Intestinal Obstruction

An obstruction can occur when there is no open passageway for food or digested food waste to move through the bowel, or intestine. It can occur anywhere in the small or large intestine, and there can be a partial or complete blockage.

The bowel is basically a hollow tube that transports food and digested food waste from the stomach to the back passage (anus). There are two sections of the bowel:

• the small bowel, also called the small intestine, which is where the nutrients in the food are digested and absorbed;
• and the colon and rectum form the large bowel, or large intestine, which absorbs water from the digested food, forming it into stools (faeces) that are passed out of the back passage.

When an obstruction occurs, undigested food, liquids and digestive secretions accumulate above the blockage, the bowel section involved in the blockage becomes distended and the segment can collapse. The normal functions of the bowel wall are compromised and the distended section gets progressively worse. A completely blocked large bowel is a medical emergency.

About 20% of hospital admissions for acute abdominal pain are due to a bowel obstruction and the majority of these occur in the small intestine.

Intestinal Obstruction causes symptoms shortly after onset:

• abdominal cramps centered around the umbilicus or in the epigastrium,
• vomiting,
• and—in patients with complete obstruction—obstipation.

Patients with partial obstruction may develop diarrhea. Severe, steady pain suggests that strangulation has occurred. In the absence of strangulation, the abdomen is not tender.

Hyperactive, high-pitched peristalsis with rushes coinciding with cramps is typical. Sometimes, dilated loops of bowel are palpable. With infarction, the abdomen becomes tender and auscultation reveals a silent abdomen or minimal peristalsis. Shock and oliguria are serious signs that indicate either late simple obstruction or strangulation.

Obstruction of the large bowel usually causes milder symptoms that develop more gradually than those caused by small-bowel obstruction. Increasing constipation leads to obstipation and abdominal distention.

Vomiting may occur (usually several hours after onset of other symptoms) but is not common. Lower abdominal cramps unproductive of feces occur. Physical examination typically shows a distended abdomen with loud borborygmi.

There is no tenderness, and the rectum is usually empty. A mass corresponding to the site of an obstructing tumor may be palpable. Systemic symptoms are relatively mild and fluid and electrolyte deficits are uncommon.

The most common cause of intestinal obstruction is postsurgical adhesions. Postoperative adhesions can be the cause of acute obstruction within 4 weeks of surgery or of chronic obstruction decades later. The incidence of small-bowel obstructions (SBO) parallels the increasing number of laparotomies performed in developing countries.

Prevention of SBO may be essentially limited to decreasing the risk of adhesion formation by decreasing the number of intra-abdominal procedures (ie, laparotomies) and resultant scar formation. The incidence of chronic abdominal symptoms was significantly reduced after the use of a hyaluronic acid ̶ carboxymethylcellulose membrane (Seprafilm). However, Seprafilm placement did not provide protection against SBO.

Another commonly identified cause of SBO is an incarcerated groin hernia. Other etiologies include

• malignant tumor (20%),
• hernia (10%),
• inflammatory bowel disease (5%),
• volvulus (3%),
• and miscellaneous causes (2%).

The causes of SBO in pediatric patients include congenital atresia, pyloric stenosis, and intussusception.

Approximately 60% of mechanical large-bowel obstructions (LBOs) are caused by malignancies, 20% are caused by diverticular disease, and 5% are the result of colonic volvulus. The most common causes of adult large-bowel obstruction are as follows:

• Neoplasm (benign or malignant)
• Stricture (diverticular or ischemic)
• Volvulus (colonic, sigmoid, cecal)
• Intussusception, usually with an identifiable anatomic abnormality in adults but not in children
• Impaction or obstipation

Neoplasms and diverticular disease

Obstructions caused by tumors tend to have a gradual onset and result from tumor growth narrowing the colonic lumen.

Diverticulitis is associated with muscular hypertrophy of the colonic wall. Repetitive episodes of inflammation cause the colonic wall to become fibrotic and thickened, leading to luminal narrowing.

Volvulus

A colonic volvulus results when the colon twists on its mesentery, which impairs the venous drainage and arterial inflow. Symptoms of this condition are usually abrupt. The cecum and sigmoid colon are most commonly affected.
Volvulus typically occurs in

• elderly, debilitated individuals;
• patients living in an institutionalized setting;
• or patients with a history of chronic constipation.

Volvulus may also be seen during pregnancy, most commonly occurring in the third trimester when the gravid uterus displaces the colon.

Intussusception

Intussusception is primarily a pediatric disease; however, it is estimated that between 5% and 16% of all intussusceptions in the Western world occur in adults. Two thirds of adult intussusception cases are caused by tumors. Two main types of intussusception affect the large bowel: enterocolic and colocolic.

Enterocolic intussusceptions involve both the small bowel and the large bowel. These are composed of either ileocolic intussusceptions or ileocecal intussusceptions, depending on where the lead point is located.

Colocolic intussusceptions involve only the colon. They are classified as either colocolic or sigmoidorectal intussusceptions.

Acute colonic pseudo-obstruction/Ogilvie syndrome

Acute colonic pseudo-obstruction (ACPO), or Ogilvie syndrome, has many etiologies. ACPO is a functional obstruction; it is typically seen in elderly or debilitated patients who are hospitalized with severe medical or traumatic illnesses.

Medications that decrease intestinal motility are also associated with this disorder. The most common predisposing conditions are

• operative and nonoperative trauma (11%),
• infections (10%),
• cardiac disease (10-18%).

Making diagnosis of intestinal obstruction is done by:

• blood tests,
• X-rays of the abdomen,
• CT scanning,
• and/or ultrasound.

If a mass is identified, biopsy may determine the nature of the mass.

Radiological signs of bowel obstruction include bowel distension and the presence of multiple (more than six) gas-fluid levels on supine and erect abdominal radiographs.

Contrast enema or small bowel series or CT scan can be used to define the level of obstruction, whether the obstruction is partial or complete, and to help define the cause of the obstruction.

The appearance of water-soluble contrast in the cecum on an abdominal radiograph within 24 hours of oral administration predicts resolution of an adhesive small bowel obstruction with a pooled sensitivity of 96% and specificity of 96%.

Colonoscopy, small bowel investigation with ingested camera or push endoscopy, and laparoscopy are other diagnostic options.

The treatment will depend on the cause of intestinal obstruction. For example, in a case of paralytic ileus, treatment may involve inserting a flexible tube (nasogastric tube) down the throat to drain fluids from the stomach as well as correcting fluid and electrolyte imbalances.

In most cases a partial blockage will not require surgery, but a complete blockage will. The type of surgery will depend on the type of blockage and its location.

A laparotomy

Where an incision is made into the abdomen while under general anaesthesia, may be performed to search for the cause of an obstruction and/or to remove or manage it.

Laparoscopy, or keyhole surgery

In which a laparoscope (a small tube with a light and camera on the end) is inserted into a small incision, may be an option for treating a small bowel obstruction or removing adhesions.

Endoscopic stenting

Where a self-expanding stent is inserted to help keep the passageway open, may be considered in the elderly and in palliative care of cancer patients.

A sigmoidoscopy or colonoscopy

Involves inserting a thin flexible tube with a small camera and light attached on one end through the rectum into the bowel, along with a flatus tube (a long rubber tube), to decompress and untwist the bowel.

During the operation the specialist may remove only the cause of the blockage, or a part of the bowel may need removing too, with the ends of the remaining sections stitched together. However, in severe cases a colostomy or ileostomy may be necessary, where a stoma (a type of opening) is made in the abdomen so that your faeces can pass out of the stoma into a plastic bag.

Medication such as corticosteroids, opioid painkillers, antispasmodics or antiemetics may be prescribed to control the symptoms when a blockage occurs in a patient who is not well enough to cope with surgery.

You may be able to prevent some forms of intestinal obstruction by modifying your diet and lifestyle. For example:

• To help prevent colorectal cancer, eat a balanced diet low in fat with plenty of vegetables and fruits, don’t smoke, and see your doctor for colorectal cancer screening once a year after age 50.

• To help prevent hernias, avoid heavy lifting, which increases pressure inside the abdomen and may force a section of intestine to protrude through a vulnerable area of your abdominal wall. If you develop an abnormal lump under the skin of your abdomen, especially near your groin or near a surgical scar, contact your doctor.

• There is no proven way to prevent obstruction caused by diverticular disease, but some doctors believe that people with diverticular disease should follow a high-fiber diet and avoid foods that may become lodged in the diverticula, such as seeds and popcorn.

Several alternative remedies exist for intestinal obstruction.

In order to prevent bowel obstruction, one must eat fibrous foods, especially green leafy vegetables and fresh fruits and juices and drink lots of water every day.

Working out everyday for about 30 minutes also keeps the bowel clean.

Avoid excessive sugar, processed, oily and starchy food. White flour, especially, is bad for the bowel. Also, don’t sleep for at least two hours after dinner. Taking a stroll after eating also helps digest food.

If you embark on an all-fruits and juices diet once a week, it will be good for cleansing the colon.

There are many home remedies that will keep your intestines clean and free from obstruction. The easiest one is eating an apple every morning. The bowel obstruction will be cured in a few days.

Another effective remedy is drinking a cup of lemon tea with honey added to it. You can also drink a glass of boiled and cooled water with honey in it every night before going to bed.

Drinking a glassful orange juice every morning will also ensure that all the accumulated waste will be expelled from the intestines.

Mixing one teaspoon of mint juice and lime juice each with a small amount of ginger juice and black salt is a good remedy too.

There are several risks and complications associated with intestinal obstruction.

Complications may include or may lead to:

• Electrolyte (blood chemical and mineral) imbalances
• Dehydration
• Hole (perforation) in the intestine
• Infection
• Jaundice (yellowing of the skin and eyes)

If the obstruction blocks the blood supply to the intestine, it may cause infection and tissue death (gangrene). Risks for tissue death are related to the cause of the blockage and how long it has been present. Hernias, volvulus, and intussusception carry a higher gangrene risk.

In a newborn, paralytic ileus that destroys the bowel wall (necrotizing enterocolitis) is a life-threatening condition. It may lead to blood and lung infections.