- Crohn's disease definition and facts
- What is Crohn's disease?
- What does Crohn's disease look like (pictures)?
- What are the symptoms of Crohn's disease?
- What causes Crohn's disease?
- What are the differences between Crohn's disease and ulcerative colitis?
- How does Crohn's disease affect the intestines?
- Is there a test for diagnosing Crohn's disease?
- Is there a special diet for Crohn's disease? Are there special vaccination recommendations?
- Crohn's disease treatment medications
- Anti-inflammatory medications for Crohn's disease
- 5-ASA oral and rectal medications for Crohn's disease
- Corticosteroids for Crohn's disease
- Antibiotics for Crohn's disease
- Immuno-modulator medications
- Infliximab (Remicade)
- Adalimumab (Humira), Certolizumab pegol (Cimzia), Natalizumab (Tysabri)
- Vedolizumab (Entyvio), Ustekinumab (Stelara), Methotrexate (Rheumatrex,Trexall)
- 5-ASA (mesalamine) oral medications for Crohn's disease
- Biosimilar medications for Crohn's disease
- Surgery in Crohn's disease
- What are the complications of Crohn's disease?
- What is the prognosis and life expectancy for Crohn's disease?
Crohn's disease definition and facts
- Crohn's disease is a chronic inflammatory disease of the gastrointestinal (digestive, GI) tract.
- Symptoms of Crohn’s disease include:
- The cause of Crohn's disease is unknown.
- Crohn’s disease is not contagious. You cannot “get” it from another person.
- Diet can affect and trigger Crohn’s disease flare-ups; however, it is doubtful that diet causes the disease.
- Researchers and doctors do not know the cause of Crohn’s disease; however, some suspect that the cause is due to certain bacteria, for example, mycobacterium.
- Crohn's disease can cause ulcers in the small intestine, colon, or both. The disease also may cause obstruction of the small intestine.
- Associated sign and symptoms of Crohn's disease include reddish, tender skin nodules, and inflammation of the joints, spine, eyes, and liver.
- Crohn’s disease and ulcerative colitis (another chronic inflammatory condition of the colon) are a type of inflammatory bowel disease (IBD).
- 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 5-ASA compounds and corticosteroids, topical antibiotics, immunomodulators, and biosimilars drugs for suppressing inflammation or the immune system; antibiotics, and surgery.
- Complications of Crohn’s disease include megacolon and rupture of the intestine, painful eye conditions, arthritis, inflammation of the low back and spine, hepatitis, cirrhosis, jaundice, and cancer.
- Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) are two different problems with the digestive tract (gastrointestinal, GI).
What is Crohn's disease?
Crohn's disease (sometimes called Crohn disease) is a chronic inflammatory disease of the intestines. It primarily causes ulcerations (breaks in the mucosal 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 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).
Men and women are affected equally by inflammatory bowel disease. Americans of Jewish European descent are more likely to develop IBD than the general population. IBD has historically been considered predominately a disease of Caucasians, but there has been an increase in the reported cases in African Americans. The prevalence appears to be lower among Hispanic and Asian populations. IBD most commonly begins during adolescence and early adulthood (usually between the ages of 15 and 35). There is a small second peak of newly diagnosed cases after age 50. The number of new cases (incidence) and number of cases (prevalence) of Crohn's disease in the United States are rising, although the reason for this is not completely understood.
Crohn's disease tends to be more common in relatives of patients with Crohn's disease. If a person has a relative with the disease, his/her risk of developing the disease is estimated to be at least 10 times that of the general population and 30 times greater if the relative with Crohn's disease is a sibling. It also is more common among relatives of patients with ulcerative colitis.
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 occasionally 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:
- Crohn's colitis is inflammation that is confined to the colon. Abdominal pain and bloody diarrhea are the common symptoms. Anal fistulae and perirectal abscesses also can occur.
- Crohn's enteritis refers to inflammation confined to the small intestine (the second part, called the jejunum or the third 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.
- 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.
- Crohn's enterocolitis and ileocolitis 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 ileocolitis 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:
- Swelling of the tissue of the anal sphincter, the muscle at the end of the colon that controls defecation.
- Development of ulcers and fissures (long ulcers) within the anal sphincter. These ulcers and fissures can cause bleeding and pain with defecation.
- 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.
- Development of perirectal abscesses (collections of pus in the anal and rectal area). Peri-rectal abscesses can cause fever, pain and tenderness around the anus.
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. Crohn's disease is not contagious. Diet may affect the symptoms of Crohn's disease; however, it is unlikely that diet is responsible for causing 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 individuals with IBD the immune system is abnormally and chronically activated in the absence of any known invader. This 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 people 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.
Other genes are still being discovered and studied which are important in understanding the pathogenesis of Crohn's disease including autophagy related 16-like 1 gene (ATG 16L1) and IRGM, which both contribute to macrophage defects and have been identified with the Genome-Wide Association study. There also have been studies which show that in the intestines of individuals with Crohn's disease, there are higher levels of a certain type of bacterium, E. coli, which might play a role in the disease. One postulated mechanism by which this could occur is through a genetically determined defect in the elimination of the E. coli, by intestinal mucosal macrophages. The exact roles that these various factors play in the development of this disease remain unclear.
What are the differences between Crohn's disease and 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. The affected segment(s) of bowel in Crohn's disease often is studded with deeper ulcers with normal lining between these ulcers.
How does Crohn's disease affect the intestines?
In the early stages, Crohn's disease causes small, scattered, shallow, crater-like ulcerations (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 cause puncture holes or perforations 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 vegetable matter that plug the already-narrowed segment of the intestine. When the intestine is obstructed, 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.
Deep ulcers can cause puncture holes or perforations 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. Individuals 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.
Is there a test for diagnosing Crohn's disease?
There is no specific diagnostic test for Crohn’s disease. The diagnosis of Crohn's disease is suspected in patients with fever, abdominal pain and tenderness, diarrhea with or without bleeding, and anal diseases, such as ulcers or fissures. Laboratory blood tests may show elevated white blood 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 minerals 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. CT and MRI enterography are imaging techniques which use oral contrast agents consisting of watery solutions with or without low concentrations of barium to provide more adequate luminal distension, have been reported to be superior in the evaluation of small bowel pathology in patients with Crohn's disease.
Video capsule endoscopy (VCE) has also been added to the list of 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.) In a prospective blinded evaluation, video capsule endoscopy was demonstrated to be superior in its ability to detect small bowel pathology missed on small bowel radiographic studies and CT exams.
Video capsule endoscopy should not be performed in patients who have an obstruction of the small intestine. The capsule may become stuck at the site of obstruction and make the obstruction worse. Doctors usually also are reluctant to perform video-capsule endoscopy for the same reason in patients whom 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-moderate number of patients with pacemakers or defibrillators who have undergone video capsule endoscopy, there have been no problems.
Is there a special diet for Crohn's disease? Are there special vaccination recommendations?
Dietary changes and supplementation that may help control Crohn's disease
- Since fiber is poorly digestible, it can worsen the symptoms of intestinal obstruction. A low fiber diet for Crohn's diease 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 parenteral 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 antispasmodics also can help relieve symptoms of cramps and diarrhea.
Vaccination recommendations for individuals with Crohn's disease
They should receive a single dose of Tdap, then Td booster every 10 years.
Women between the ages of 9 and 26 should receive 3 doses of HPV vaccine (and consideration should be given to older patients who are HPV negative on Pap smear). Men in the same age range should also consider being vaccinated given the increased risk of HPV with immunosuppression.
One dose of pneumococcal vaccine should be given between age 19-26 and then revaccination after 5 years.
Other factors that may affect Crohn's disease
Osteoporosis with markedly reduced bone mineral densities has also increasingly been recognized as a significant health problem in patients with inflammatory bowel disease. Screening with a bone density study is recommended in postmenopausal woman, men over age 50, patients with prolonged corticosteroid use (more than 3 consecutive months or recurrent courses), patients with personal history of traumatic fractures with minimal trauma, and patients with hypogonadism. Most patients with inflammatory bowel disease should be taking calcium and vitamin D supplements.
Crohn's disease treatment medications
There is no medication that can cure Crohn's disease. Patients with Crohn's disease typically will experience flares, or periods of relapse (worsening of inflammation) followed by periods of remission (lessening of 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 the 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.
Anti-inflammatory agents such as 5-ASA compounds and corticosteroids, topical antibiotics, immunomodulators, and biosimilars are medications used to treat Crohn’s disease.
Selection of treatment regimens depends on disease severity, disease location, and disease-associated complications. Various guidelines recommend that approaches be sequential -- initially to induce clinical remission, and then to maintain remissions. Initial evidence of improvement should be seen within 2 to 4 weeks, and maximal improvement should be seen in 12 to 16 weeks. The classic approach to therapy in Crohn's disease has been a "step-up" approach starting with the least toxic agents for mild disease, and increasingly more aggressive treatment for more severe disease, or patients who have not responded to less toxic agents. Treatment has been moving toward a "top-down" approach (early aggressive management) which might decrease exposure to anti-inflammatory agents and increase exposure to agents that enhance mucosal healing that might prevent future complications.
Anti-inflammatory medications for Crohn's disease
Anti-inflammatory medications that decrease intestinal inflammation are similar to arthritis medications that decrease joint inflammation. Examples of types of anti-inflammatory medications used in the treatment of Crohn's disease are:
- 5 aminosalicylic acid (5-ASA) compounds, for example, sulfasalazine (Azulfidine) and mesalamine (Pentasa, Asacol, Dipentum, Colazal, Rowasa enema, Canasa suppository).
- 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.
- Topical corticosteroids, for example, budesonide (Entocort EC). This class of corticosteroids has fewer side effects than systemic corticosteroids, which are absorbed into the body.
- Antibiotics that decrease inflammation, for example, metronidazole (Flagyl) and ciprofloxacin (Cipro).
5-ASA oral and rectal medications for Crohn's disease
5-aminosalicylic acid (5-ASA), also called mesalamine, is similar chemically to aspirin. Aspirin is an anti-inflammatory drug that 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 may even worsen the inflammation. Recent studies suggest that aspirin might actually decrease future risk of developing colorectal cancer in the general population.
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, most patients with Crohn's disease involving both the ileum (distal small intestine) and colon, must take 5-ASA 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) 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.
Most of the side effects of sulfasalazine 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.
Some 5-ASA compounds, for example, mesalamine (Asacol and Pentasa), do not have the sulfapyridine component and have fewer side effects than sulfasalazine, and are used more frequently for treating Crohn's disease and ulcerative colitis.
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.
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. 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.
Olsalazine (Dipentum) is a capsule filled with a drug 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, some patients experience diarrhea when taking olsalazine. Because of this, olsalazine is not often used.
Balsalazide (Colazal) is a capsule in which the 5-ASA is linked by a chemical bond to another molecule that is inert (without an 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 split 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 inflammation predominantly localized to the colon.
Side effects of oral 5-ASA compounds
- The 5-ASA compounds have fewer side effects than Azulfidine and 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.
- Rarely, kidney and lung inflammation has been reported with the use of 5-ASA compounds. 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 and is used in treating Crohn's disease in which there is inflammation in and near the rectum. 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.
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 for Crohn's disease
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 anti-inflammatory medications. After absorption, corticosteroids exert prompt anti-inflammatory 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 usually are well tolerated with few and mild side effects. Examples of side effects of short-course corticosteroids include
- rounding of the face (moon face),
- increased body hair,
- weight gain,
- high blood pressure,
- increased susceptibility to infections,
- muscle weakness,
- mood swings,
- personality changes,
- irritability, and
- thinning of the bones (osteoporosis) with fractures of the spine.
Children receiving corticosteroids experience stunted growth.
Long-term use of high doses of corticosteroids usually produces predictable and potentially serious side effects for example, stunted growth in children, aseptic necrosis of the hip joints, and osteoporosis.
Budesonide (Entocort EC)
Budesonide (Entocort EC) is another form of corticosteroid used for treating Crohn's disease. Like the systemic corticosteroids, budesonide is a potent anti-inflammatory medication. Unlike systemic corticosteroids, budesonide acts only via direct contact with the inflamed tissues (topically) and not systemically.
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 systemic 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 also is 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. As most budesonide is released in the terminal ileum, it will have its best results in Crohn's disease limited to the terminal ileum.
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) 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 might have some activity in the treatment of 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) is another antibiotic used in the treatment of Crohn's disease. It can be used in combination with metronidazole.
Immuno-modulator drugs 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, MTX, Mexate),
- infliximab (Remicade),
- adalimumab (Humira),
- certolizumab (Cimzia), and
- natalizumab (Tysabri).
Azathioprine (Imuran, Azasan)
Azathioprine (Imuran, Azasan) 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. 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 as valuable drugs in treating Crohn's disease and ulcerative colitis. A majority of patients with moderate to severe disease will benefit from these drugs. Azathioprine and 6-MP are used primarily in the following situations:
- Severe Crohn's disease and ulcerative colitis not responding to corticosteroids.
- The presence of undesirable corticosteroid-related side effects.
- Corticosteroid dependency, a condition in which patients are unable to discontinue corticosteroids without developing relapses of their disease.
- Maintenance of remission.
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).
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.
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 to 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-marrow 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-marrow 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.
The U.S. Food and Drug Administration recommends doctors check TPMT levels prior to starting treatment with 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.
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. Also, hepatotoxicity in the presence of normal TPMT levels has been reported. All patients taking 6-MP or azathioprine (regardless of TPMT genetics) have to be closely monitored by periodic blood counts and liver enzyme tests for as long as the medication is taken.
Allopurinol (Zyloprim), used in treating high blood uric acids levels, can induce bone marrow toxicity when used together with azathioprine or 6-MP. Allopurinol (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 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;
- 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 significant 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 is approved for the short-term treatment of moderate to severe Crohn's disease patients who respond inadequately to corticosteroids, azathioprine, or 6-MP.
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 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 immunomodulators, 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.
More recently, a rare form lymphoma called hepatosplenic T-cell lymphoma has been described associated with azathioprine therapy for Crohn's disease either alone or in combination with infliximab. Although there is not much known about this disease, it appears to be aggressive and poorly responsive to treatment.
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 to 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).
Rare cases of nerve inflammation such as optic neuritis (inflammation of the nerve of the eye) and motor neuropathy also have been reported with the use of infliximab.
Infliximab can aggravate and cause the spread of an existing infection. It should not be given to patients with pneumonia, urinary tract infections, or abscess (localized collection of pus). It 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 also can cause the spread of cancer cells and it should not be given to patients with cancer.
Infliximab can promote intestinal scarring (part of the process of healing) and 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 of infliximab on the fetus are not known, although the literature suggests this medication is safe for women to continue until week 32 of pregnancy. At that time, the risk of exposure of the fetus to this medication via placental transfer is increased. Infliximab is listed as a pregnancy category B drug by the FDA (meaning that animal studies show no increased risk, but there are no human studies).
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 infliximab (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.
The long-term safety and effectiveness is not yet known although recent 10 year data from patients who received at least 1 dose of infliximab for CD showed the safety profile similar to what was previously known. In that data set, the treated patients seemed to have an increased risk of developing infections, infusion reactions, autoimmune reactions, and malignancy.
Adalimumab (Humira), Certolizumab pegol (Cimzia), Natalizumab (Tysabri)
- Humira (adalimumab) is used to treat adult patients with moderately to severely active Crohn's disease. Adalimumab (Humira) is an anti-TNF agent similar to infliximab and decreases inflammation by blocking tumor necrosis factor (TNF-alpha).
- 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.
- Serious side effects of Humira include infections, tuberculosis, lymphoma, nervous system inflammation, lupus symptoms, worsening heart disease such as heart failure, and rarely, severe allergic reactions with rash, difficulty breathing, and severe low blood pressure or shock.
Certolizumab pegol (Cimzia)
- Certolizumab pegol (Cimzia) is used for the treatment of moderate to severe Crohn's disease in patients who do not respond sufficiently or adequately to standard medical therapy.
- Certolizumab is generally well-tolerated. Common side effects of Cimzia include runny or stuffy nose, injection site pain or other injection site reaction, upper respiratory tract infections, urinary tract infections, or a rash.
- Serious side effects of Cimzia include possible increase in the risk for serious infections including tuberculosis, worsening of heart failure, and
- hypersensitivity reactions, for example, angioedema, hives allergic dermatitis, dizziness, shortness of breath, hot flushes, low blood pressure, malaise, and fainting (syncope). Patients experiencing symptoms of severe allergic reactions should seek emergency care immediately.
- Natalizumab (Tysabri) is a humanized monoclonal antibody to alpha-4 integrin and is effective in treatment of patients with moderate to severe CD and evidence of inflammation who have not responded to aminosalicylates, antibiotics, corticosteroids, immunomodulators, or TNF inhibitors. Doctors who are registered through the CD TOUCH prescribing program may prescribe this medication to patients. Natalizumab has also been used for some forms of multiple sclerosis.
- The most common side effects reported include headache, fatigue, upper respiratory infections, and nausea. The most serious adverse events reported have been hypersensitivity, immunosuppression/infections and progressive multifocal leukoencephalopathy.
Vedolizumab (Entyvio), Ustekinumab (Stelara), Methotrexate (Rheumatrex,Trexall)
Vedolizumab (Entyvio) is a type of monoclonal antibody called an integrin receptor antagonist indicated for adults with moderate to severe ulcerative colitis (UC) or moderate to severe Crohn's disease (CD) when certain other UC or CD medicines have not worked well enough or cannot be tolerated. Entyvio may help to reduce some symptoms, achieve remission, and reduce or stop the use of corticosteroids. Entyvio works to block the movement of certain gut directed white blood cells into the gastrointestinal (GI) tract, which helps control inflammation and may reduce the symptoms of UC and CD.
The most common side effects of Entyvio include common cold symptoms (runny or stuffy nose, sinus pain, sneezing, cough), headache, joint pain, nausea, fever, infections of the nose and throat, tiredness, fatigue, upper respiratory tract infection, bronchitis, flu symptoms, back pain, rash, itching, sinus infection, sore throat, and pain in your arms or legs.
Ustekinumab (Stelara) is a human interleukin-12 and -23 antagonist indicated for the treatment of adult patients with moderately to severely active Crohn’s disease (CD) who have failed or were intolerant to treatment with immunomodulators or corticosteroids, but never failed a tumor necrosis factor (TNF) blocker; or failed or were intolerant to treatment with one or more TNF blockers. Stelara is also used to treat plaque psoriasis and psoriatic arthritis.
The most common side effects of Stelara include injection site reactions (bruising, itching, pain, redness, swelling, and hardening of the skin), cold symptoms (stuffy nose, sneezing, sore throat), headache, tired feeling, diarrhea, or skin rash or itching.
Methotrexate (Rheumatrex, Trexall)
Methotrexate (Rheumatrex, Trexall, MTX) is both an immunomodulator and anti-inflammatory 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.
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. Other serious side effects of methotrexate include low white blood cell counts and inflammation of the lungs.
5-ASA (mesalamine) oral medications for Crohn's disease
5-aminosalicylic acid (5-ASA), also called mesalamine, is similar chemically to aspirin. Aspirin is an anti-inflammatory drug that has been used for many years for treating arthritis, bursitis, and tendonitis (conditions of tissue inflammation). Aspirin is not effective in treating Crohn's disease and ulcerative colitis and may even worsen the inflammation. Studies suggest that aspirin might actually decrease future risk of developing colorectal cancer in the general population. 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.
Biosimilar medications for Crohn's disease
A biosimilar medication is a drug product that is made to be similar to another already-approved drug. It is tested to be the same as its reference drug in terms of clinical uses, effectiveness, and product safety. A biosimilar medication must meet specific strict standards to be approved by the FDA. A biosimilar is not a generic form of a drug. A generic drug contains the same compounds as the original drug, while a biosimilar drug is highly similar to the reference drug, but not identical. Examples of biosimilars are Infliximab-abda (Renflexis) and Infliximab-dyyb (Inflectra).
Infliximab-abda (Renflexis) is biosimilar to infliximab (Remicade). Renflexis is a tumor necrosis factor (TNF) blocker used to reduce:
- Signs and symptoms of Crohn’s disease and induce and maintain clinical remission in adult patients with moderately to severely active disease who have had an inadequate response to conventional therapy.
- The number of draining enterocutaneous and recto-vaginal fistulas and maintain fistula closure in adult patients with fistulizing disease.
- The signs and symptoms of Crohn’s disease in children and induce and maintain clinical remission in pediatric patients with moderately to severely active disease who have had an inadequate response to conventional therapy.
The most common side effects of Renflexis include infections (upper respiratory infection, sinus infection, throat infection, bronchitis, urinary tract infection), infusion-related reactions, headache, abdominal pain, fever or chills, cardiopulmonary reactions (chest pain, high or low blood pressure, shortness of breath), itching, hives, nausea, diarrhea, indigestion, cough, rash, fatigue, yeast infection, and joint pain.
Infliximab-dyyb (Inflectra) is biosimilar to infliximab (Remicade). Inflectra is a tumor necrosis factor (TNF) blocker used for reducing signs and symptoms of Crohn’s disease and inducing and maintaining clinical remission in adult patients with moderately to severely active disease who have had an inadequate response to conventional therapy.
Inflectra also is used to:
- Reduce the number of draining enterocutaneous and recto-vaginal fistulas and maintain fistula closure in adult patients with fistulizing disease.
- Reduce the signs and symptoms of pediatric Crohn’s disease and induce and maintain clinical remission in pediatric patients with moderately to severely active disease who have had an inadequate response to conventional therapy.
- Treat ulcerative colitis, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and plaque psoriasis.
The most common side effects of Inflectra include respiratory infections, bronchitis, sinus infections and sore throat, runny or stuffy nose, headache, coughing, stomach/abdominal pain, nausea, diarrhea, indigestion, fatigue, pain, oral thrush, joint pain, and urinary tract infection (UTI). Infusion reactions can happen up to two hours after an infusion. Symptoms of infusion reactions may include fever, chills, chest pain, low blood pressure (hypotension) or high blood pressure (hypertension), shortness of breath, rash and itching.
Serious side effects of Inflectra include serious infections, heart failure, liver injury, blood problems, nervous system disorders, allergic reactions, Lupus-like syndrome, and psoriasis.
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. Surgery in Crohn's disease is used primarily for:
- Removal of a diseased segment of the small intestine that is causing obstruction.
- Drainage of pus from abdominal and perirectal abscesses.
- Treatment of severe anal fistulae that do not respond to drugs.
- 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. When successfully performed, surgery can lead to a marked improvement in a patient's quality of life. In many patients, Crohn's disease eventually returns, affecting previously healthy intestines. The recurrent disease usually is located at or near the site of surgery. In fact, half 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.
There is accumulating evidence in favor of post-operative therapy to delay recurrence in Crohn's disease. There appears to be some benefit of mesalamine in reducing the risk of post-op recurrence for up to 3 years. A study has shown infliximab to be effective in preventing postoperative recurrence after ileocecal resection, though relapse may occur when therapy is stopped.
Treatment strategies by severity and location of disease (Based on the Second European Evidence-Based Consensus on the Diagnosis and Management of Crohn's Disease.)
Mild to Moderate Active Disease
- Commonly treated with oral mesalamine 3.2-4 g daily or sulfasalazine for ileocolonic or colonic disease as 3-6 g daily in divided doses (this approach has more recently been reported to be not very effective).
- Budesonide (9 mg/day) is effective for disease confined to ileum and/or right colon.
- Proton pump inhibitors might help with symptomatic improvement in patients with upper gastrointestinal Crohn's disease.
Moderate to Severe Disease
- Prednisone 40-60 mg/day until resolution of symptoms.
- Appropriate antibiotic therapy for infection or abscess.
- Azathioprine and 6-MP are effective for maintaining a steroid-induced remission.
- Methotrexate 25 mg/wk is effective for steroid-dependent and steroid-refractory Crohn's disease.
- Infliximab, adalimumab, and certolizumab pegol are effective in the treatment of moderate to severely active disease in patients who have not responded to adequate therapy with a steroid or immunosuppressive agent.
- Natalizumab is effective in the treatment of patients with moderate to severely active CD who have had an inadequate response or are unable to tolerate conventional Crohn's disease therapy and anti-TNF antibody therapy.
Perianal or Fistulizing Disease
- Surgical drainage for abscess
- Otherwise, treated medically with antibiotics (metronidazole), immunosuppressives, or infliximab.
What are the complications of Crohn's disease?
Complications of Crohn's disease may be related or unrelated to the inflammation within the intestine.
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 fatal 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 the bile ducts.
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 bile 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. It also is frequently complicated by the development of cancer of the bile ducts. Patients with Crohn's disease might also suffer from an increased tendency to form blood clots (hypercoagulability).
What is the prognosis and life expectancy for Crohn's disease?
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.
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Regueiro, MD, et al. "Overview of the medical management of mild to moderate Crohn disease in adults." UpToDate. Updated: Jan 24, 2018.