious, but abdominal infections (peritonitis) are a serious side effect of some types of obstruction.
Is bowel obstruction hereditary?
No, bowel obstructions are not hereditary.
Is bowel obstruction a serious condition?
Yes, all forms of bowel obstruction are a medical emergency and cannot be treated at home. Left untreated, some types of obstruction can prove fatal.
How is bowel obstruction treated?
Complete blockages will require surgery. Partial blockages can be treated by a doctor inserting a thin tube to drain away excess fluid and gas. If you have paralytic ileus (paralysis of the intestinal muscles) you may be kept under observation without any treatment, as it tends to be a temporary condition.
Will bowel obstruction happen again?
There is a slightly higher risk of having a recurring bowel obstruction with some types of this condition.
How can I prevent bowel obstruction from happening?
Most types of bowel obstruction cannot be avoided, but you can try to lead a healthier lifestyle to avoid any underlying conditions that would put you at higher risk.

Related topics

Gastroenteritis

Gastroenteritis is a common condition sometimes called ‘gastro’ or ‘stomach flu’. The main symptoms are diarrhoea, vomiting, and abdominal pain. Most people are at risk of developing it at some point in their lives.

Coeliac disease

Coeliac disease is diagnosed when the body's immune system responds inappropriately to gluten, a protein found in wheat. This results in the inner surface of the small intestine becoming inflamed. A life-long gluten free diet is the main treatment.

Colorectal cancer

Colorectal cancer is the name for cancers that arise in the large intestine or rectum. Also known as colon cancer or colorectal cancer, bowel cancer can interfere with bowel function and spread to other parts of the body, such as the liver and lungs.

Constipation

Constipation is a common condition, in which bowel movements are not regular and stools become difficult to pass. There are many causes. Treatments include drinking more fluids, a diet high in fibre, more physical activity and, when needed, medications.

About this article

Title: Bowel obstruction

Author: Karen McCloskey BHSc

First Published: 23 Sep 2014

Last reviewed: 17 Jan 2022

Category: Information on Bowel obstruction

Average rating: 4.2 out of 5 (1554 votes)

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