Crohn's Disease

What is Crohn's disease?

Crohn's disease is a chronic inflammatory disease of the intestines. It primarily causes ulcerations (breaks in the lining) of the small and large intestines, but can affect the digestive system anywhere from the mouth to the anus. It is named after the physician who described the disease in 1932. It also is called granulomatous enteritis or colitis, regional enteritis, ileitis, or terminal ileitis.

Crohn's disease is related closely to another chronic inflammatory condition that involves only the colon called ulcerative colitis. Together, Crohn's disease and ulcerative colitis are frequently referred to as inflammatory bowel disease (IBD). Ulcerative colitis and Crohn's disease have no medical cure. Once the diseases begin, they tend to fluctuate between periods of inactivity (remission) and activity (relapse). They affect approximately 500,000 to two million people in the United States. Men and women are equally affected. IBD most commonly begins during adolescence and early adulthood, but it also can begin during childhood and later in life.

Crohn's disease tends to be more common in relatives of patients with Crohn's disease. It also is more common among relatives of patients with ulcerative colitis.

What causes Crohn's disease?

The cause of Crohn's disease is unknown. Some scientists suspect that infection by certain bacteria, such as strains of mycobacterium, may be the cause of Crohn's disease. To date, however, there has been no convincing evidence that the disease is caused by infection. Crohn's disease is not contagious. Although diet may affect the symptoms in patients with Crohn's disease, it is unlikely that diet is responsible for the disease.

Activation of the immune system in the intestines appears to be important in IBD. The immune system is composed of immune cells and the proteins that these immune cells produce. Normally, these cells and proteins defend the body against harmful bacteria, viruses, fungi, and other foreign invaders. Activation of the immune system causes inflammation within the tissues where the activation occurs. (Inflammation is an important mechanism of defense used by the immune system.)

Normally, the immune system is activated only when the body is exposed to harmful invaders. In patients with IBD, however, the immune system is abnormally and chronically activated in the absence of any known invader. The continued abnormal activation of the immune system results in chronic inflammation and ulceration. The susceptibility to abnormal activation of the immune system is genetically inherited. Thus, first degree relatives (brothers, sisters, children, and parents) of patients with IBD are more likely to develop these diseases. Recently a gene called NOD2 has been identified as being associated with Crohn's disease. This gene is important in determining how the body responds to some bacterial products. Individuals with mutations in this gene are more susceptible to developing Crohn's disease.

How does Crohn's disease affect the intestines?

In the early stages, Crohn's disease causes small, scattered, shallow, crater–like areas (erosions) on the inner surface of the bowel. These erosions are called aphthous ulcers. With time, the erosions become deeper and larger, ultimately becoming true ulcers (which are deeper than erosions) and causing scarring and stiffness of the bowel. As the disease progresses, the bowel becomes increasingly narrowed, and ultimately can become obstructed. Deep ulcers can puncture holes in the wall of the bowel, and bacteria from within the bowel can spread to infect adjacent organs and the surrounding abdominal cavity.

When Crohn's disease narrows the small intestine to the point of obstruction, the flow of the contents through the intestine ceases. Sometimes, the obstruction can be caused suddenly by poorly–digestible fruit or vegetables that plug the already–narrowed segment of the intestine. When the intestine is obstructed, digesting food, fluid and gas from the stomach and the small intestine cannot pass into the colon. The symptoms of small intestinal obstruction then appear, including severe abdominal cramps, nausea, vomiting, and abdominal distention. Obstruction of the small intestine is much more likely since the small intestine is much narrower than the colon to begin with.

Deep ulcers can puncture holes in the walls of the small intestine and the colon, and create a tunnel between the intestine and adjacent organs. If the ulcer tunnel reaches an adjacent empty space inside the abdominal cavity, a collection of infected pus (an abdominal abscess) is formed. Patients with abdominal abscesses can develop tender abdominal masses, high fevers, and abdominal pain.

When the ulcer tunnels into an adjacent organ, a channel (fistula) is formed. The formation of a fistula between the intestine and the bladder (enteric–vesicular fistula) can cause frequent urinary tract infections and the passage of gas and feces during urination. When a fistula develops between the intestine and the skin (enteric–cutaneous fistula), pus and mucous emerge from a small painful opening on the skin of the abdomen. The development of a fistula between the colon and the vagina (colonic–vaginal fistula) causes gas and feces to emerge through the vagina. The presence of a fistula from the intestines to the anus (anal fistula) leads to a discharge of mucous and pus from the fistula's opening around the anus.

How is Crohn's disease different from ulcerative colitis?

While ulcerative colitis causes inflammation only in the colon (colitis) and/or the rectum (proctitis), Crohn's disease may cause inflammation in the colon, rectum, small intestine (jejunum and ileum), and, occasionally, even the stomach, mouth, and esophagus.

The patterns of inflammation in Crohn's disease are different from ulcerative colitis. Except in the most severe cases, the inflammation of ulcerative colitis tends to involve the superficial layers of the inner lining of the bowel. The inflammation also tends to be diffuse and uniform. (All of the lining in the affected segment of the intestine is inflamed.) Unlike ulcerative colitis, the inflammation of Crohn's disease is concentrated in some areas more than others and involves layers of the bowel that are deeper than the superficial inner layers. Therefore, the affected segment(s) of bowel in Crohn's disease often is studded with deeper ulcers with normal lining between these ulcers.

What are the symptoms of Crohn's disease?

Common symptoms of Crohn's disease include abdominal pain, diarrhea, and weight loss. Less common symptoms include poor appetite, fever, night sweats, rectal pain, and rectal bleeding. The symptoms of Crohn's disease are dependent on the location, the extent, and the severity of the inflammation. The different subtypes of Crohn's disease and their symptoms are:

1. Crohn's colitis is inflammation that is confined to the colon. Abdominal pain and bloody diarrhea are the common symptoms. Anal fistulae and peri–rectal abscesses also can occur.

2. Crohn's enteritis refers to inflammation confined to the small intestine (the first part, called the jejunum or the second part, called the ileum). Involvement of the ileum alone is referred to as Crohn's ileitis. Abdominal pain and diarrhea are the common symptoms. Obstruction of the small intestine also can occur.

3. Crohn's terminal ileitis is inflammation that affects only the very end of the small intestine (terminal ileum), the part of the small intestine closest to the colon. Abdominal pain and diarrhea are the common symptoms. Small intestinal obstruction also can occur.

4. Crohn's entero–colitis and ileo–colitis are terms to describe inflammation that involve both the small intestine and the colon. Bloody diarrhea and abdominal pain are the common symptoms. Small intestinal obstruction also can occur.

Crohn's terminal ileitis and ileo–colitis are the most common types of Crohn's disease. (Ulcerative colitis frequently involves only the rectum or rectum and sigmoid colon at the distal end of the colon. These are called ulcerative proctitis and procto–sigmoiditis, respectively.)

Up to one third of patients with Crohn's disease may have one or more of the following conditions involving the anal area:

1. Swelling of the tissue of the anal sphincter, the muscle at the end of the colon that controls defecation.

2. Development of ulcers and fissures (long ulcers) within the anal sphincter. These ulcers and fissures can cause bleeding and pain with defecation.

3. Development of anal fistulae (abnormal tunnels) between the anus or rectum and the skin surrounding the anus). Mucous and pus may drain from the openings of the fistulae on the skin.

4. Development of peri–rectal abscesses (collections of pus in the anal and rectal area). Peri–rectal abscesses can cause fever, pain and tenderness around the anus.

What are the complications of Crohn's disease?

Complications of Crohn's disease may be related or unrelated to the inflammation within the intestine (such as intestinal or extra–intestinal). Intestinal complications of Crohn's disease include obstruction and perforation of the small intestine, abscesses (collections of pus), fistulae, and intestinal bleeding. Massive distention or dilatation of the colon (megacolon), and rupture (perforation) of the intestine are potentially life–threatening complications. Both generally require surgery, but, fortunately, these two complications are rare. Recent data suggest that there is an increased risk of cancer of the small intestine and colon in patients with long–standing Crohn's disease.

Extra–intestinal complications involve the skin, joints, spine, eyes, liver, and bile ducts. Skin involvement includes painful red raised spots on the legs (erythema nodosum) and an ulcerating skin condition generally found around the ankles called pyoderma gangrenosum. Painful eye conditions (uveitis, episcleritis) can cause visual difficulties. Arthritis can cause pain, swelling, and stiffness of the joints of the extremities. Inflammation of the low back (sacroiliac joint arthritis) and of the spine (ankylosing spondylitis) can cause pain and stiffness of the spine. Inflammation of the liver (hepatitis) or bile ducts (primary sclerosing cholangitis) also can occur. Sclerosing cholangitis causes narrowing and obstruction of the ducts draining the liver and can lead to yellow skin (jaundice), recurrent bacterial infections, and liver cirrhosis with liver failure. Sclerosing cholangitis with liver failure is one of the reasons for performing liver transplantation. Sclerosing cholangitis frequently is complicated by the development of cancer of the bile ducts.

How is Crohn's disease diagnosed?

The diagnosis of Crohn's disease is suspected in patients with fever, abdominal pain and tenderness, diarrhea with or without bleeding, and anal diseases. Laboratory blood tests may show elevated white cell counts and sedimentation rates, both of which suggest infection or inflammation. Other blood tests may show low red blood cell counts (anemia), low blood proteins, and low body minerals, reflecting loss of these elements due to chronic diarrhea.

Barium x–ray studies can be used to define the distribution, nature, and severity of the disease. Barium is a chalky material that is visible by x–ray and appears white on x–ray films. When barium is ingested orally (upper GI series) it fills the intestine and pictures (x–rays) can be taken of the stomach and the small intestines. When barium is administered through the rectum (barium enema), pictures of the colon and the terminal ileum can be obtained. Barium x–rays can show ulcerations, narrowing, and, sometimes, fistulae of the bowel.

Direct visualization of the rectum and the large intestine can be accomplished with flexible viewing tubes (colonoscopes). Colonoscopy is more accurate than barium x–rays in detecting small ulcers or small areas of inflammation of the colon and terminal ileum. Colonoscopy also allows for small tissue samples (biopsies) to be taken and sent for examination under the microscope to confirm the diagnosis of Crohn's disease. Colonoscopy also is more accurate than barium x–rays in assessing the degree (activity) of inflammation.

Computerized axial tomography (CAT or CT) scanning is a computerized x–ray technique that allows imaging of the entire abdomen and pelvis. It can be especially helpful in detecting abscesses.

Most recently, video capsule endoscopy has been added to the list of diagnostic tests for diagnosing Crohn's disease. For video capsule endoscopy, a capsule containing a miniature video camera is swallowed. As the capsule travels through the small intestine, it sends video images of the lining of the small intestine to a receiver carried on a belt at the waist. The images are downloaded and then reviewed on a computer. The value of video capsule endoscopy is that it can identify the early, mild abnormalities of Crohn's disease. Video capsule endoscopy may be particularly useful when there is a strong suspicion of Crohn's disease but the barium x–rays are normal. (Barium x–rays are not as good at identifying early, mild Crohn's disease.)

Video capsule endoscopy should not be performed in patients who have obstruction of the small intestine. The capsule may get stuck behind the obstruction and make the obstruction worse. Doctors usually also are reluctant to perform video–capsule endoscopy for the same reason in patients who they suspect of having small intestinal strictures (narrowed segments of small intestine that can result from prior surgery, prior radiation, or chronic ulceration, for example, from Crohn's disease). There is also a theoretical concern for electrical interference between the capsule and implanted cardiac pacemakers and defibrillators; however, so far in a small number of patients with pacemakers or defibrillators who have undergone video capsule endoscopy there have been no problems.

How is Crohn's disease treated?

The symptoms and severity of Crohn's disease vary among patients. Patients with mild or no symptoms may not need treatment. Patients whose disease is in remission (where symptoms are absent) also may not need treatment.

There is no medication that can cure Crohn's disease. Patients with Crohn's disease typically will experience periods of relapse (worsening of inflammation) followed by periods of remission (reduced inflammation) lasting months to years. During relapses, symptoms of abdominal pain, diarrhea, and rectal bleeding worsen. During remissions, these symptoms improve. Remissions usually occur because of treatment with medications or surgery, but occasionally they occur spontaneously without any treatment.

Since there is no cure for Crohn's disease, the goals of treatment are to 1) induce remissions, 2) maintain remissions, 3) minimize side effects of treatment, and 4) improve the quality of life. Treatment of Crohn's disease and ulcerative colitis with medications is similar though not always identical.

Medications for treating Crohn's disease include 1) antiinflammatory agents such as 5–ASA compounds, corticosteroids, topical antibiotics, 2) immuno–modulators, 3) other medications.

Antiinflammatory medications

Antiinflammatory medications that decrease intestinal inflammation are analogous to arthritis medications that decrease joint inflammation. Different types of antiinflammatory medications used in the treatment of Crohn's disease are:

• 5–ASA compounds such as sulfasalazine (Azulfidine) and mesalamine (Pentasa, Asacol, Dipentum, Colazal, Rowasa enema, Canasa suppository) that act via direct contact (topically) with the inflamed tissue in order to be effective.
  
  
• Corticosteroids that act systemically (without the need for direct contact with the inflamed tissue) to decrease inflammation throughout the body. Systemic corticosteroids have important and predictable side effects if used long–term.
  
  
• A new class of topical corticosteroid (for example, budesonide) that acts via direct contact (topically) with the inflamed tissue. This class of corticosteroids has fewer side effects than systemic corticosteroids which are absorbed into the body.
  
  
• Antibiotics such as metronidazole (Flagyl) and ciprofloxacin (Cipro) that decrease inflammation by an unknown mechanism

5–ASA (mesalamine) oral medications

5–aminosalicylic acid (5–ASA), also called mesalamine, is similar chemically to aspirin. Aspirin has been used for many years for treating arthritis, bursitis, and tendonitis (conditions of tissue inflammation). Aspirin, however, is not effective in treating Crohn's disease and ulcerative colitis, and even may worsen the inflammation. On the other hand, 5–ASA can be effective in treating Crohn's disease and ulcerative colitis if the drug can be delivered topically onto the inflamed intestinal lining. For example, mesalamine (Rowasa) is an enema containing 5–ASA that is effective in treating inflammation in the rectum. However, the enema solution cannot reach high enough to treat inflammation in the upper colon and the small intestine. Therefore, for most patients with Crohn's disease involving both the ileum (distal small intestine) and colon, 5–ASA must be taken orally.

If pure 5–ASA is taken orally, however, most of the 5–ASA would be absorbed in the stomach and the upper small intestine, and very little 5–ASA would reach the ileum and colon. To be effective as an oral agent in treating Crohn's disease, 5–ASA has to be modified chemically to escape absorption by the stomach and the upper intestines.

Sulfasalazine (Azulfidine)

Sulfasalazine (Azulfidine) was the first modified 5–ASA compound used in the treatment of Crohn's colitis and ulcerative colitis. It has been used successfully for many years to induce remissions among patients with mild to moderate ulcerative colitis. Sulfasalazine also has been used for prolonged periods for maintaining remissions.

Sulfasalazine consists of a 5–ASA molecule linked chemically to a sulfapyridine molecule. (Sulfapyridine is a sulfa antibiotic.) Connecting the two molecules together prevents absorption by the stomach and the upper intestines. When sulfasalazine reaches the ileum and the colon, the bacteria that normally are present break the link between the two molecules. After breaking away from 5–ASA, sulfapyridine is absorbed into the body and later eliminated in the urine. Most of the active 5–ASA, however, is available within the terminal ileum and colon to treat the colitis.

Most of the side effects of sulfasalazine are due to the sulfapyridine molecule. These side effects include nausea, heartburn, headache, anemia, skin rashes, and, in rare instances, hepatitis and kidney inflammation. In men, sulfasalazine can reduce the sperm count. The reduction in sperm count is reversible, and the count usually becomes normal after the sulfasalazine is discontinued or changed to a different 5– ASA compound.

Because the newer 5–ASA compounds [for example, mesalamine (Asacol and Pentasa)] do not have the sulfapyridine component and have fewer side effects than sulfasalazine, they are being used more frequently in treating Crohn's disease and ulcerative colitis.

Asacol

Asacol is a tablet consisting of the 5–ASA compound surrounded by an acrylic resin coating. Asacol is sulfa–free. The resin coating prevents the 5–ASA from being absorbed as it passes through the stomach and the small intestine. When the tablet reaches the terminal ileum and the colon, the resin coating dissolves, and the active 5–ASA drug is released.

Asacol is effective in inducing remissions in patients with mild to moderate ulcerative colitis. It also is effective when used in the longer term to maintain remissions. Some studies have shown that Asacol also is effective in treating Crohn's ileitis and ileo–colitis, as well as in maintaining remission in patients with Crohn's disease.

The recommended dose of Asacol for inducing remissions is two 400 mg tablets three times daily (a total of 2.4 grams a day). At least two tablets of Asacol twice daily (1.6 grams a day) is recommended for maintaining remission. Occasionally, the maintenance dose is higher.

As with Azulfidine, the benefits of Asacol are dose–related. If patients do not respond to 2.4 grams a day of Asacol, the dose frequently is increased to 3.6 – 4.8 grams a day to induce remission. If patients fail to respond to the higher doses of Asacol, then other alternatives such as corticosteroids are considered.

Pentasa

Pentasa is a capsule consisting of small spheres containing 5–ASA. Pentasa is sulfa–free. As the capsule travels down the intestines, the 5–ASA inside the spheres is released slowly into the intestine. Unlike Asacol, the active drug 5–ASA in Pentasa is released into the small intestine as well as the colon. Therefore, Pentasa can be effective in treating inflammation in the small intestine and is currently the most commonly used 5–ASA compound for treating mild to moderate Crohn's disease in the small intestine.

Patients with Crohn's disease occasionally undergo surgery to relieve small intestinal obstruction, drain abscesses, or remove fistulae. Usually, the diseased portions of the intestines are removed during surgery. After successful surgery, patients can be free of disease and symptoms (in remission) for a while. In many patients, however, Crohn's disease eventually returns. Pentasa helps maintain remissions and reduces the chances of the recurrence of Crohn's disease after surgery.

In the treatment of Crohn's ileitis or ileocolitis, the dose of Pentasa usually is four 250 mg capsules four times daily (a total of 4 grams a day). For maintenance of remission in patients after surgery, the dose of Pentasa is between 3–4 grams daily.

Olsalazine (Dipentum)

Olsalazine (Dipentum) is a capsule in which two molecules of 5–ASA are joined together by a chemical bond. In this form, the 5–ASA cannot be absorbed from the stomach and intestine. Intestinal bacteria are able to break apart the two molecules releasing the active individual 5–ASA molecules into the intestine. Since intestinal bacteria are more abundant in the ileum and colon, most of the active 5–ASA is released in these areas. Therefore, olsalazine is most effective for disease that is limited to the ileum or colon. Although clinical studies have shown that olsalazine is effective for maintenance of remission in ulcerative colitis, up to 11% of patients experience diarrhea when taking olsalazine. Because of this, olsalazine is not often used. The recommended dose of olsalazine is 500 mg twice a day.

Balsalazide (Colazal)

Balsalazide (Colazal) is a capsule in which the 5–ASA is linked by a chemical bond to another molecule that is inert (without effect on the intestine) and prevents the 5–ASA from being absorbed. This drug is able to travel through the intestine unchanged until it reaches the end of the small bowel (terminal ileum) and colon. There, intestinal bacteria break apart the 5–ASA and the inert molecule releasing the 5–ASA. Because intestinal bacteria are most abundant in the terminal ileum and colon, balsalazide is used to treat inflammatory bowel disease predominantly localized to the colon.

Side effects of oral 5–ASA compounds

The 5–ASA compounds have fewer side effects than Azulfidine and also do not reduce sperm counts. They are safe medications for long–term use and are well–tolerated.

Patients allergic to aspirin should avoid 5–ASA compounds because they are similar chemically to aspirin.

Rare kidney and lung inflammation has been reported with the use of 5–ASA compounds. Therefore, 5–ASA should be used with caution in patients with kidney disease. It also is recommended that blood tests of kidney function be done before starting and periodically during treatment.

Rare instances of worsening of diarrhea, cramps, and abdominal pain, at times accompanied by fever, rash, and malaise, may occur. This reaction is believed to represent an allergy to the 5–ASA compound.

5–ASA rectal medications (Rowasa Canasa)

Rowasa is 5–ASA in enema form. 5–ASA by enema is most useful for treating ulcerative colitis involving only the distal colon since the enema easily can reach the inflamed tissues of the distal colon. Rowasa also is used in treating Crohn's disease in which there is inflammation in and near the rectum. Each Rowasa enema contains 4 grams of 5–ASA. The enema usually is administered at bedtime, and patients are encouraged to retain the enema through the night. The enema contains sulfite and should not be used by patients with sulfite allergy. Otherwise, Rowasa enemas are safe and well–tolerated.

Canasa is 5–ASA in suppository form. It is used for treating ulcerative proctitis. Each suppository contains 500 mg of 5–ASA and usually is administered twice daily.

Both enemas and suppositories have been shown to be effective in maintaining remission in patients with ulcerative colitis limited to the distal colon and rectum.

Corticosteroids

Corticosteroids (for example, prednisone, prednisolone, hydrocortisone, etc.) have been used for many years to treat patients with moderate to severe Crohn's disease and ulcerative colitis and to treat patients who fail to respond to 5–ASA. Unlike 5–ASA, corticosteroids do not require direct contact with the inflamed intestinal tissues to be effective.

Oral corticosteroids are potent antiinflammatory medications. After absorption, corticosteroids exert prompt antiinflammatory actions throughout the body, including the intestines. Consequently, they are used in treating Crohn's disease anywhere in the small intestine, as well as ulcerative and Crohn's colitis. In critically ill patients, intravenous corticosteroids (such as hydrocortisone) can be given in the hospital. For patients with proctitis, hydrocortisone enemas (Cortenema) can be used to deliver the corticosteroid directly to the inflamed tissue. By using the corticosteroid topically, less of it is absorbed into the body and the frequency and severity of side effects are lessened (but not eliminated) as compared with systemic corticosteroids.

Corticosteroids are faster–acting than 5–ASA, and patients frequently experience improvement in their symptoms within days of beginning them. Corticosteroids, however, do not appear to be useful in maintaining remission in Crohn's disease and ulcerative colitis or in preventing the return of Crohn's disease after surgery.

Side effects of corticosteroids

The frequency and severity of side effects of corticosteroids depend on the dose and duration of their use. Short courses of corticosteroids, for example, usually are well–tolerated with few and mild side effects. Long–term use of high doses of corticosteroids usually produces predictable and potentially serious side effects. Common side effects include:

• rounding of the face (moon face),
  
  
• acne,
  
  
• increased body hair,
  
  
• diabetes,
  
  
• weight gain,
  
  
• high blood pressure,
  
  
• cataracts,
  
  
• glaucoma,
  
  
• increased susceptibility to infections,
  
  
• muscle weakness,
  
  
• depression,
  
  
• insomnia,
  
  
• mood swings,
  
  
• personality changes,
  
  
• irritability, and
  
  
• thinning of the bones (osteoporosis) with fractures of the spine.
  
  

Children receiving corticosteroids experience stunted growth.

The most serious complication from long term corticosteroid use is aseptic necrosis of the hip joints. Aseptic necrosis is a condition in which there is death and degeneration of the hip bone. It is a painful condition that can ultimately lead to the need for surgical replacement of the hip. Aseptic necrosis also has been reported in the knee joints. It is not known how corticosteroids cause aseptic necrosis. The estimated incidence of aseptic necrosis among corticosteroid users is 3%–4%. Patients on corticosteroids who develop pain in the hips or knees should report the pain to their doctors promptly. Early diagnosis of aseptic necrosis with cessation of corticosteroids might decrease the severity of the aseptic necrosis and the need for hip replacement surgery.

Prolonged use of corticosteroids can depress the ability of the body's adrenal glands to produce cortisol (a natural corticosteroid necessary for proper functioning of the body). Therefore, abruptly discontinuing corticosteroids can cause symptoms due to a lack of natural cortisol (a condition called adrenal insufficiency). Symptoms of adrenal insufficiency include nausea, vomiting, and even shock. Withdrawing corticosteroids too quickly also can produce symptoms of joint pain, fever, and malaise. Therefore, when corticosteroids are discontinued, the dose usually is tapered gradually rather than stopped abruptly.

Even after corticosteroids are discontinued, the adrenal glands' ability to produce cortisol can remain depressed from months up to two years. The depressed adrenal glands may not be able to produce increased amounts of cortisol to help the body handle the stress of accidents, surgery, and infections. Therefore, patients need additional corticosteroids during stressful situations to avoid developing adrenal insufficiency. Because corticosteroids are not useful in maintaining remission in ulcerative colitis and Crohn's disease, and because they have predictable and potentially serious side effects, they should be used for the shortest possible length of time.

Proper use of corticosteroids

Once the decision is made to use systemic corticosteroids, treatment usually is initiated with prednisone, 40–60 mg daily. The majority of patients with Crohn's disease respond with an improvement in symptoms within a few weeks. Once symptoms have improved, prednisone is reduced by 5–10 mg per week until a dose of 20 mg per day is reached. The dose then is reduced at a slower rate until the corticosteroid is discontinued. Gradually reducing corticosteroids not only minimizes the symptoms of adrenal insufficiency, it also reduces the chances of an abrupt recurrence of inflammation.

Many doctors use 5–ASA compounds and corticosteroids together. In patients who achieve remission with corticosteroids, 5–ASA compounds often are continued alone to maintain remission.

In patients whose symptoms return corticosteroids are slowly being reduced, the dose of corticosteroids is increased slightly to control the symptoms. Once the symptoms are under control, the reduction of corticosteroids can resume at a slower pace. Unfortunately, many patients who require corticosteroids to induce remissions become corticosteroid dependent. These patients consistently develop symptoms whenever the corticosteroid dose falls below a certain level. In such patients who are corticosteroid dependent as well as in patients who are unresponsive to corticosteroids and other antiinflammatory medications, immuno–modulator medications or surgery must be considered. The management of patients who are corticosteroid dependent or patients with severe disease that responds poorly to medications is complex. Doctors who are experienced in treating ulcerative colitis and Crohn's disease and in using immuno–modulators should evaluate these patients.

Prevention of osteoporosis

Long–term use of corticosteroids can cause osteoporosis. Calcium is very important in the formation and maintenance of healthy bones. Corticosteroids decrease the absorption of calcium from the intestine and increase the loss of calcium from the kidneys. Increasing dietary calcium intake is important but alone cannot halt corticosteroid–induced osteoporosis. To prevent or minimize osteoporosis, management of patients on long–term corticosteroids should include:

• Adequate intake of calcium (1000 mg daily in premenopausal women, 1,500 mg daily in postmenopausal women) and vitamin D (800 units daily).
  
  
• Periodic review with the doctor of the need for continued corticosteroid treatment and use of the lowest effective dose if continued treatment is necessary.
  
  
• For patients taking corticosteroids for more than three months, a bone density study may be helpful in determining the extent of bone loss and the need for more aggressive treatment.
  
  
• Regular weight–bearing exercise and stopping smoking (cigarettes).
  
  
• Discussion with the doctor regarding the use of alendronate (Fosamax), risedronate (Actonel), or etidronate (Didronel) to prevent or treat corticosteroid–induced osteoporosis.

Budesonide (Entocort EC)

Budesonide (Entocort EC) is a new type of corticosteroid for treating Crohn's disease. Like other corticosteroids, budesonide is a potent antiinflammatory medication. Unlike other corticosteroids, however, budesonide acts only via direct contact with the inflamed tissues (topically) and not systemically. As soon as budesonide is absorbed into the body, the liver converts it into inactive chemicals. Therefore, for effective treatment of Crohn's disease, budesonide, like topical 5–ASA, must be brought into direct contact with the inflamed intestinal tissue.

Budesonide capsules contain granules that allow a slow release of the drug into the ileum and the colon. In a double–blind multicenter study (published in 1998), 182 patients with Crohn's ileitis and/or Crohn's disease of the right colon were treated with either budesonide (9 mg daily) or Pentasa (2 grams twice daily). Budesonide was more effective than Pentasa in inducing remissions while the side effects were similar to Pentasa. In another study comparing the effectiveness of budesonide with corticosteroids, budesonide was not better than corticosteroids in treating Crohn's disease but had fewer side effects.

Because budesonide is broken down by the liver into inactive chemicals, it has fewer side effects than systemic corticosteroids. It also suppresses the adrenal glands less than systemic corticosteroids. Budesonide will be available as an enema for the treatment of proctitis.

Budesonide has not been shown to be effective in maintaining remission in patients with Crohn's disease. If used long–term, budesonide also may cause some of the same side effects as corticosteroids. Because of this, the use of budesonide should be limited to short–term treatment for inducing remission. Most budesonide is released in the terminal ileum, it will have its best results in Crohn's disease limited to the terminal ileum.

It is not known whether budesonide is effective in treating patients with ulcerative colitis, and it is currently not recommended for the treatment of ulcerative colitis.

Antibiotics for Crohn's disease

Antibiotics such as metronidazole (Flagyl) and ciprofloxacin (Cipro) have been used for treating Crohn's colitis. Flagyl also has been useful in treating anal fistulae in patients with Crohn's disease. The mechanism of action of these antibiotics in Crohn's disease is not well understood.

Metronidazole (Flagyl)

Metronidazole (Flagyl) is an antibiotic that is used for treating several infections caused by parasites (for example, giardia) and bacteria (for example, infections caused by anaerobic bacteria, and vaginal infections). It is effective in treating Crohn's colitis and is particularly useful in treating patients with anal fistulae. Chronic use of metronidazole in doses higher than 1 gram daily can be associated with permanent nerve damage (peripheral neuropathy). The early symptoms of peripheral neuropathy are numbness and tingling in the fingertips, toes, and other parts of the extremities. Metronidazole should be stopped promptly if these symptoms appear. Metronidazole and alcohol together can cause severe nausea, vomiting, cramps, flushing, and headache. Patients taking metronidazole should avoid alcohol. Other side effects of metronidazole include nausea, headaches, loss of appetite, a metallic taste, and, rarely, a rash.

Ciprofloxacin (Cipro)

Ciprofloxacin (Cipro) is another antibiotic used in the treatment of Crohn's disease. It can be used in combination with metronidazole.

Summary of antiinflammatory medications

• Azulfidine, Asacol, Pentasa, Dipentum, Colazal and Rowasa all contain 5–ASA which is the active topical antiinflammatory ingredient. Azulfidine was the first 5–ASA medication used in treating ulcerative colitis and Crohn's disease, but the newer 5–ASA medications have fewer side effects.
  
  
• Pentasa and Asacol have been found to be effective in treating patients with Crohn's ileitis and ileo–colitis. Rowasa enemas and Canasa suppositories are safe and effective for treating patients with proctitis. For mild to moderate Crohn's ileitis or ileo–colitis, doctors usually start with Pentasa or Asacol. If Pentasa or Asacol is ineffective, doctors may try antibiotics such as Cipro or Flagyl for prolonged periods (often months).
  
  
• In patients with moderate to severe disease and in patients who fail to respond to 5–ASA compounds and/or antibiotics, systemic corticosteroids can be used. Systemic corticosteroids are potent and fast–acting antiinflammatory agents for treating Crohn's enteritis and colitis as well as ulcerative colitis.
  
  
• Systemic corticosteroids are not effective in maintaining remission in patients with Crohn's disease. Serious side effects can result from prolonged corticosteroid treatment.
  
  
• To minimize side effects, corticosteroids should be gradually tapered as soon as a remission is achieved. In patients who become corticosteroid dependent or are unresponsive to corticosteroid treatment, surgery or immuno–modulator treatment are considered.
  
  
• A new class of topical corticosteroids (budesonide) may have fewer side effects than systemic corticosteroids.

Immuno–modulator medications

Immuno–modulators are medications that affect the body's immune system. The immune system is composed of immune cells and the proteins that they produce. These cells and proteins serve to protect the body against harmful bacteria, viruses, fungi, and other foreign invaders. Activation of the immune system causes inflammation within the tissues where the activation occurs. (Inflammation is, in fact, an important mechanism used by the immune system to defend the body.) Normally, the immune system is activated only when the body is exposed to foreign invaders. In patients with Crohn's disease and ulcerative colitis, however, the immune system is abnormally and chronically activated in the absence of any known invader.

Immuno–modulators decrease tissue inflammation by reducing the population of immune cells and/or by interfering with their production of proteins. Decreasing the activity of the immune system with immuno–modulators increases the risk of infections; however, the benefits of controlling moderate to severe Crohn's disease usually outweigh the risks of infection due to weakened immunity. Examples of immuno–modulators are 6–mercaptopurine (6–MP), azathioprine (Imuran), methotrexate (Rheumatrex, Trexall), infliximab (Remicade), adalimumab (Humira).

Azathioprine (Imuran) and 6–mercaptopurine (6–MP, Purinethol)

Azathioprine (Imuran) and 6–mercaptopurine (6–MP, Purinethol) are medications that weaken the body's immune system by reducing the population of a class of immune cells called lymphocytes. Azathioprine and 6–MP are related chemically. (Actually, azathioprine is converted into 6–MP within the body.) In high doses, these two drugs have been useful in preventing rejection of transplanted organs and in treating leukemia. In low doses, they have been used for many years to treat patients with moderate to severe Crohn's disease and ulcerative colitis.

Azathioprine and 6–MP are increasingly recognized by doctors as valuable drugs in treating Crohn's disease and ulcerative colitis. Some 70% of patients with moderate to severe disease will benefit from these drugs. Azathioprine and 6–MP are used primarily in the following situations:

1. Severe Crohn's disease and ulcerative colitis not responding to corticosteroids.

2. The presence of undesirable corticosteroid–related side effects.

3. Corticosteroid dependency, a condition in which patients are unable to discontinue corticosteroids without developing relapses of their disease.

4. Maintenance of remission.

When azathioprine and 6–MP are added to corticosteroids in the treatment of Crohn's disease not responding to corticosteroids alone, there may be an improved response. Also, smaller doses and shorter courses of corticosteroids may be able to be used. Some patients can discontinue corticosteroids altogether without experiencing relapses of their disease. This corticosteroid–lowering effect has earned azathioprine and 6–MP their reputation as "steroid–sparing" medications.

In Crohn's disease patients with severe disease who suffer frequent relapses, 5–ASA may not be sufficient, and the more potent azathioprine and 6–MP will be necessary to maintain remissions. In the lower doses used to treat Crohn's disease, the long–term side effects of azathioprine or 6– MP are less serious than those of long–term corticosteroids or repeated courses of corticosteroids.

Patients with Crohn's disease may undergo surgery to remove a segment of the intestine that is obstructed or contains a fistula. After surgical removal of the diseased segments, the patients often will be free of disease and symptoms for a while, but many eventually will have their disease recur. During these recurrences, previously healthy intestine can become inflamed. Long–term 5–ASA (such as Pentasa) and 6–MP both are effective in reducing the chances of recurrence after surgery.

Anal fistulae can develop in some patients with Crohn's disease. Anal fistulae are abnormal tracts (tunnels) that form between the small intestine or colon and the skin around the anus. Drainage of fluid and mucous from the opening of the fistula is a troublesome problem. These fistulae are difficult to treat and do not heal readily. Metronidazole (Flagyl) has been used with some success in promoting healing of these fistulae. In difficult cases, azathioprine and 6–MP may be successful in promoting healing.

Side effects of azathioprine and 6–MP

Side effects of azathioprine and 6–MP include increased vulnerability to infections, inflammation of the liver (hepatitis) and the pancreas (pancreatitis), and bone marrow toxicity (interference with the formation of cells that circulate in the blood).

The goal of treatment with azathioprine and 6–MP is to lower the body's production of certain types of white blood cells (lymphocytes) in order to decrease the inflammation in the intestines; however, lowering the number of lymphocytes may increase vulnerability to infections. For example, in a group of patients with severe Crohn's disease unresponsive to standard doses of azathioprine, raising the dose of azathioprine helped to control the disease, but two patients developed cytomegalovirus (CMV) infection. (CMV typically infects individuals with weakened immune systems such as patients with AIDS and cancer patients receiving chemotherapy).

Azathioprine and 6–MP can induce inflammation of the liver (hepatitis) and pancreas (pancreatitis). Pancreatitis typically causes severe abdominal pain and sometimes vomiting. Pancreatitis due to azathioprine or 6–MP occurs in 3%–5% of patients, usually during the first several weeks of treatment. Patients who develop pancreatitis should not receive either of these two medications again.

Azathioprine and 6–MP also suppress the bone marrow. The bone marrow is where the red blood cells, white blood cells, and platelets are made. Actually, a slight reduction in the white cell count during treatment is desirable since it suggests that the dose of azathioprine or 6–MP is high enough to have an effect; however, excessively low red or white blood cell counts indicates bone marrow toxicity. Therefore, patients on azathioprine or 6–MP should have periodic blood counts (usually every two weeks initially and then every three months during maintenance) to monitor the effect of the drugs on the bone marrow.

Patients on long–term, high dose azathioprine to prevent rejection of the kidney after kidney transplantation have an increased risk of developing lymphoma, a malignant disease of lymph cells. There is no evidence at present that long term use of azathioprine or 6–MP, in the lower doses used in Crohn's disease, increases the risk of lymphoma, leukemia or other malignancies.

The use of azathioprine and 6–MP in pregnant women must be carefully considered. There are reports suggesting that the use of azathioprine or 6–MP in pregnancy is safer than once thought. The risk of continuing azathioprine or 6–MP during conception and pregnancy must be weighed against the risk of worsening disease if they are stopped. On the other hand, worsening disease has been shown clearly to be a significant risk to the fetus.

Other issues with azathioprine and 6–MP

One problem with 6–MP and azathioprine is their slow onset of action. Typically, full benefit of these drugs is not realized for three months or longer. During this time, corticosteroids frequently have to be maintained at high levels to control inflammation.

The reason for this slow onset of action is partly due to the way doctors prescribe these drugs. For example, 6–MP is typically started at a dose of 50 mg daily. The blood count is then checked two weeks later. If the lymphocytes are not reduced, the dose of 6–MP is increased. This cautious, stepwise approach helps reduce bone marrow and liver toxicity but also delays benefit from the drug.

Studies have shown that giving higher doses of 6–MP early can hasten the benefit of 6–MP without increasing the toxicity in most patients, but some patients do develop severe bone marrow toxicity. Scientists now believe that an individual's vulnerability to 6–MP toxicity is genetically inherited. Blood tests can be performed to identify those individuals with increased vulnerability to 6–MP toxicity. Blood tests also can be performed to measure the levels of certain by–products of 6–MP. The levels of these by–products in the blood help doctors more quickly determine whether the dose of 6–MP is right for the patient.

TPMT genetics and safety of azathioprine and 6–MP

Azathioprine is converted into 6–MP in the body and 6–MP then is partially converted in the body into inactive and non–toxic chemicals by an enzyme called thiopurine methyltransferase (TPMT). These chemicals then are eliminated from the body. The activity of TPMT enzyme (the ability of the enzyme to convert 6–MP into inactive and non–toxic chemicals) is genetically determined, and approximately 10% of the population in the Untied States has a reduced or absent TPMT activity. In this 10% of patients, 6–MP accumulates and is converted into chemicals that are toxic to the bone marrow where blood cells are produced. Thus, when given normal doses of azathioprine or 6–MP, these patients with reduced or absent TPMT activities can develop seriously low white blood cell counts for prolonged periods of time, exposing them to serious life–threatening infections.

Doctors now can perform genetic testing for TPMT before starting azathioprine or 6–MP. Patients found to have genes associated with reduced or absent TPMT activity are treated with alternative medications or are prescribed substantially lower than normal doses of 6–MP or Azathioprine.

A word of caution is in order, however. Having normal TPMT genes is no guarantee against azathioprine or 6–MP toxicity. Rarely, a patient with normal TPMT genes can develop severe toxicity in the bone marrow and a low white blood cell count even with normal doses of 6–MP or azathioprine. Therefore, all patients taking 6–MP or azathioprine (regardless of TPMT genetics) have to be closely monitored by a doctor who will order periodic blood counts for as long as the medication is taken.

Another cautionary note; allopurinol (Zyloprim), used in treating high blood uric acids levels, can induce bone marrow toxicity when used together with azathioprine or 6–MP. Zyloprim used together with azathioprine or 6–MP has similar effect as having reduced TPMT activity, causing increased accumulation of the 6–MP metabolite that is toxic to the bone marrow.

6–MP metabolite levels

In addition to monitoring blood cell counts and liver tests, doctors also may measure blood levels of the chemicals that are formed from 6–MP (6–MP metabolites), which can be helpful in several situations such as:

1. If a patient's disease is not responding to standard doses of 6–MP or azathioprine and his/her 6–MP blood metabolite levels are low, doctors may increase the 6–MP or azathioprine dose.

2. If a patient's disease is not responding to treatment and his/her 6–MP blood metabolite levels are zero, he/she is not taking his/her medication. The lack of response in this case is due to patient non–compliance.

Duration of treatment with azathioprine and 6–MP

Patients have been maintained on 6–MP or azathioprine for years without important long–term side effects. Patients on long–term azathioprine or 6–MP, however, should be closely monitored by their doctors. There are data suggesting that patients on long–term maintenance fare better than those who stop these medications. Thus, those who stop azathioprine or 6–MP are more likely to experience recurrence of their disease and are more likely to need corticosteroids or undergo surgery.

Infliximab (Remicade)

Infliximab (Remicade) is an antibody that attaches to a protein called tumor necrosis factor–alpha (TNF–alpha). TNF–alpha is one of the proteins produced by immune cells during activation of the immune system. TNF–alpha, in turn, stimulates other cells of the immune system to produce and release other proteins that promote inflammation. In Crohn's disease, there is continued production of TNF–alpha as part of the immune activation. Infliximab, by attaching to TNF–alpha, blocks its activity and in so doing decreases the inflammation.

Infliximab, an antibody to TNF–alpha, is produced by the immune system of mice after the mice are injected with human TNF–alpha. The mouse antibody then is modified to make it look more like a human antibody, and this modified antibody is infliximab. Such modifications are necessary to decrease the likelihood of allergic reactions when the antibody is administered to humans. Infliximab is given by intravenous infusion over two hours. Patients are monitored throughout the infusion for adverse reactions.

In August 1998 the United States Food and Drug Administration approved the use of infliximab for the short–term treatment of moderate to severe Crohn's disease patients who respond inadequately to corticosteroids, azathioprine, or 6–MP.

Effectiveness of infliximab

Infliximab is an effective and fast–acting drug for the treatment of active Crohn's disease. In a study involving patients with moderate to severe Crohn's disease who were not responding to corticosteroids or immuno–modulators, 65% experienced improvement in their disease after one infusion of infliximab. Some patients noticed improvement in symptoms within days of the infusion. Most patients experienced improvement within two weeks.

In patients who respond to infliximab, the improvements in symptoms can be dramatic. Moreover, there can be impressively rapid healing of the ulcers and the inflammation in the intestines after just one infusion.

The anal fistulae of Crohn's disease are troublesome and often difficult to treat. Infliximab has been found to be effective for treating fistulae.

Duration of benefits with infliximab

The majority of the patients who responded to a first infusion of infliximab developed recurrence of their disease within three months. However, studies have shown that repeated infusions of infliximab every eight weeks are safe and effective in maintaining remission in many patients over a one to two year period. Response to infliximab after repeated infusions sometimes is lost if the patient starts to develop antibodies to the infliximab (which attach to the infliximab and prevent it from working). Studies are now being done to determine the long–term safety and effectiveness of repeated infusions of infliximab.

One potential use of infliximab is to quickly control active and severe disease. The use of infliximab then may be followed by maintenance treatment with azathioprine, 6–MP or 5–ASA compounds. Azathioprine or 6–MP also may be helpful in preventing the development of antibodies against infliximab.

Side effects of infliximab

Infliximab generally is well–tolerated. There have been rare reports of side effects during infusions, including chest pain, shortness of breath, and nausea. These effects usually resolve spontaneously within minutes if the infusion is stopped. Other commonly–reported side effects include headache and upper respiratory tract infection.

TNF–alpha is an important protein for defending the body against infections. Infliximab, like immuno–modulators, increases the risk for infection. One case of salmonella colitis and several cases of pneumonia have been reported with the use of infliximab. There also have been cases of tuberculosis (TB) reported after the use of infliximab.

Because infliximab is partly a mouse protein, it may induce an immune reaction when given to humans, especially with repeated infusions. In addition to the side effects that occur while the infusion is being given, patients also may develop a "delayed allergic reaction" that occurs 7–10 days after receiving the infliximab. This type of reaction may cause flu–like symptoms with fever, joint pain and swelling, and a worsening of Crohn's disease symptoms. It can be serious, and if it occurs, a physician should be contacted. Paradoxically, those patients who have more frequent infusions of infliximab are less likely to develop this type of delayed reaction compared to those patients who receive infusions separated by long intervals (6–12 months). Although infliximab is only FDA approved for a single infusion at this time, patients should be aware that they are likely to require repeated infusions once Remicade therapy has been initiated.

Rare cases of nerve inflammation such as optic neuritis (inflammation of the nerve of the eye) and mother neuropathy has been reported with the use of infliximab.

Precautions with infliximab

Infliximab can aggravate and cause the spread of an existing infection. Therefore, it should not be given to patients with pneumonia, urinary tract infection or abscess (localized collection of pus). It now is recommended that patients be tested for TB prior to receiving infliximab. Patients who previously had TB should inform their physician of this before they receive infliximab infliximab can cause the spread of cancer cells; therefore, it should not be given to patients with cancer.

Infliximab can promote intestinal scarring (part of the process of healing) and, therefore, can worsen strictures (narrowed areas of the intestine caused by inflammation and subsequent scaring) and lead to intestinal obstruction. It also can cause partial healing (partial closure) of anal fistulae. Partial closure of fistulae impedes drainage of fluid through the fistulae, and may result in collections of fluid in which bacteria multiply, which can result in abscesses.

The effects infliximab on the fetus are not known.

Because infliximab is partly a mouse protein, some patients can develop antibodies against infliximab with repeated infusions. Such antibodies can decrease the effectiveness of the drug. The chance of developing such antibodies can be decreased by the concomitant use of 6–MP and corticosteroids. There are some reports of worsening heart disease in patients who have received Remicade. The precise mechanism and role of infliximab in the development of this side effect is unclear. As a precaution, individuals with heart disease should inform their physician of this condition before receiving infliximab.

While infliximab represents an exciting new class of medications in the fight against Crohn's disease, caution is warranted in its use. The long–term safety and effectiveness is not yet known.

Adalimumab (Humira)

Adalimumab is an anti–TNF agent similar to infliximab and decreases inflammation by blocking tumor necrosis factor (TNF–alpha). In contrast to infliximab, adalimumab is a fully humanized anti–TNF antibody (no mouse protein). Adalimumab is administered subcutaneously (under the skin) instead of intravenously as in the case of infliximab.

Rheumatologists have been using adalimumab for treating inflammation of the joints in patients with rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis. Four recent clinical trials (involving almost 1,500 patients) comparing adalimumab to placebo, have demonstrated that adalimumab is also effective in treating inflammation in the intestines of patients with Crohn's disease and in reducing signs and symptoms of Crohn's disease.

Adalimumab is comparable to infliximab in effectiveness and safety for inducing and maintaining remission in patients suffering from Crohn's disease. Adalimumab is also effective in healing Crohn's anal fistulas. Adalimumab has been shown to be effective for patients who either failed or cannot tolerate infliximab.

The Food and Drug Administration in February 2007, approved Humira (adalimumab) to treat adult patients with moderately to severely active Crohn's disease. Adalimumab (Humira) is administered subcutaneously every two weeks.

The side effects of Adalimumab

Adalimumab generally is well–tolerated. The most common side effect is skin reactions at the site of injection with swelling, itching, or redness. Other common side effects include upper respiratory infections, sinusitis, and nausea.

TNF–alpha is an important protein for defending the body against infections. Adalimumab, like infliximab, increases the risk of infection. There have been cases of tuberculosis (TB) reported after the use of infliximab and adalimumab. It now is recommended that patients be tested for TB prior to receiving these agents. Patients who previously had TB should inform their physician of this before they receive these agents. Adalimumab, like infliximab, can aggravate and cause the spread of an existing infection. Therefore, it should not be given to patients with pneumonia, urinary tract infection or abscess (localized collection of pus).

Rare cases of lymphoma (cancer of the lymphatic system) have been reported with the use of adalimumab. Rare cases of nervous system inflammation have been reported with the use of adalimumab. The symptoms may include numbness and tingling, vision disturbances, weakness in legs. Some patients receiving adalimumab may rarely develop symptoms that mimic systemic lupus; these symptoms include skin rash, arthritis, chest pain, or shortness of breath. These lupus–like symptoms resolve after stopping the drug.

There are some reports of worsening heart disease such as heart failure in patients who have received infliximab or adalimumab. The precise mechanism and role of these agents in the development of this side effect is unclear. As a precaution, individuals with heart disease should inform their physician of this condition before receiving infliximab or adalimumab.

Severe allergic reactions with rash, difficulty breathing, and severe low blood pressure or shock are rare, but serious allergic reactions can occur either after the fist injection or after many injections. Patients experiencing symptoms of serious allergic reactions should seek emergency care are immediately.

Methotrexate (Rheumatrex, Trexall)

Methotrexate (Rheumatrex, Trexall) is both an immuno–modulator and antiinflammatory medication. Methotrexate has been used for many years in the treatment of severe rheumatoid arthritis and psoriasis. It has been helpful in treating patients with moderate to severe Crohn's disease who are either not responding to azathioprine and 6– MP or are intolerant of them. Methotrexate also may be effective in patients with moderate to severe ulcerative colitis who are not responding to corticosteroids, azathioprine, or 6–MP. It can be given orally or by weekly injections under the skin or into the muscles, but it is more reliably absorbed with the injections.

One major complication of methotrexate is the development of liver cirrhosis when the medication is given over a prolonged period of time (years). The risk of liver damage is higher in patients who also abuse alcohol or are severely obese. Although it has been recommended that a liver biopsy should be obtained in patients who have received a cumulative (total) methotrexate dose of 1.5 grams or higher, the need for such biopsies is controversial.

Other side effects of methotrexate include low white blood cell counts and inflammation of the lungs.

Methotrexate should not be used in pregnant women because of toxic effects on the fetus.

Surgery in Crohn's disease

There is no surgical cure for Crohn's disease. Even when all of the diseased parts of the intestines are removed, inflammation frequently recurs in previously healthy intestines months to years after the surgery. Therefore, surgery in Crohn's disease is used primarily for:

1. Removal of a diseased segment of the small intestine that is causing obstruction.

2. Drainage of pus from abdominal and peri–rectal abscesses.

3. Treatment of severe anal fistulae that do not respond to drugs.

4. Resection of internal fistulae (such as a fistula between the colon and bladder) that are causing infections.

Usually, after the diseased portions of the intestines are removed surgically, patients can be free of disease and symptoms for some time, often years. Surgery, when successfully performed, can lead to a marked improvement in a patient's quality of life. In many patients, however, Crohn's disease eventually returns, affecting previously healthy intestines. The recurrent disease usually is located at or near the previous site of surgery. In fact, 50% of patients can expect to have a recurrence of symptoms within four years of surgery. Drugs such as Pentasa or 6–MP have been useful in some patients to reduce the chances of relapse of Crohn's disease after surgery.

General measures

General measures which may help control Crohn's disease include dietary changes and supplementation. Since fiber is poorly digestible, it can worsen the symptoms of intestinal obstruction. Hence, a low fiber diet may be recommended, especially in those patients with small intestinal disease. A liquid diet may be of benefit when symptoms are more severe. Intravenous nutrition or TPN (total peripheral nutrition) may be utilized when it is felt that the intestine needs to "rest." Supplementation of calcium, folate and vitamin B12 is helpful when malabsorption of these nutrients is apparent. The use of anti–diarrheal agents [diphenoxylate and atropine (Lomotil), loperamide (Imodium)] and anti–spasmotics also can help relieve symptoms of cramps and diarrhea.

Conclusions

Crohn's disease is a chronic inflammatory disease involving predominantly the small intestine and colon. The symptoms and the activity of the disease can come and go. Even though many effective medications are available to control the activity of the disease, there is as yet no cure for Crohn's disease. Surgery can significantly improve the quality of life in selected individuals, but recurrence of the disease after surgery is common. The disease can have complications, both within and outside of the intestine. Newer treatments are actively being evaluated. A better understanding of the role of genetics and environmental factors in the cause of Crohn's disease may lead to improved treatments and prevention of the disease.

Crohn's Disease At A Glance

• Crohn's disease is a chronic inflammatory disease of the intestines.
  
  
• The cause of Crohn's disease is unknown.
  
  
• Crohn's disease can cause ulcers in the small intestine, colon, or both.
  
  
• Abdominal pain, diarrhea, vomiting, fever, and weight loss are symptoms of Crohn's disease.
  
  
• Crohn's disease of the small intestine may cause obstruction of the intestine.
  
  
• Crohn's disease can be associated with reddish, tender skin nodules, and inflammation of the joints, spine, eyes, and liver.
  
  
• The diagnosis of Crohn's disease is made by barium enema, barium x–ray of the small bowel, and colonoscopy.
  
  
• The choice of treatment for Crohn's disease depends on the location and severity of the disease.
  
  
• Treatment of Crohn's disease includes drugs for suppressing inflammation or the immune system, antibiotics, and surgery.