Crohn's Disease


Crohn’s disease is an inflammatory bowel disease, the general name for conditions that cause inflammation and swelling of the intestines.  It is an ongoing disorder that can affect any area of the digestive tract, (also referred to as the gastrointestinal or GI tract) from the mouth to the anus.  However, it most commonly affects the lower part of the small intestine, called the ileum. The inflammation it causes can extend deep into the wall of the affected portions of the digestive tract leading to swelling and scar formation which can cause symptoms such as diarrhea and pain.

The symptoms of Crohn’s disease are similar to other intestinal disorders, such as irritable bowel syndrome and ulcerative colitis so it can be difficult to diagnose.  Ulcerative colitis is a different inflammatory bowel disease.  It causes inflammation and ulcers of only the innermost layer of the wall of the bowel and only affects the large intestine.  In Crohn’s disease, the inflammation can involve all three layers of the wall of the intestine; and can affect any portion of the entire digestive tract.  It can also involve more than one area separated by segments of normal healthy bowel between them.  Irritable Bowel Syndrome is a disorder of both coordination of bowel muscles and bowel sensation; but does not cause inflammation

Crohn’s disease affects men and women equally, and seems to run in some families.  About 20 percent of people with Crohn’s disease have a blood relative with some form of inflammatory bowel disease, most often a brother or sister and sometimes a parent or child.  Crohn’s disease can occur in people of all age groups; but it is more often diagnosed in people between the ages of 20 and 30. People of Jewish heritage have an increased risk of developing Crohn’s disease, and African Americans are at decreased risk for developing Crohn’s disease.

Crohn’s disease may also be called ileitis or enteritis.


Several theories exist about what causes Crohn’s disease, but none have been proven. The human immune system is made from cells and different proteins that protect people from infection. The most popular theory is that the body’s immune system reacts abnormally in people with Crohn’s disease, mistaking bacteria, foods, and other substances for being foreign.  The immune system’s response is to attack these “invaders.”  During this process, white blood cells accumulate in the lining of the intestines, producing chronic inflammation, which leads to ulcerations and bowel injury.

Scientists do not know if the abnormality of the immune system function in people with Crohn’s disease is a cause, or a result, of the disease.  Research shows that the inflammation seen in the GI tract of people with Crohn’s disease involves several factors including the genes the patient has inherited, the immune system itself, and the environment.  Foreign substances, also referred to as antigens, are found in the environment.  Possible causes for inflammation may be the body’s reaction to these antigens, or the antigens themselves may be the cause for the inflammation.

We know that bowel inflammation is controlled by a number of genes which seem to regulate the body’s production of both pro-inflammatory chemicals and anti-inflammatory chemicals.  Several genes have been identified as possibly playing a role in Crohn’s; but they are not found in everyone with the condition.  One of these regulatory proteins produced by the immune system, called tumor necrosis factor (TNF), appears to stimulate the inflammation of Crohn’s disease in some patients.  Several newer medications designed to treat Crohn’s are directed against this protein.


Crohn’s can cause very wide range of symptoms that can vary in both type and severity.  The most common symptoms are abdominal pains (often in the lower right area of the abdomen); and diarrhea.  Rectal bleeding, weight loss, arthritis, skin problems, and fever may also occur.  Bleeding may be serious or slow and persistent leading to anemia.  Children with Crohn’s disease may suffer delayed development and stunted growth.

How is Crohn’s disease diagnosed?

The diagnosis of Crohn’s disease is usually based on a combination of a discussion of symptoms, a thorough physical exam, possible blood tests, and more specific tests designed to look at the intestine more closely.

Blood tests may be done to check for anemia, which could indicate bleeding in the intestines.  Blood tests may also uncover a high white blood cell count, which is a sign of inflammation somewhere in the body.  By testing a stool sample, the doctor can tell if there is bleeding or infection in the intestines.  Other blood tests can be done to evaluate the liver and kidneys.

The doctor will also need to consider choosing from a number of different tests designed to give more specific information about the appearance of the intestines.  An upper GI series is an X-ray designed to look at the small intestine.  For this test, the person drinks a barium solution that coats the lining of the small intestine, It shows up white on x-ray film, and can reveal inflammation or other abnormalities in the intestine. If these tests show Crohn’s disease, more x rays of both the upper and lower digestive tract may be necessary to see how much of the GI tract is affected by the disease.   More specialized images of the digestive tract can be obtained from a CT (computerized x-ray) of the small bowel or an MRI of the small bowel.

The small bowel can also be inspected remotely with a procedure called Pill Camera Endoscopy in which a small camera the size of a vitamin pill is swallowed.  It travels through the intestine sending pictures to a radio receiver harness worn over the abdomen.  

More specific and more accurate information can be obtained with tests done by inserting steerable flexible tubes into the digestive system. These allow closer directed inspection and also allow the doctor to take small samples of the lining of the digestive tract (a biopsy) for microscopic analysis. 

Tests to inspect the colon include either a sigmoidoscopy or a colonoscopy in which the doctor inserts a flexible, lighted tube into the anus.  A sigmoidoscopy allows the doctor to examine the lining of the lowest part of the large intestine; while a colonoscopy allows the doctor to examine the lining of the entire large intestine and the very end of the small intestine.  

The small bowel can now also be inspected with a relatively new test called balloon enteroscopy that uses a different kind of flexible tube.  It can be inserted through the mouth or anus to allow direct inspection of much larger portions of the small intestine than could ever be seen before.  Another test to examine the small bowel is call small bowel capsule study. This entails swallowing a small capsule that takes pictures of the small bowel and transmits the images to a recording box that the patient wears for 8 hours.

The doctor will choose from all these available tests based on your individual symptoms, lab tests, and findings on physical exam. All these tube tests allow the doctor to look for areas of inflammation, look for bleeding, and take biopsies if necessary.

What are the complications of Crohn’s disease?

The most common complication is blockage of the intestine.   Blockage occurs when inflammation causes swelling or scarring that narrows the intestinal passageway.  Crohn’s disease may also cause sores or ulcers that tunnel through the affected area into surrounding tissues, such as the bladder, vagina, other areas of intestine, or skin. The areas around the anus and rectum can also be involved.  The tunnels, called fistulas, are a common complication for some people and can become infected. Sometimes fistulas can be treated with medicine; but in some cases they may require surgery.  In addition to fistulas, small shallow tears called fissures may develop in the lining of the anal passageway.

Nutritional complications are common in Crohn’s disease.  Deficiencies of proteins, calories, and vitamins are well documented. These deficiencies may be caused by inadequate dietary intake, intestinal protein loss, or poor absorption, (referred to as malabsorption).  Treating the inflammation usually helps correct these deficiencies.

Other less common complications associated with Crohn’s disease include specific types of arthritis, certain skin problems, inflammation in the eyes or mouth, kidney stones, gallstones, and conditions affecting the liver and bile duct system.  Some of these problems resolve during treatment for disease of the digestive system, but some must be treated separately.


Treatment may include drugs, nutrition supplements, surgery, or a combination of these options. The goals of treatment are to control inflammation, correct nutritional deficiencies, and relieve symptoms like abdominal pain, diarrhea, and rectal bleeding. At this time, treatment can help control the disease.   The goal of treatment is to restore the lining of the digestive tract back to normal and  lower the number of times a person experiences a recurrence of the inflammation.   However, there is no cure.  Treatment for Crohn’s disease depends on the location and severity of disease, complications, and the previous responses to medical treatments.

Some people have long periods of remission, sometimes years, when they are free of symptoms.  However, the disease usually recurs at various times over a person’s lifetime.  This changing pattern of the disease means one cannot always tell when a treatment has helped.  Predicting when a remission may occur or when symptoms will return is not possible.

Someone with Crohn’s disease may need medical care for a long time, with regular doctor visits to monitor the condition.

Drug therapy

Anti-Inflammation Drugs:

Most people are first treated with drugs containing mesalamine, a substance that helps control inflammation.  Sulfasalazine is the original drug of this family.  Patients who do not benefit from it or who cannot tolerate it may be put on other mesalamine-containing drugs, generally known as 5-ASA agents, such as Apriso, Lialda, Dipentum, Colazal, or Pentasa.  Possible side effects of mesalamine-containing drugs include nausea, vomiting, heartburn, diarrhea, and headache; but they are uncommon.  

Cortisone or Steroids:

Cortisone drugs and steroids—called corticosteroids—provide very effective results.  They are naturally occurring chemicals produced every day in our adrenal glands.  The amounts are small and they are necessary for life.  In larger amounts, however, they are excellent anti-inflammatory agents.  Prednisone is a common generic name of one of the drugs in this group of medications.  In the beginning, when the disease is at its worst, prednisone is often prescribed in a large enough dose to suppress the inflammation.  The dosage is then lowered once symptoms have been controlled because these drugs can cause serious side effects such as greater susceptibility to infection, elevated blood pressure, and bone thinning.  There are newer steroids (Entocort and Uceris) that work in a similar fashion as prednisone, but have less side effects.

Immune modulators:

Drugs that modify the immune system are also used to treat Crohn’s disease. The most commonly prescribed are azathioprine (Imuran) and 6-mercaptopurine (Purinethol).  Immune modulators work by blocking the overactive immune reaction that contributes to inflammation.  These drugs may cause side effects like nausea, vomiting, and diarrhea and may lower a person’s resistance to infection.  Some studies suggest that immunosuppressive drugs may enhance the effectiveness of corticosteroids.  When patients are treated with both, the dose of corticosteroids may eventually be lowered or stopped.

“Biologics" such as Infliximab (Remicade), Adalimumab (Humira), Certolizumab (Cimzia), Natalizumab (Tysabri) and Vedolizumab (Entyvio):

This is a group of chemicals purposely designed to attack and block specific chemicals (like tumor necrosis factor or circulating lymphocytes) or steps in the process causing bowel inflammation.  Infliximab (Remicade) was the first of this group of medications to be approved by the U.S. Food and Drug Administration for the treatment of moderate to severe Crohn’s disease that had not responded to standard therapies (mesalamine substances, corticosteroids, immunosuppressive agents) and for the treatment of open, draining fistulas.  All the biologics share similar side effects such as increased risk of specific infections.  Additional research is underway to fully understand the best way to use these newer treatments as well as to design even newer and more effective agents.   The Oregon Clinic is actively involved in a number of these nationwide projects. 


Antibiotics are used to treat bacterial overgrowth in the small intestine caused by stricture, fistulas, or prior surgery. For this common problem, the doctor may prescribe one or more of the following antibiotics: ampicillin, a sulfonamide, cephalosporins, tetracycline, Ciprofloxicin, or metronidazole.

Anti-Diarrheals and Fluid Replacements:

Diarrhea and crampy abdominal pain are often relieved when the inflammation subsides, but additional medication may also be necessary.  Several antidiarrheal agents could be used, including diphenoxylate (Lomotil), loperamide (Immodium), and codeine.  Patients who are dehydrated because of diarrhea will be treated with fluids and electrolytes.

Nutrition Supplementation:

The doctor may recommend nutritional supplements, especially for children whose growth has been slowed.  Special high-calorie liquid formulas are sometimes used for this purpose.  A small number of patients may need to be fed intravenously for a brief time through a small tube inserted into the vein of the arm.  This procedure can help patients who need extra nutrition temporarily, those whose intestines need to rest, or those whose intestines cannot absorb enough nutrition from food.  

There are no known foods that cause Crohn’s disease.  However, when people are suffering a flare in disease, foods such as bulky grains, hot spices, alcohol, and milk products may increase diarrhea and cramping.


A number of patients with Crohn’s disease will require surgery at some point in their lives.  It becomes necessary when medications can no longer control symptoms.  Surgery is used either to relieve symptoms that do not respond to medical therapy or to correct complications such as blockage, perforation, abscess, or bleeding from the intestines.  Operations to remove diseased parts of the intestine can help people with Crohn’s disease, but they are not a cure.  They do not eliminate the underlying factors that caused the disease.  Therefore, it is not uncommon for people with Crohn’s Disease to have more than one operation, because the inflammation tends to return to the area next to the area where the diseased intestine was removed.  

Surgeons make every effort to remove only the diseased section of intestine.  In this operation, the intestine is cut above and below the diseased area and then the ends reconnected.

Some people who have Crohn’s disease in the large intestine need to have their entire colon removed in an operation called a colectomy.   In this case, a small opening is made in the front of the abdominal wall, and the end of the small intestine (the ileum) is brought to the skin’s surface.  This opening, called a stoma, is where waste exits the body.  It is about the size of a quarter and is usually located in the right lower part of the abdomen near the beltline.  A pouch is worn over the opening to collect waste, and the patient empties the pouch as needed. The majority of colectomy patients go on to live normal, active lives including a very noted Crohn’s patient who continued to play professional football after his surgery.

Because Crohn’s disease often recurs after surgery, people considering it should carefully weigh its benefits and risks compared with other treatments.  Surgery may not be appropriate for everyone.  People faced with this decision should get as much information as possible from doctors, from nurses who work with colon surgery patients (enterostomal therapists), and from other patients.  National advocacy organizations can suggest local support groups and other information resources.

People with Crohn’s disease may feel well and be free of symptoms for substantial spans of time when their disease is not active. Despite the need to take medication for long periods of time and occasional need for hospitalizations, most people with Crohn’s disease are able to hold jobs, raise families, and function successfully at home and in society.


Research has shown that the course of pregnancy and delivery is usually not impaired in women with Crohn’s disease.  Even so, women with Crohn’s disease should discuss the matter with their doctors before pregnancy. Since the most important factor in achieving a successful pregnancy is control of the Crohn’s inflammation it often suggested that patients continue their Crohn’s medication during the pregnancy.   Your obstetrician will work closely with your gastroenterologist to address these issues.  Most children born to women with Crohn’s disease are unaffected.  However, children who do get the disease are sometimes more severely affected than those who get the disease as an adult.  This can result in slowed growth and delayed sexual development in some cases.

There is no evidence showing that stress causes Crohn’s disease.  However, people with Crohn’s disease sometimes feel increased stress in their lives from having to live with a chronic illness.  Some people with Crohn’s disease also report that they experience a flare in disease when they are experiencing a stressful event or situation.  There is no type of person that is more likely to experience a flare in disease than another when under stress.  For people who find there is a connection between their stress level and a worsening of their symptoms, using relaxation techniques, such as slow breathing, and taking special care to eat well and get enough sleep, may help them feel better.

People with Crohn’s disease often experience a decrease in appetite which can affect their ability to receive the daily nutrition needed for good health and healing. In addition, Crohn’s disease is associated with diarrhea and poor absorption of necessary nutrients. No special diet has been proven effective for preventing or treating Crohn’s disease, but it is very important that people who have Crohn’s disease follow a nutritious diet and avoid any foods that seem to worsen their symptoms. There are no consistent dietary rules to follow that will improve everybody’s symptoms.

People should take vitamin supplements only on their doctor’s advice.


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