Crohn's disease is a form of inflammatory bowel disease (IBD).  It is characterized by varying degrees of active and chronic inflammation of the gastrointestinal tract. The usual symptoms include diarrhea, rectal bleeding, and abdominal pain. Nobody knows exactly what causes Crohn's disease however, activation of the immune system, exposure to bacteria in the gut and genetic factors seem to be involved.  Crohn's disease is treated with medicines such as corticosteroids, other anti-inflammatory agents, and immunomodulators.  It has been seen in children less than 2 years of age rarely, however it is much more commonly diagnosed in teenagers and adults. 

What is Crohn's disease?

Crohn's disease is a disease with an unknown cause that leads to inflammation (ulcers, redness, swelling, pain) in the gastrointestinal tract.  Inflammation can occur anywhere from the mouth to the anus.  When the inflammation is severe, erosion of the intestines can lead to tunnels (a.k.a. - fistulas) from the gut to the outside of the skin, or into the bladder and vagina.  Sores in the mouth or around the anus are common.  The inflammation causes abdominal pain, poor growth, delayed puberty, and sometimes skin rashes, eye problems, and joint pains.

What causes Crohn's disease?

Nobody really knows.  It seems to be caused by an overreaction of the immune system to normal bacteria found in the colon.

What are the symptoms of Crohn's disease?

For some children, the symptoms can be subtle and the diagnosis is not made for years.  Diarrhea, one of the most common complaints, may not be present.  Joint pain may be confused with other disorders such as juvenile rheumatoid arthritis (JRA) or injury.  Often, poor weight gain, decreased energy level or delay in puberty can be the first sign.

• Abdominal pain
• Diarrhea (frequently with blood and mucus)
• Sores in the mouth
• Sores around the anus (large painful bumps or holes with pus/stool drainage)
• Poor weight gain
• Decreased energy level
• Skin rashes or sores
• Delayed puberty
• Joint pains
• Eye problems (redness, pain)

Red Flags (seek medical care immediately)

Really, any of the above symptoms should be evaluated by a physician as soon as possible.

How is Crohn's disease diagnosed?

There is no single test for Crohn's disease.  Often the diagnosis is not made until symptoms have persisted for months or years.  The combination of the patient's history, blood tests, stool studies, imaging studies and endoscopy can confirm the diagnosis.

• Blood tests - Anemia (or low red blood cell count) is common in Crohn's disease.  This is due to loss of blood in the gut and poor production of red cells due to the overall illness.  Markers of inflammation (such as ESR and CRP) can be helpful also.
• Stool studies - Several infections can cause bloody diarrhea that may be confused with Crohn's disease.  These include salmonella, shigella, campylobacter, clostridium difficile, giardia, entamoeba histolytica.  Tests should be done to rule out these infections.

Imaging studies -

• CT scans are fairly good for seeing bowel wall thickening due to inflammation and collections of fluid or pus in the abdomen.  This amount of radiation should be avoided in children if possible. 
• MRI is also a decent study for looking at the intestines and colon.  MRI takes about 45 minutes or longer, so little children may have difficulty staying still for this long.  Sedation is sometimes used. 
• X-ray studies with swallowed contrast are fairly good for evaluating the small intestines for narrowing or large ulcers due to inflammation.
• Endoscopy, including upper gastrointestinal endoscopy and colonoscopy are the best test for confirming the diagnosis.  Inflammation can be seen with the endoscope camera.  Biopsy samples can be taken for a Pathologist to review under a microscope.  These procedures require sedation or anesthesia and are usually done by a Pediatric Gastroenterologist.
• Capsule endoscopy is a large pill-like camera that is swallowed.  It has a pulsating light and camera that sends pictures to a device worn on the belt.  Usually only kids over 8 years old can swallow this pill, but in younger children, the pill can be placed in the stomach during upper gastrointestinal endoscopy.  Once the camera has traveled through the gut and has taken thousands of pictures, it is pooped out and discarded.  The pictures are downloaded and reviewed by a Gastroenterologist.

How is Crohn's disease treated?

5-ASA derivatives -

Medicines like mesalamine (Asacol, Pentasa, Lialda) and sulfasalazine (Azulfadine) are anti-inflammatory medicines similar to aspirin.  They are relatively benign medicines but are frequently not powerful enough to be the only treatment.

Immunomodulators and immunosuppressants-

• Mercaptopurine (6-MP) or azathioprine (Imuran) are chemotherapy agents that are used in relatively low doses to "cool down" the immune system.  These medicines are the standard therapy for Crohn's disease.  Blood counts and liver function tests must be watched closely for unwanted side effects.
• Glucocorticoids ("steroids") like prednisone and prednisolone are effective treatments for Crohn's disease and have a rapid onset.  They are commonly used at the beginning of the disease until 6-MP or Imuran can take effect.  They are also commonly used for Crohn's "flares."
• Antibodies to TNF-alpha - medicines like Remicade and Humira contain antibodies to one of the major inflammatory proteins in Crohn's disease, TNF-alpha.  These antibodies "block" the effects of TNF-alpha.  Remicade is given as an intravenous infusion every few weeks and Humira is given as a shot.

Antibiotics -

Antibiotics are sometimes useful, especially if there is a bacterial infection of the intestines complicating Crohn's disease.  Medicines like metronidazole (Flagyl) and ciprofloxacin (in older children) are used.

Rectal suppositories and enemas -

The 5-ASA deriviatives and glucocortocoids are available as enemas and suppositories.  They may be helpful for disease in the rectum and last part of the colon.

What are the complications of Crohn's disease?

Flares of Crohn's disease can be severe and require hospitalization.

Fistulas - tunnels can form from the intestines to the bladder, skin or vagina.

Abscesses - Fluid and pus can collect in the abdomen or near the skin.  These may have to be drained with surgery.

Intestinal blockage - Scar tissue in the intestines can cause a blockage that may require surgery.

Anemia - Blood loss and poor blood production may require a blood transfusion.

Infections - Use of immunomodulators increases the risk of developing infections anywhere in the body.

Severe disease - Sometimes surgery is required to remove a section of intestines with severe disease.  Unfortunately this does not cure the disease.

Cancer - Children on immunomodulators are probably at increased risk for developing cancer.  This risk is low and may be less than the risk of developing cancer from poorly-treated Crohn's disease.

What happens with Crohn's disease long-term?

Well-treated Crohn's disease should not limit a normal lifestyle and lifespan.