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.
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.
What Causes Crohn’s Disease?
Although there are many theories about what causes Crohn'sdisease, none of them have been proven. So exactly what causes it is unknown. There is a benefit, though, in understanding the possible causes of Crohn's disease and how they interact with one another. Doing so can help you better understand the symptoms, diagnosis, and treatment of Crohn's disease.
Scientists believe that Crohn's disease is caused by these factors:
- Immune system problems
- Environmental factors
How might each of these factors contribute to Crohn's disease? Read on to learn more.
How do immune system problems relate to Crohn's disease?
Scientists have linked immune system problems to inflammatory bowel disease(IBD), including Crohn's. Usually, cells of the immune system defend the body from harmful microbes -- bacteria, viruses, fungi, and other foreign substances -- that have entered your body. Your body doesn't usually respond to all microbes, however. Many microbes are helpful, especially for digestion. And so the immune system leaves them alone.
If there is an invader that needs to be eliminated, your body's defense reaction begins. This immune system response causes inflammation. Immune system cells, chemicals, and fluids flood to the site to overcome the offending substance. After the substance has been disabled or removed, the immune response ends. Inflammation subsides.
For some reason, though, people with Crohn's disease have an immune system that reacts inappropriately. The immune system may be defending the body against helpful microbes by mistake. Or, for some other reason, the inflammatory response simply will not stop. Either way, over time, this chronic inflammation in the digestive system can result in ulcers and other injuries to the intestines.
Is genetics connected to Crohn's disease?
Brothers, sisters, children, and parents of persons with IBD, including Crohn's disease, are more likely to develop the disease themselves. About 10% to 20% of people with Crohn's disease have at least one other family member who also has the disease.And the disease is more common in certain ethnic groups, such as people of Jewish descent and whites.
Is this tendency toward IBD and Crohn's disease passed genetically? Scientists have identified a gene linked to Crohn's disease. This gene helps the body decide how to react to certain microbes. If the gene has changed or mutated in some way, your body's reaction to microbes may also be different from the normal reaction. Over time, IBD or Crohn's disease may develop. People with Crohn's disease have this mutated gene twice as often as people who do not have the disease.
Do environmental factors play a role in Crohn's disease, too?
Environmental factors may help trigger Crohn's disease. These environmental factors may include any of the following:
- Substances from something you've eaten
- Microbes such as bacteria or viruses
- Cigarette smoke
- Other substances that are yet unknown
Environmental factors may contribute to Crohn's disease in one of these two ways:
- They may trigger an immune system response. Once started, the response cannot stop.
- They may directly damage the lining of the intestines. This may cause Crohn's disease to begin or to speed up.
What can I do to control Crohn's disease?
The factors involved in causing Crohn's disease are complex. Scientists continue to seek more information about the causes -- in hopes of finding better ways to diagnose, treat, and perhaps even cure this frustrating and painful disease. In the meantime, understanding current theories about the causes of Crohn's disease can help you work with your doctor to explore how various treatments might work to control this condition.
Crohn's Disease - Symptoms
The main symptoms of Crohn's disease include:
- Abdominal pain. The pain often is described as cramping and intermittent, and the abdomen may be sore when touched. Abdominal pain may turn to a dull, constant ache as the condition progresses.
- Diarrhea. Some people may have diarrhea 10 to 20 times a day. They may wake up at night and need to go to the bathroom. Crohn's disease may cause blood in stools, but not always.
- Loss of appetite.
- Fever. In severe cases, fever or other symptoms that affect the entire body may develop. A high fever may mean that you have a complication involving infection, such as an abscess.
- Weight loss. Ongoing symptoms, such as diarrhea, can lead to weight loss.
- Too few red blood cells (anemia). Some people with Crohn's disease developanemia because of low iron levels caused by bloody stools or the intestinal inflammation itself.
People with Crohn's disease also may have:
- Sores in the mouth.
- Nutritional deficiencies, such as lowered levels of vitamin B12, folic acid, iron, and fat-soluble vitamins, because the intestines may not be able to absorb nutrients from food.
- Bowel obstruction.
- Signs of disease in or around the anus. These may include:
- Abnormal tunnels or openings called fistulas that sometimes form between organs. These develop because Crohn's disease causes inflammation and ulcers in the deep layers of the intestinal wall. Fistulas may form between parts of the intestine or between the intestine and another organ such as the bladder, vagina, or skin. A fistula may be the first sign of Crohn's disease.
- Pockets of infection (abscesses).
- Small tears in the anus (anal fissures).
- Skin tags that may resemble hemorrhoids. These are caused by inflamed skin.
Crohn's Disease Complications
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 calledpyoderma 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.
There isn't one test that can tell you whether or not you have Crohn'sdisease. And Crohn's disease has many possible symptoms that are the same as symptoms for other health problems. So, to make a diagnosis of Crohn's disease, your doctor is likely to gather information from multiple sources. You'll probably go through a combination of exams, lab tests, and imaging studies with these goals in mind:
- rule out other health problems that have similar symptoms
- make a clear diagnosis of Crohn's disease
Diagnosing Crohn's disease: Physical Exam and History
Your doctor will begin by gathering information about your health history and conducting a physical exam. Findings that may indicate further tests are needed include:
- diarrhea, which may be bloody
- family history of Crohn's disease
- pain and tenderness in the abdomen
Your doctor may request lab tests in order to look for any problems that might be linked to Crohn's disease. These tests check for signs of infection, inflammation, internal bleeding, and low levels of substances such as iron, protein, or minerals. Lab tests may include:
- blood protein levels
- blood sedimentation rates
- body mineral levels
- red blood cell counts
- stool samples to check for blood or infectious microbes
- white blood cell counts
Crohn's disease may appear anywhere along the gastrointestinal tract from the mouth to the rectum. X-rays and other images can help identify the severity and location of Crohn's disease. These studies may include the following:
- barium X-rays and other X-rays
- CT scans
- colonoscopy or sigmoidoscopy
- video capsule endoscopy
A barium X-ray can show where and how severe Crohn's disease is. It is especially helpful for finding any problems in parts of the small intestine that can't be easily viewed by other techniques.
A chalky fluid containing barium is given by mouth or through the rectum. When barium fluid is given by mouth, it is called an upper GI series. When barium fluid is placed in the rectum, it is called a barium enema. The barium fluid flows through the intestines, appearing white on X-ray film. This makes it easier to view problem areas. On a barium X-ray, your doctor may be able to see ulcers, narrowed areas of the intestine, or other problems.
If barium X-rays show some sign of disease, your doctor may request other X-rays or imaging studies. These X-rays can help identify exactly how much of your digestive tract is affected by Crohn's disease.Diagnosing Crohn's Disease: CT Scans CT scanning uses computer-aided X-ray techniques to produce more detailed images of the abdomen and pelvis than can be seen in traditional X-rays. CT scans can help detect abscesses that might not show up on other X-rays. Abscesses are small pockets of infection.
- determine exactly which part of the digestive tract is affected
Diagnosing Crohn's Disease: Colonoscopy or Sigmoidoscopy
Colonoscopy and sigmoidoscopy allow the doctor to directly view the large intestine, which is the lower part of the digestive tract. These techniques can often provide the most accurate information about the intestines. They may be better at detecting small ulcers or inflammation than other techniques. They can be used to assess the severity of any inflammation. Colonoscopy is the most important tool in diagnosing Crohn's disease.
During these procedures, a flexible viewing tube is placed through the anus into the large intestine. An image of the inside of the intestine is often projected onto a video monitor. A sigmoidoscopy involves examining the lowest part of the large intestine. A colonoscopy can provide a view of all of the large intestine. In either case, the doctor can directly view the colon to check for signs of ulcers, inflammation, or bleeding. The doctor can also take small samples of tissue to examine under a microscope. This helps determine whether the tissue shows signs of Crohn's disease or other problems.Diagnosing Crohn's Disease: Video Capsule Endoscopy
For video capsule endoscopy, you swallow a small capsule or pill that holds a miniature video camera. As it travels through the small intestine, it sends images of the lining to a receiver you wear on a belt around your waist. The images are downloaded and reviewed at a computer. The images can provide detailed information about early, mild problems associated with Crohn's disease. This technique may be especially helpful if you have symptoms of Crohn's disease but barium X-rays do not show evidence of the condition.
While video endoscopy can provide valuable information, there are times when it may be best to avoid it:
- If you have an obstruction in the small intestine, the capsule could get stuck and make the obstruction worse.
- If you have a narrowing in the small intestine, such as from Crohn's disease, previous surgery, or previous radiation therapy, the capsule might become stuck.
- Some doctors worry that wireless transmissions from the capsule might interfere with implanted cardiac pacemakers or defibrillators.
Video capsule endoscopy is still under development. Its role in helping to diagnose Crohn's disease is not yet clear.Making a Diagnosis of Crohn's Disease
After the exams, lab tests, and imaging tests are done, your doctor will discuss the findings with you. If your doctor believes you have Crohn's disease, then you can work together to develop a treatment plan to manage the symptoms and control the disease.
Crohn's disease -- also known as ileitis or enteritis -- is a chronic illness. In Crohn's, the intestine, or bowel, becomes inflamed and ulcerated -- marked with sores. Along with ulcerative colitis, Crohn's disease is part of a group of diseases known as inflammatory bowel disease (IBD).
Crohn's disease usually affects the lower part of the small intestine, which is called the ileum. The disease, though, can occur in any part of the gastrointestinal system. Thus, the disorder may affect the large or small intestine, the stomach, the esophagus, or even the mouth. Crohn's can occur at any age. It is most commonly diagnosed in people who are between the ages of 20 and 30.What are the symptoms of Crohn's disease?
The symptoms of Crohn's disease depend on where in the bowel the disease occurs. They also depend on its severity. Symptoms can include:
- abdominal pain and tenderness (often on the lower right side of the abdomen)
- chronic diarrhea
- delayed development and stunted growth (in children)
- feeling of a mass or fullness in the lower right abdomen
- rectal bleeding
- weight loss
Other symptoms can develop, depending on complications related to the disease. For example, a person with a fistula, which is an abnormal passageway, in the rectal area may have pain and discharge around the rectum. Other complications from Crohn's disease include:
- inflammation of the eyes and mouth
- kidney stones
- liver disease
- skin rashes or ulcers
The cause of Crohn's disease is not known. It is likely that there is a genetic component. About 20% of people with Crohn's disease have a blood relative with a form of IBD. People of Jewish heritage have a greater risk of developing Crohn's.
Crohn's disease may involve the immune system. The immune system of a person with Crohn's may treat bacteria, food, and other substances as foreign invaders. That leads to chronic inflammation from the accumulation of white blood cells in the lining of the intestines. The inflammation then causes ulcerations and injury to the tissues.How is Crohn's disease diagnosed?
A number of tests are used to distinguish Crohn's disease from other gastrointestinal conditions. First, your physician will review your medical history. This information is helpful because Crohn's disease is more common in people who have a first-degree relative -- mother, father, sister, or brother -- with IBD. After a physical examination is done, the doctor may order the following tests:
Crohn’s Disease Treatment: Common Medications for Treating Crohn’s(continued)
- Endoscopy (such as colonoscopy or sigmoidoscopy): During this procedure, a flexible, lighted tube called an endoscope is inserted into the rectum and used to view the inside of the rectum and colon. A colonoscopy shows a greater portion of the colon than a sigmoidoscopy does. A small sample of tissue may be taken for testing -- biopsy.
- Blood tests: When testing the blood, the doctor will look for signs of anemia or a high white blood cell count. That would indicate inflammation or infection somewhere in the body.
- Barium X-ray (barium enema or small bowel series): X-rays are often taken of either the upper or lower intestine. Barium coats the lining of the small intestine and colon and shows up white on an X-ray. This characteristic enables doctors to view any abnormalities.
There is no cure for Crohn's disease. The goals for treatment are:
- to reduce inflammation
- to relieve symptoms of pain, diarrhea, and bleeding
- to eliminate nutritional deficiencies
Treatment might involve drugs, nutritional supplements, surgery, or a combination of these therapies. Treatment choices depend upon where the disease is located and how severe it is. They also depend on the complications associated with the disease and the way the person has responded in the past to treatment when symptoms reoccurred.What kinds of drugs are used to treat Crohn's disease?
There are several types of drugs used to treat Crohn's disease. The first step usually involves reducing inflammation. Many people are first treated withsulfasalazine (Azulfidine). This drug is the most common of those that contain mesalamine. Mesalamine is also known as 5-aminosalicylic acid, or 5-ASA. Possible side effects of sulfasalazine and other mesalamine-containing drugs may include:
If a person does not respond to sulfasalazine, the doctor may prescribe other types of drugs that contain 5-ASA. These other products include: