Crohn's Disease

views updated Jun 08 2018

Crohn's disease

Definition

Crohn's disease is a type of inflammatory bowel disease (IBD), resulting in swelling and dysfunction of the intestinal tract.

Description

Crohn's disease involves swelling, redness, and loss of function of the intestine, especially the small intestine. There is evidence that this inflammation is caused by a misfire of the immune system, which attacks the body itself instead of attacking foreign invaders, such as viruses or bacteria. The inflammation of Crohn's disease most commonly occurs in the last part of the ileum (a section of the small intestine), and often includes the large intestine (the colon). However, inflammation may also occur in other areas of the gastrointestinal tract, including the mouth, esophagus, or stomach. Crohn's disease differs from ulcerative colitis, the other major type of IBD, in two important ways:

  • The inflammation of Crohn's disease may be discontinuous, meaning that areas of involvement in the intestine may be separated by normal, unaffected segments of intestine. The affected areas are called "regional enteritis," while the normal areas are called "skip areas."
  • The inflammation of Crohn's disease affects all the layers of the intestinal wall, while ulcerative colitis affects only the lining of the intestine.

Also, ulcerative colitis does not usually involve the small intestine; in rare cases it involves the terminal ileum (so-called "backwash" ileitis).

In addition to inflammation, Crohn's disease causes ulcerations, or irritated pits, in the intestinal wall. These pits occur because the inflammation has made areas of tissue shed away.

While Crohn's disease and ulcerative colitis are similar, they are also very different. Although it can be difficult to determine whether a patient has Crohn's disease or ulcerative colitis, it is important to make every effort to distinguish between these two diseases. Because the long-term complications of the diseases are different, treatment will depend on careful diagnosis of the specific IBD present.

Crohn's disease may be diagnosed at any age, although most diagnoses are made between the ages of 1535. About 2040 people out of 10,000 suffer from this disorder, with men and women having an equal chance of being stricken. Caucasians are more frequently affected than other racial groups, and people of Jewish origin appear three to six times more likely to suffer from IBD. IBD runs in families; an IBD patient has a 20% chance of having other relatives who are fellow sufferers.

Crohn's disease is a chronic disorder. While the symptoms can be improved, there is no known cure for the underlying disease.

Causes & symptoms

The cause of Crohn's disease is unknown. No infectious agent (virus, bacteria, or fungi) has been identified as the etiologic agent. Still, some researchers have theorized that some type of infection may have originally been responsible for triggering the immune system, resulting

in the continuing and out-of-control cycle of inflammation that occurs in Crohn's disease. Other evidence for a disorder of the immune system includes the high incidence of other immune disorders that may occur along with Crohn's disease.

The first symptoms of Crohn's disease may include diarrhea, fever , abdominal pain , inability to eat, weight loss, and fatigue . Some patients experience severe pain that mimics appendicitis . It is rare, however, for patients to notice blood in their bowel movements. Because Crohn's disease severely limits the ability of the affected intestine to absorb the nutrients from food, a patient with Crohn's disease can have signs of malnutrition, depending on the amount of intestine affected and the duration of the disease.

The combination of severe inflammation, ulceration, and scarring that occurs in Crohn's disease can result in serious complications, including obstruction, abscess formation, and fistula formation.

An obstruction is a blockage in the intestine. This obstruction prevents the intestinal contents from passing beyond the point of the blockage. The intestinal contents "back up," resulting in constipation, vomiting , and intense pain. Although rare in Crohn's disease (because of the increased thickness of the intestinal wall due to swelling and scarring), a severe bowel obstruction can result in an intestinal wall perforation (a hole in the intestine). Such a hole in the intestinal wall would allow the intestinal contents, usually containing bacteria, to enter the abdomen. This complication could result in a severe, life-threatening infection.

Abcess formation is the development of a walledoff pocket of infection. A patient with an abscess will have bouts of fever, increased abdominal pain, and may have a lump or mass that can be felt through the wall of the abdomen.

Fistula formation is the formation of abnormal channels between tissues. These channels may connect one area of the intestine to another neighboring section of intestine. Fistulas may join an area of the intestine to the vagina or bladder, or they may drain an area of the intestine through the skin. Abscesses and fistulas commonly affect the area around the anus and rectum (the very last portions of the colon allowing waste to leave the body). These abnormal connections allow the bacteria that normally live in the intestine to enter other areas of the body, causing potentially serious infections .

Patients suffering from Crohn's disease also have a significant chance of experiencing other disorders. Some of these may relate specifically to the intestinal disease, and others appear to have some relationship to the imbalanced immune system. The faulty absorption state of the bowel can result in gallstones and kidney stones . Inflamed areas in the abdomen may press on the tube that drains urine from the kidney to the bladder (the ureter). Ureter compression can make urine back up into the kidney, enlarge the ureter and kidney, and can potentially lead to kidney damage. Patients with Crohn's disease also frequently suffer from:

  • arthritis (inflammation of the joints)
  • spondylitis (inflammation of the vertebrae, the bones of the spine)
  • ulcers of the mouth and skin
  • painful, red bumps on the skin
  • inflammation of several eye areas
  • inflammation of the liver, gallbladder, and/or the channels (ducts) that carry bile between and within the liver, gallbladder, and intestine

The chance of developing cancer of the intestine is greater than normal among patients with Crohn's disease, although this chance is not as high as among those patients with ulcerative colitis.

Diagnosis

Diagnosis is first suspected based upon a patient's symptoms. Blood tests may reveal an increase in certain types of white blood cells, an indication that some type of inflammation or infection is occurring in the body. The blood tests may also reveal anemia and other signs of malnutrition due to malabsorption (low blood protein; variations in the amount of calcium, potassium , and magnesium present in the blood; changes in certain markers of liver function). Stool samples may be examined to make sure that no infectious agent is causing the diarrhea, and to see if the waste contains blood.

A colonoscopy may be performed to view the interior of the colon. During colonoscopy, a doctor passes a flexible tube with a tiny, fiber-optic camera device (an endoscope) through the rectum and into the colon. The doctor can then carefully examine the lining of the intestine for signs of inflammation and ulceration that might suggest Crohn's disease. A tissue sample (a biopsy) of the intestine can also be taken through the endoscope to examine under a microscope for evidence of Crohn's disease.

Both an upper and lower GI (gastrointestinal) x ray series can be helpful in determining how much of the intestine is involved in the disease. In the upper GI (also called a small bowel series), the patient drinks a chalky solution called barium, which acts as a contrast agent to illuminate the gastrointestinal tract on x-ray film. After the barium is ingested, x rays are taken at specific time intervals as the barium passes through the stomach and into and through the small intestine. The lower GI series provides an x-ray study of the large intestine. The patient is given an enema containing barium, and in some cases, air is also pumped into the rectum to provide a clearer view of the large intestine. This is called a double-contrast barium enema.

Treatment

Crohn's disease is a chronic, often progressive, illness. A correct diagnosis and appropriate treatment with anti-inflammatory medications is critical to controlling the disease.

Some Crohn's patients find that certain foods are hard to digest, including milk, large quantities of fiber, and spicy foods. Dietary adjustments are usually necessary to minimize pain, diarrhea, and other symptoms.

Acupuncture and guided imagery may be useful tools in treating any pain associated with Crohn's disease. Acupuncture involves the placement of thin needles into the skin at targeted locations on the body known as acupoints in order to harmonize the energy flow within the human body. To treat chronic pain, such as that involved with Crohn's disease, an acupuncturist will frequently place the acupuncture needles along what is known as the large intestine meridian.

Guided imagery involves creating a visual mental image of one's pain in one's mind. Once the pain can be visualized, the patient can adjust the image to make it more pleasing, and thus, more manageable.

Several herbal remedies are also available to lessen pain symptoms and promote relaxation and healing. These include peppermint oil, slippery elm (Ulmus rubra ), marsh mallow (Althaea oficinalis ), and Chinese herbs. However, Crohn's patients should consult with their healthcare professional before taking them. Depending on the preparation and the type of herb, these remedies may aggravate the digestive tract or interact with any prescription drugs that are being taken to control the inflammation of Crohn's disease.

Allopathic treatment

Treatments for Crohn's disease try to reduce the underlying inflammation, the resulting malabsorption/malnutrition, the uncomfortable symptoms of crampy abdominal pain and diarrhea, and any possible complications (obstruction, abscesses, and fistulas).

Inflammation can be treated with a drug called sulfasalazine. Sulfasalazine is made up of two parts. One part is related to the sulfa antibiotics; the other part is a form of the anti-inflammatory chemical, salicylic acid. Sulfasalazine is not well-absorbed from the intestine, so it stays mostly within the intestine, where it is broken down into its components. It is believed that the salicylic acid component actively treats Crohn's disease by fighting inflammation. Some patients do not respond to sulfasalazine, particularly those with more severe disease. These patients require steroid medications (such as prednisone). Steroids, however, must be used carefully to avoid the complications of these drugs, including increased risk of infection and weakening of bones (osteoporosis )

In 2001, the Food and Drug Administration (FDA) approved use of budesonide capsules for mild and moderate cases of Crohn's disease involving the small and large intestines. Although a steroid, the makeup of budesonide allows the drug to release into the intestines, where it can be mostly metabolized. As a result, less of the drug enters the patient's system, meaning fewer undesirable side effects. Some potent immunosuppressive drugs that interfere with the products of the immune system and hopefully decrease inflammation may be used for those patients who do not improve on steroids.

Serious cases of malabsorption/malnutrition may need to be treated by providing nutritional supplements. These supplements must be in a form that can be absorbed from the damaged, inflamed intestine. When patients are suffering from an obstruction, or during periods of time when symptoms of the disease are at their worst, they may need to drink specially formulated, high-calorie liquid supplements. Those patients who are severely ill may need to receive their nutrition through a needle inserted intravenously.

A number of medications are available to help decrease the cramping and pain associated with Crohn's disease. These include loperamide, tincture of opium, and codeine. Some fiber preparations (methylcellulose or psyllium ) may be helpful, although some patients do not tolerate them well.

The first step in treating an obstruction involves general attempts to decrease inflammation with sulfasalazine, steroids, or immunosuppressive drugs. A patient with a severe obstruction will have to stop taking all food and drink by mouth, allowing the bowel to "rest." Abscesses and other infections will require antibiotics. Surgery may be required to repair an obstruction that does not resolve on its own, to remove an abscess, or to repair a fistula. Such surgery may involve the removal of a section of the small intestine. In extremely severe cases of Crohn's disease of the colon that do not respond to treatment, a patient may need to have the entire large intestine removed (an operation called a colectomy). In this case, a piece of the remaining small intestine is pulled through an opening in the abdomen. This bit of intestine is fashioned surgically to allow a special bag to be placed over it. This bag catches the body's waste, which no longer can be passed through the large intestine and out of the anus. This opening, which will remain in place for life, is called an ileostomy. However, as an alternative to ileostomy, small intestines are now often shaped into substitute rectal pouches, and the patient may not always need the ileostomy.

Expected results

Crohn's disease is a lifelong illness. The severity of the disease can vary, and a patient can experience periods of time when the disease is not active and he or she is symptom free. However, the complications and risks of Crohn's disease tend to increase over time. Well over 60% of all patients with Crohn's disease will require surgery, and about half of these patients will require more than one operation over time. About 510% of all Crohn's patients will die of their disease, primarily due to massive infection.

Prevention

Crohn's disease is a chronic, lifelong disorder. However, a study published in the New England Journal of Medicine in June 2000 reported that methotrexate (a chemotherapy drug) was found to prevent relapse episodes in a clinical trial of Crohn's patients. The study also found that human growth hormone was useful in reducing symptoms of the disease.

Resources

BOOKS

Glickman, Robert. "Inflammatory Bowel Disease: Ulcerative Colitis and Crohn's Disease." In Harrison's Principles of Internal Medicine. Anthony S. Fauci et al., eds. New York: McGraw-Hill, 1998.

Long, James W. The Essential Guide to Chronic Illness. New York: HarperPerennial, 1997.

Saibil, Fred. Crohn's Disease and Ulcerative Colitis. Buffalo, NY: Firefly Books, 1997.

PERIODICALS

Peppercorn, Mark A., and Susannah K. Gordon. "Making Sense of a Mystery Ailment: Inflammatory Bowel disease."Harvard Health Letter 22, no. 2 (December 1996): 4+.

Sachar, David. "Maintenance Strategies in Crohn's Disease." Hospital Practice 31, no. 1 (January 15, 1996): 99+.

Karpa, Kelly Dowhower. "Crohn's disease patients find new relief from old drug."Drug Topics 145, no. 21 (November 5, 2001): 16;.

ORGANIZATIONS

Crohn's & Colitis Foundation of America, Inc. 386 Park Avenue South, 17th Floor, New York, NY 10016-8804. (800) 932-2423.

Paula Ford-Martin

Teresa G. Odle

Crohn's Disease

views updated May 23 2018

Crohn's Disease

Definition

Crohn's disease is a type of inflammatory bowel disease (IBD), resulting in swelling and dysfunction of the intestinal tract.

Description

Crohn's disease involves inflammation of the intestine, especially the small intestine. Inflammation refers to swelling, redness, and loss of normal function. There is evidence that the inflammation is caused by various products of the immune system that attack the body itself instead of helpfully attacking a foreign invader (a virus or bacteria, for example). The inflammation of Crohn's disease most commonly affects the last part of the ileum (a section of the small intestine), and often includes the large intestine (the colon). However, inflammation may also occur in other areas of the gastrointestinal tract, affecting the mouth, esophagus, or stomach. Crohn's disease differs from ulcerative colitis, the other major type of IBD, in two important ways:

  • The inflammation of Crohn's disease may be discontinuous, meaning that areas of involvement in the intestine may be separated by normal, unaffected segments of intestine. The affected areas are called "regional enteritis," while the normal areas are called "skip areas."
  • The inflammation of Crohn's disease affects all the layers of the intestinal wall, while ulcerative colitis affects only the lining of the intestine.

Also, ulcerative colitis does not usually involve the small intestine; in rare cases, it involves the terminal ileum (so-called "backwash" ileitis).

In addition to inflammation, Crohn's disease causes ulcerations, or irritated pits in the intestinal wall. These pits occur because the inflammation has made areas of tissue shed.

Crohn's disease may be diagnosed at any age, although most diagnoses are made between the ages 15 to 35. About 0.02-0.04% of the population suffers from this disorder, with men and women having an equal chance of being stricken. Whites are more frequently affected than other racial groups, and people of Jewish origin are between three and six times more likely to suffer from IBD. IBD runs in families; an IBD patient has a 20% chance of having other relatives who are fellow sufferers.

Crohn's disease is a chronic disorder. While the symptoms can be improved, a patient will not be completely cured of the underlying disease.

Causes and symptoms

The cause of Crohn's disease is unknown. No infectious agent (virus, bacteria, or fungi) has been identified as the cause of Crohn's disease. Still, some researchers have theorized that some type of infection may have originally been responsible for triggering the immune system, resulting in the continuing and out-of-control cycle of inflammation that occurs in Crohn's disease. Other evidence for a disorder of the immune system includes the high incidence of other immune disorders that may occur along with Crohn's disease.

The first symptoms of Crohn's disease include diarrhea, fever, abdominal pain, inability to eat, weight loss, and fatigue. Some patients have severe pain that mimics appendicitis. It is rare, however, for patients to notice blood in their bowel movements. Because Crohn's disease severely limits the ability of the affected intestine to absorb the nutrients from food, a patient with Crohn's disease can have signs of malnutrition, depending on the amount of intestine affected and the duration of the disease.

The combination of severe inflammation, ulceration, and scarring that occurs in Crohn's disease can result in serious complications, including obstruction, abscess formation, and fistula formation.

An obstruction is a blockage in the intestine. This obstruction prevents the intestinal contents from passing beyond the point of the blockage. The intestinal contents "back up," resulting in constipation, vomiting, and intense pain. Although rare in Crohn's disease (because of the increased thickness of the intestinal wall due to swelling and scarring), a severe bowel obstruction can result in an intestinal wall perforation (a hole in the intestine). Such a hole in the intestinal wall would allow the intestinal contents, usually containing bacteria, to enter the abdomen. This complication could result in a severe, life-threatening infection.

Abcess formation is the development of a walled-off pocket of infection. A patient with an abscess will have bouts of fever, increased abdominal pain, and may have a lump or mass that can be felt through the wall of the abdomen.

Fistula formation is the formation of abnormal channels. These channels may connect one area of the intestine to another neighboring section of intestine. Fistulas may join an area of the intestine to the vagina or bladder, or they may drain an area of the intestine through the skin. Abscesses and fistulas commonly affect the area around the anus and rectum (the very last portions of the colon allowing waste to leave the body). These abnormal connections allow the bacteria that normally live in the intestine to enter other areas of the body, causing potentially serious infections.

Patients suffering from Crohn's disease also have a significant chance of experiencing other disorders. Some of these may relate specifically to the intestinal disease, and others appear to have some relationship to the imbalanced immune system. The faulty absorption state of the bowel can result in gallstones and kidney stones. Inflamed areas in the abdomen may press on the tube that drains urine from the kidney to the bladder (the ureter). Ureter compression can make urine back up into the kidney, enlarge the ureter and kidney, and can potentially lead to kidney damage. Patients with Crohn's disease also frequently suffer from:

  • arthritis (inflammation of the joints)
  • spondylitis (inflammation of the vertebrae, the bones of the spine)
  • ulcers of the mouth and skin
  • painful, red bumps on the skin
  • inflammation of several eye areas
  • inflammation of the liver, gallbladder, and/or the channels (ducts) that carry bile between and within the liver, gallbladder, and intestine

The chance of developing cancer of the intestine is greater than normal among patients with Crohn's disease, although this chance is not as high as among those patients with ulcerative colitis.

Diagnosis

Diagnosis is first suspected based on a patient's symptoms. Blood tests may reveal an increase in certain types of white blood cells, an indication that some type of inflammation is occurring in the body. The blood tests may also reveal anemia and other signs of malnutrition due to malabsorption (low blood protein; variations in the amount of calcium, potassium, and magnesium present in the blood; changes in certain markers of liver function). Stool samples may be examined to make sure that no infectious agent is causing the diarrhea, and to see if the waste contains blood.

During an endoscopic exam, a doctor passes a flexible tube with a tiny, fiber-optic camera device through the rectum and into the colon. The doctor can then carefully examine the lining of the intestine for signs of inflammation and ulceration that might suggest Crohn's disease. A tiny sample (a biopsy) of the intestine can also be taken through the endoscope, and the tissue will be examined under a microscope for evidence of Crohn's disease.

X rays can be helpful for diagnosis, and also for determining how much of the intestine is involved in the disease. For these x rays, the patient must either drink a chalky solution containing barium, or receive a barium enema (a solution that is administered through the rectum). Barium helps to "light up" the intestine, allowing more detail to be seen on the resulting x rays.

While Crohn's disease and ulcerative colitis are similar, they are also very different. Although it can be difficult to determine whether a patient has Crohn's disease or ulcerative colitis, it is important to make every effort to distinguish between these two diseases. Because the long-term complications of the diseases are different, treatment will depend on careful diagnosis of the specific IBD present.

Treatment

Treatments for Crohn's disease try to reduce the underlying inflammation, the resulting malabsorption/malnutrition, the uncomfortable symptoms of crampy abdominal pain and diarrhea, and the possible complications (obstructions, abscesses, and fistulas).

Inflammation can be treated with a drug called sulfasalazine. Sulfasalazine is made up of two parts. One part is related to the sulfa antibiotics ; the other part is a form of the anti-inflammatory chemical, salicylic acid (related to aspirin ). Sulfasalazine is not well absorbed from the intestine, so it stays mostly within the intestine, where it is broken down into its components. It is believed that the salicylic acid component actively treats Crohn's disease by fighting inflammation. Some patients do not respond to sulfasalazine, and require steroid medications (such as prednisone). Steroids, however, must be used carefully to avoid the complications of these drugs, including increased risk of infection and weakening of bones (osteoporosis ). Some very potent immunosuppressive drugs, which interfere with the products of the immune system and can hopefully decrease inflammation, may be used for those patients who do not improve on steroids.

A new drug called infliximab (Remicade) appears to be a powerful treatment for Crohn's disease, particularly for patients who have not responded well to other forms of treatment. Infliximab is administered through infusion, and consists of a monoclonal antibody that interferes with the inflammatory process mediated by tumor necrosis factor-alpha (TNF-a). Patients taking infliximab seem to be able to decrease their use of steroid medications, and require fewer surgical interventions. Furthermore, infliximab is the first medication approved for treating fistulas. Unfortunately, infliximab can only be used on a short-term basis, because its interference with TNF-a activity can also predispose patients to serious infection. More research is needed to try to harness the benefits of infliximab, while avoiding the potential complications.

Serious cases of malabsorption/malnutrition may need to be treated by providing nutritional supplements. These supplements must be in a form that can be absorbed from the damaged, inflamed intestine. Some patients find that certain foods are hard to digest, including milk, large quantities of fiber, and spicy foods. When patients are suffering from an obstruction, or during periods of time when symptoms of the disease are at their worst, they may need to drink specially formulated, high-calorie liquid supplements. Those patients who are severely ill may need to receive their nutrition through a needle inserted in a vein (intravenously), or even by a tiny tube (a catheter) inserted directly into a major vein in the chest.

A number of medications are available to help decrease the cramping and pain associated with Crohn's disease. These include loperamide, tincture of opium, and codeine. Some fiber preparations (methylcellulose or psyllium) may be helpful, although some patients do not tolerate them well.

The first step in treating an obstruction involves general attempts to decrease inflammation with sulfasalazine, steroids, or immunosuppressive drugs. A patient with a severe obstruction will have to stop taking all food and drink by mouth, allowing the bowel to "rest." Abscesses and other infections will require antibiotics. Surgery may be required to repair an obstruction that does not resolve on its own, to remove an abscess, or to repair a fistula. Such surgery may involve the removal of a section of the intestine. In extremely severe cases of Crohn's disease that do not respond to treatment, a patient may need to have the entire large intestine removed (an operation called a colectomy). In this case, a piece of the remaining small intestine is pulled through an opening in the abdomen. This bit of intestine is fashioned surgically to allow a special bag to be placed over it. This bag catches the body's waste, which no longer can be passed through the large intestine and out of the anus. This opening, which will remain in place for life, is called an ileostomy.

Prognosis

Crohn's disease is a life-long illness. The severity of the disease can vary, and a patient can experience periods of time when the disease is not active and he or she is symptom free. However, the complications and risks of Crohn's disease tend to increase over time. Well over 60% of all patients with Crohn's disease will require surgery, and about half of these patients will require more than one operation over time. About 5-10% of all Crohn's patients will die of their disease, primarily due to massive infection.

KEY TERMS

Abscess A walled-off pocket of pus caused by infection.

Endoscope A medical instrument that can be passed into an area of the body (the bladder or intestine, for example) to allow examination of that area. The endoscope usually has a fiber-optic camera that allows a greatly magnified image to be shown on a television screen viewed by the operator. Many endoscopes also allow the operator to retrieve a small sample (biopsy) of the area being examined, to more closely view the tissue under a microscope.

Fistule An abnormal channel that creates an open passageway between two structures that do not normally connect.

Gastrointestinal tract The entire length of the digestive system, running from the stomach, through the small intestine, large intestine, and out the rectum and anus.

Immune system The body system responsible for producing various cells and chemicals that fight infection by viruses, bacteria, fungi, and other foreign invaders. In autoimmune disease, these cells and chemicals turn against the body itself.

Inflammation The result of the body's attempts to fight off and wall off an area that is infected. Inflammation results in the classic signs of redness, heat, swelling, and loss of function.

Obstruction A blockage.

Ulceration A pitted area or break in the continuity of a surface such as skin or mucous membrane.

Crohn's Disease

views updated May 21 2018

Crohn's Disease

Definition

Crohn's disease is a type of inflammatory bowel disease (IBD) caused by inflammation along any portion of the alimentary canal (the mouth to the anus).

Description

Although Crohn's disease may involve any part of the alimentary canal, it most commonly affects the small intestine. There is evidence that the inflammation is an autoimmune response—when products of the immune system attack the body itself instead of attacking a foreign substance such as a virus or bacteria.

The part of the small intestine most commonly affected is the last part of the ileum, also known as the terminal ileum. The colon (large intestine ) is less commonly involved. Inflammation may also occur in other areas of the alimentary canal, less frequently affecting the mouth, esophagus, or stomach.

Crohn's disease differs from ulcerative colitis, the other major type of IBD, in the following ways:

  • The inflammation of Crohn's disease may be discontinuous, meaning that areas of involvement in the intestine may be separated by normal, unaffected segments of intestine. The affected areas are called "regional enteritis," while the normal areas are called "skip areas."
  • The inflammation of Crohn's disease is transmural; this means it affects all the layers of the intestinal wall, while ulcerative colitis affects only the lining of the intestine.
  • Ulcerative colitis does not usually involve the small intestine; in rare cases it involves the terminal ileum (so-called "backwash" ileitis).

In addition to inflammation, Crohn's disease causes ulceration. These ulcers occur because the inflammation has caused areas of tissue destruction.

Crohn's disease may be diagnosed at any age, although most diagnoses are made between the ages 15-35. About 0.02-0.04% of the population suffers from this disorder. It affects equal numbers of males and females. Whites are more frequently affected than other racial groups, and people of Jewish origin are between three and six times more likely to suffer from IBD. IBD runs in families; an IBD patient has a 20% chance of having other relatives who are fellow sufferers.

Crohn's disease is a chronic disorder. Though symptoms can be effectively controlled, patients are not completely cured of the underlying disease.

Causes and symptoms

The cause of Crohn's disease is unknown. No infectious agent has been positively identified as the cause of Crohn's disease. Some researchers have theorized that a certain bacterium may have originally been responsible for triggering the immune system, resulting in the abnormal activation of the immune system in the intestines that occurs in Crohn's disease.

Symptoms of Crohn's disease depend on which section of the alimentary canal is affected. Symptoms may include diarrhea, fever, abdominal pain, loss of appetite, weight loss, and fatigue. Some patients experience severe pain that mimics appendicitis. Unlike patients with ulcerative colitis, it is rare for patients with Crohn's disease to notice blood in their bowel movements. Because Crohn's disease severely limits the ability of the affected intestine to absorb the nutrients from food, a patient may have signs of malnutrition, depending on the amount of intestine affected and the duration of the disease.

The combination of severe inflammation, ulceration, and scarring that occurs in Crohn's disease can result in serious complications, including intestinal obstruction, intra-abdominal abscess formation, and fistula formation.

An obstruction is a mechanical blockage in the intestine. This obstruction, called a stricture, prevents the intestinal contents from passing beyond the point of the blockage. The intestinal contents "back up," resulting in constipation, vomiting, and intense pain. Although rare in Crohn's disease (because of the increased thickness of the intestinal wall due to swelling and scarring), severe bowel obstruction can result in an intestinal wall perforation (a hole in the intestine). A hole in the intestinal wall would allow the intestinal contents, containing bacteria, to enter the abdominal cavity, causing a severe, life-threatening infection known as peritonitis.

Abscess formation is the development of a walled-off pocket of pus. A patient with an abscess in the abdomen will have fever, abdominal pain, and may have a lump or mass that can be palpated (felt) through the wall of the abdomen.

Fistula formation is the formation of abnormal channels. These channels may connect one loop of the intestine to a neighboring section of intestine. Fistulas may connect an area of the intestine to the vagina or urinary bladder, or may drain an area of the intestine through the skin. Abscesses and fistulas commonly affect the area around the anus and rectum. These abnormal connections allow the bacteria normally present in the intestine to enter other areas of the body, causing potentially serious infections.

Patients suffering from Crohn's disease are at increased risk of other disorders. Some of these may relate specifically to the intestinal disease, and others appear to have some relationship to the compromised immune system. The faulty absorption of the bowel can result in gallstones and kidney stones. Inflamed areas in the abdomen may compress and block the ureter (the tube that drains urine from the kidney to the bladder) causing failure of the kidney on the affected side. Patients with Crohn's disease also frequently suffer from extraintestinal manifestations such as:

  • arthritis (inflammation of the joints)
  • spondylitis (inflammation of the vertebrae, the bones of the spine)
  • ulcers of the mouth and skin
  • erythema nodosum (painful, red bumps on the skin)
  • inflammation of several eye areas
  • inflammation of the liver, gallbladder, and/or the ducts that carry bile between and within the liver, gallbladder, and intestine

The risk of developing cancer of the intestine is greater than average among patients with Crohn's disease, although the cancer risk is not as high as it is for patients with ulcerative colitis.

Diagnosis

Diagnosis is first suspected based on a patient's symptoms. Blood tests may reveal an increase in white blood cells, an indication that some type of inflammation is occurring in the body. The blood tests may also reveal anemia and other signs of malnutrition due to malabsorption, such as low blood protein; low calcium, potassium, and magnesium present in the blood; and indications of liver inflammation. Stool samples may be examined to rule out various infectious agents, and to see if the stool contains blood.

During a colonoscopic exam, a physician passes a flexible tube with a tiny, fiber-optic camera (called an endoscope ) through the rectum and into the colon. The physician carefully examines the lining of the intestine for signs of inflammation and ulceration that might suggest Crohn's disease. A biopsy of the intestine can also be taken through the colonoscope, and the tissue will be examined under a microscope for evidence of Crohn's disease.

X rays can be helpful for diagnosis, and to determine how much of the intestine is involved in the disease. For these x rays, the patient must either drink a chalky solution containing barium, or receive a barium enema. Barium helps to "light up" the intestine, allowing more detail to be seen on the resulting x rays.

Crohn's disease and ulcerative colitis are similar, but they are distinct conditions. Although it may be difficult to determine whether a patient has Crohn's disease or ulcerative colitis, it is important to make every effort to distinguish between these two diseases because the long-term complications of the diseases are different, as is the treatment.

Treatment

Treatment for Crohn's disease aims to reduce the underlying inflammation, the resulting malabsorption/malnutrition, and relieve symptoms of abdominal pain and diarrhea. Treatment is also intended to prevent potential complications such as obstructions, abscesses, and fistulas.

Inflammation can be treated with a drug called sulfasalazine. Sulfasalazine is in part related to the sulfa antibiotics; its other component is a form of the anti-inflammatory chemical, salicylic acid (related to aspirin). Sulfasalazine is not well absorbed from the intestine, so it remains largely within the intestine, where it is broken down into its components. It is believed that the salicylic acid component actively treats Crohn's disease by fighting inflammation. Some patients do not respond to sulfasalazine and require corticosteroids such as prednisone. Corticosteroids, however, must be used carefully to avoid the various complications of these drugs, including an increased risk of infection and osteoporosis (weakening of the bones).

Patients with intra-abdominal abscesses or those with disease in the large bowel or ileum may be given antibiotics such as metronidazole or ciprofloxacin. Potent immunosuppressive drugs, such as 6-mercaptopurine, azathioprine, cyclosporine, and infliximab, which block the immune system and thereby reduce inflammation, may be prescribed for patients who do not respond to corticosteroids.

Serious cases of malabsorption/malnutrition may require treatment with nutritional supplements. These supplements must be in a form that can be absorbed from the damaged, inflamed intestine. Some patients find that certain foods are hard to digest, including milk, large quantities of fiber, and spicy foods. When patients are suffering from an obstruction, or during periods of time when symptoms of the disease are at their worst, they may need to drink specially formulated, high-calorie liquid supplements. Those patients who are severely ill may need total parenteral nutrition (TPN). TPN patients receive their nutrition intravenously, or through a catheter inserted directly into a major vein in the chest.

A number of medications are available to help decrease the cramping and pain associated with Crohn's disease. These include loperamide, tincture of opium, and codeine. Fiber preparations (methylcellulose or psyllium) are helpful for some patients; others do not tolerate them well.

The first step in treating an obstruction involves general efforts to decrease inflammation with sulfasalazine, steroids, or immunosuppressive drugs. A patient with a severe obstruction is given no food or drink by mouth, allowing the bowel to "rest." Abscesses and other infections require antibiotics. Surgery may be required to repair an obstruction that does not resolve on its own, to drain an abscess, or to repair a fistula. Such surgery may involve the resection (removal) of the diseased length of the intestine.

In extremely severe cases of Crohn's disease that do not respond to treatment, patients may require a colostomy. In this procedure, a piece of the remaining small intestine is pulled through an opening in the abdomen. This segment of intestine is fashioned surgically to allow a special bag to be placed over it. This bag collects the stool, which can no longer pass through the large intestine and out of the anus.

KEY TERMS

Abscess— A walled-off pocket of pus caused by infection.

Endoscope— An instrument that can be passed into an area of the body (the bladder or intestine, for example) to allow examination of that area. The endoscope usually has a fiber-optic camera, which allows a greatly magnified image to be shown on a television screen viewed by the operator. Many endoscopes also allow the operator to retrieve a biopsy of the area examined.

Fistula— An abnormal channel that creates an open passageway between two structures that do not normally connect.

Gastrointestinal tract— The entire length of the digestive system, running from the mouth to the stomach, through the small intestine, large intestine, rectum, and anus.

Immune system— The body system responsible for combating infection by viruses, bacteria, fungi, and other foreign invaders. In autoimmune disease, these cells and chemicals turn against the body itself.

Inflammation— The result of the body's attempts to fight off and wall off an area that is infected. Inflammation results in the classic signs of redness, heat, swelling, and loss of function.

Obstruction— A blockage.

Ulceration— A pitted area or break in the continuity of a surface such as skin or mucous membrane.

Prognosis

Crohn's disease is a chronic, lifelong illness. The severity of the disease may vary, and patients may experience periods of time when the disease is not active and they are symptom free. Still, the complications and risks of Crohn's disease tend to increase over time. More than 60% of all patients with Crohn's disease will require surgery, and about half of these will require more than one operation over time. Approximately 5-10% of all Crohn's patients die of their disease, primarily due to massive infection.

Health care team roles

Crohn's disease is often diagnosed by primary care practitioners or gastroenterologists. In many instances, patients require surgical intervention. Imaging studies to assist in diagnosis are performed by x-ray technologists, and laboratory technologists may be involved in obtaining blood and stool samples for analysis.

Nurses, dieticians, and nutritional counselors have important roles in teaching patients about dietary changes to manage symptoms. Nurses, social workers, and ostomy specialists may also be involved in educating patients pre- and postoperatively about ostomy care.

Prevention

Presently, there is no way to prevent the development of Crohn's disease.

Resources

BOOKS

Glickman, Robert. "Inflammatory Bowel Disease: Ulcerative Colitis and Crohn's Disease." In Harrison's Principles of Internal Medicine, edited by Anthony S. Fauci, et al. New York: McGraw-Hill, 1998.

Long, James W. The Essential Guide to Chronic Illness. New York: Harper Perennial, 1997.

Saibil, Fred. Crohn's Disease and Ulcerative Colitis. Buffalo, NY: Firefly Books, 1997.

ORGANIZATIONS

Crohn's & Colitis Foundation of America, Inc. 386 Park Avenue South, 17th Floor, New York, NY 10016-8804. (800) 932-2423.

Crohn's Disease

views updated May 18 2018

CROHN'S DISEASE

DEFINITION


Crohn's disease (pronounced krohnz) is a type of inflammatory bowel disease. It results in swelling of the intestinal tract. It may also restrict the function of the intestinal tract.

DESCRIPTION


The term inflammatory bowel diseases (IBD) refers to a large group of disorders that affect the gastrointestinal (digestive) system. The gastrointestinal (GI) system includes the stomach, small intestine, and large intestine. For reasons that are still not understood, portions of the GI system sometimes become inflamed. Researchers think that the body's immune system may sometimes cause this inflammation. It attacks the lining of the GI system the way it normally attacks invading foreign bodies.

Two of the most important of these disorders are Crohn's disease and ulcerative colitis (see ulcerative colitis entry). These disorders differ from each other in two primary ways:

  • The inflammation caused by Crohn's disease may occur in patches separated from each other on the GI lining. Ulcerative colitis produces one large area of inflammation.
  • The inflammation of Crohn's disease can penetrate deep into the wall of the intestine. Ulcerative colitis affects only the lining of the intestine.

Crohn's disease can affect people of all ages and both sexes. It occurs most commonly in individuals between the ages of fifteen and thirty-five. About 2 to 4 out of 10,000 people develop the condition. Crohn's disease occurs more commonly among whites, especially people of Jewish ancestry. Crohn's disease is a chronic (ongoing) disorder. Its symptoms may improve, but a person is never completely cured.

CAUSES


The cause of Crohn's disease is unknown. Some researchers believe that it may be triggered by an infection. But no infectious agent, such as a bacterium or virus, has ever been discovered. There is some evidence that the disease may be an autoimmune disorder (see autoimmune disorder entry). An autoimmune disorder is a condition in which the body's immune system becomes confused. It begins to attack body tissue just as it would attack invading organisms, such as bacteria or viruses. However, no proof for this theory has yet been obtained.

SYMPTOMS


The first symptoms of Crohn's disease include diarrhea, fever, abdominal pain, inability to eat, weight loss, and fatigue. The abdominal pain is somewhat like that experienced by an individual with appendicitis (see appendicitis entry). An ongoing symptom of Crohn's disease may be malnutrition. Inflammation caused by the disorder interferes with the absorption of nutrients in foods and a patient may slowly become more and more malnourished.

Crohn's Disease: Words to Know

Abscess:
A pocket of infection within tissue.
Arthritis:
Inflammation of a joint.
Barium enema:
A procedure in which a white liquid is injected into a patient's rectum in order to coat the lining of the colon so that X-ray photographs of the colon can be taken.
Colonoscope:
An instrument consisting of a long, flexible tube with a light attached to the end, used for examining the lining of the colon.
Fistula:
An abnormal tube-like passage in tissue.
Gastrointestinal system:
The digestive system consisting of the stomach and intestines.
Immune system:
A network of organs, tissues, cells, and chemicals designed to protect the body against foreign invaders such as bacteria and viruses.
Inflammation:
Redness, swelling, and loss of function caused by the body's attempt to fight off an infection.
Inflammatory bowel disease:
A large group of disorders that affect the gastrointestinal system.
Obstruction:
A blockage.

Crohn's disease also can lead to a number of complications. These complications include:

  • Obstructions. An obstruction is a blockage of the intestine. Partially digested food is not able to pass through the intestine. It may back up, causing constipation, vomiting, and intense pain.
  • Abscesses. An abscess is a pocket of infection within tissue. Abscesses in the intestine may cause fever and severe abdominal pain.
  • Fistulas. A fistula is an abnormal tube-like passage in tissue. Fistulas may allow fluids to drain out of the intestine into another part of the body. When they do so, bacteria that live in the intestine may cause infections in other areas of the body.
  • Gallstones and kidney stones
  • Kidney damage
  • Arthritis (see arthritis entry)
  • Inflammation of the vertebrae, the bones of the spine
  • Ulcers of the mouth and skin
  • Painful, red bumps on the skin
  • Inflammation of the eyes, liver, and gallbladder

DIAGNOSIS


An individual may be suspected to have Crohn's if he or she begins to experience the described symptoms. Blood tests may provide some additional information by showing the presence of infection or malnutrition. Stool samples may be needed to rule out other GI disorders, such as ulcerative colitis, that have symptoms similar to those of Crohn's disease.

The most reliable method for diagnosing Crohn's disease is with a colonoscopy (pronounced KO-lon-OSS-kuh-pee). A colonoscope (pronounced ko-LON-o-skope) consists of a long, flexible tube with a light attached to the end. The tube is inserted into the patient's rectum. It is then threaded upward into the colon. With the colonoscope, a doctor is able to examine the walls of the colon. The presence of inflammation suggests a diagnosis of Crohn's disease.

The colonoscope may also have a small, sharp knife attached at the end. With the knife, a doctor can remove a tiny sample of tissue, which can then be examined under a microscope. Certain distinctive characteristics of cells indicate the presence of Crohn's disease.

A barium enema is sometimes used to confirm a diagnosis of Crohn's disease. A barium enema consists of a white liquid that is injected into the patient's rectum. The liquid moves upward into the colon and coats the lining of the colon. X-ray photographs of the colon are then taken. The white lining produces a clear X-ray photograph that shows the presence of any abnormal structures in the GI tract.

CROHN'S NAMESAKE

Scientists have known about Crohn's disease for more than two hundred years. The first description of the condition was probably written by the Italian physician Giovanni Battista Morgagni (16821771). But the real pioneer of research on this disease was the American physician, Burrill B. Crohn (18841983). Crohn was born in New York City and earned his medical degree from Columbia University College of Physicians and Surgeons. He spent most of his professional career at Mount Sinai Hospital in New York. Crohn first described the condition that now bears his name in 1932.

How did Crohn first become interested in digestive problems? When asked this question, he gave an interesting answer. According to Crohn, his father had long suffered from very bad cases of indigestion, so he decided to become a doctor in order to learn what would bring his father relief. Crohn was obviously a very good son and a very good physician!

TREATMENT


Treatment for Crohn's disease focuses on four major objectives:

  • Reduction of inflammation of the intestine
  • Dealing with the patient's nutritional problems
  • Relieving the uncomfortable symptoms of abdominal pain and diarrhea
  • Treating possible complications, such as obstructions, abscesses, and fistulas

Inflammation is usually treated with a drug called sulfasalazine (pronounced SULL-fuh-SAL-uh-zeen). Sulfasalazine consists of two parts. One part is an antibiotic and the other part an anti-inflammatory agent. For patients who do not respond to sulfasalazine, steroids may be used. Steroids are very effective in reducing inflammation. However, they have some undesirable side effects.

Nutritional supplements are used to treat malnutrition. The supplements are chosen because they are easily absorbed through the intestinal wall. Patients may also need to learn which foods they cannot digest (such as milk or spicy foods) and avoid eating those foods. In severe cases, a patient may need to be fed intravenously. Intravenous feeding involves the insertion of a tube into a vein. Nutrients are then given to the patient through the tube.

A number of medications are available to reduce pain and cramping. High-fiber medications may also be helpful.

Complications such as obstructions, abscesses, and fistulas are sometimes treated with antibiotics. The antibiotics kill the bacteria that produce these complications. If antibiotics are unsuccessful, surgery may be necessary. The purpose of surgery is to remove an obstruction or abscess or to repair a fistula. In the most severe cases, a portion of the intestine may have to be removed.

PROGNOSIS


Crohn's disease is a chronic, lifelong illness. The severity of the condition differs for various patients. Some patients go through periods when they have no symptoms. Symptoms then flare up again at a later time.

The complications of Crohn's disease can lead to serious health problems. The risk for these complications increases over time. More than 60 percent of all patients with the disorder require surgery at one time or another. More than half require more than one operation. About 5 to 10 percent of all Crohn's patients die of the disorder. In most cases, death is caused by widespread infection.

FOR MORE INFORMATION


Books

Long, James W. The Essential Guide to Chronic Illness. New York: Harper Perennial, 1997.

Saibil, Fred. Crohn's Disease and Ulcerative Colitis. Buffalo, NY: Firefly Books, 1997.

Thompson, W. Grant. The Angry Gut: Coping With Colitis and Crohn's Disease. New York: Plenum Press, 1993.

Organizations

Crohn's & Colitis Foundation of America, Inc. 386 Park Avenue South, 17th Floor, New York, NY 100168804. (800) 9322423.

Crohn's disease

views updated May 23 2018

Crohn's disease (krohnz) n. a condition in which segments of the alimentary tract become inflamed, thickened, and ulcerated. It usually affects the terminal part of the ileum; its acute form (acute ileitis) sometimes mimics appendicitis. Chronic disease often causes partial obstruction of the intestine, leading to pain, diarrhoea, and malabsorption. Alternative names: regional enteritis, regional ileitis. [ B. B. Crohn (1884–1983), US physician]

About this article

Crohns Disease

All Sources -
Updated Aug 13 2018 About encyclopedia.com content Print Topic