Crohn’s disease (more appropriately designated as Crohn disease) is an inflammatory disease of the intestine which may effect any part of the GI tract. It is one of the 2 types of distinct inflammatory bowel disease (IBD).
Background: Crohn’s disease is a chronic disease of the intestine. The intestine becomes inflamed which leads to pain, loose stools, and bleeding. Over time, complications such as scar tissue (stricture) or rupture (intestinal perforation) may develop. Unlike it’s counterpart, ulcerative colitis (which is limited to the colon), Crohn’s disease may affect any part of the GI tract. The terminal ileum (junction of the large and small intestine) is most commonly affected, while the rectum is often spared. Crohn’s disease may have a wide variety of different ways of showing up. This can make the initial diagnosis more difficult in some people.
Prevalence in the United States is about 7 cases per 100,000 people. While it is more common in Caucasians and Ashkenazi (Eastern European) Jews, anyone may have it. Doctors sometimes refer to the ages at which Crohn’s disease develops as “bimodal.” It is common to first develop either during the teen’s-20’s or around the ages of 50’s-70’s. Males and females are at equal risk. Crohn’s disease, however, is 3x more likely in smokers, and people with a first degree relative with Crohn’s are at a 4-20x increased risk.
Presenting problem: The most common initial symptoms are crampy abdominal pain, chronic diarrhea, low-grade fever, weight loss, and/or fatigue. Diarrhea is usually non-bloody and intermittent. Abdominal pain may be in the right lower part of the abdomen, around the belly button (umbilicus). The pain is often relieved by defecation. If there is colon involvement, pain can be diffuse and blood may be present in the stool (bloody stools). Some patients do not present to a physician until they have a bowel obstruction (intestinal blockage). Other symptoms include intestinal spasm, loud intestinal noises, cramping, bloating after meals. Associated problems may include chronic constipation or even complete inability to have a bowel movement (obstipation). Children may present with growth failure or delayed puberty due to malabsorption
- The exact cause remains unknown
- Genetics, environmental, vascular, immunologic, and dietary causes have all been suggested in development of Crohn’s disease
- Researchers believe several genes may contribute to Crohn’s disease
- Specifically, mutations in the CARD15/NOD2 gene have shown increased susceptibility
- TNF-a and interleukins have also been implicated in disease development
- Crohn’s results in a T-helper Type 1 immune response â†’ increased IL-12, TNF-a, and IFN-g
- In particular, TNF-a has been shown to have a critical role in the high degree of inflammation in Crohn’s
- Crohn’s patients demonstrate increased TNF levels in stool, mucosa, and blood
- Environmental factors may contribute: industrialized country, smoking
- Diet factors
Pathophysiology (how the disease gets worse)
- Lesions start as focal inflammation around crypts and result in superficial mucosa ulceration
- With progression, inflammation spreads to deep layers and begins noncaseating granuloma and lymphoid aggregate formation
- Superficial ulcers will become deep serpiginous
- Linear ulcers and transverse fissures will create a cobblestone appearance
- Healthy tissue separates areas of disease (skip lesions)
- Transmural inflammation results in narrowing of the bowel lumen and thickening of the wall
Extra-intestinal Manifestations (Crohn’s problems other than intestine)
- Aphthous ulcers (mouth sores)
- Uveitis (eye inflammation)
- Episcleritis (eye inflammation)
- Seronegative spondyloarthropathy (joint pain)
- Ankylosing spondylitis, sacroiliitis (joint and back pain)
- Erythema nodosum (skin lumps)
- Pyoderma gangrenosum (skin problem)
- Variable liver involvement: elevated liver enzymes, benign pericholangitis, sclerosing cholangitis, autoimmune hepatitis
- Clubbing of the fingers
- Amyloid deposits in kidney
- Anemia (low red blood cell counts)
- Leukocytosis (elevated white blood cell counts)
- Acute inflammatory markers (sed rates, CRP, etc.)
- Signs of malabsorption (low albumin, other labs)
- Serology (p-ANCA which is suggestive of UC), Prometheus IBD Serology 7
- Stool samples (to exclude infection, to check for white cells, to look for blood)
- Colonoscopy with biopsy
- Upper GI with small bowel follow-through
- Barium enema
- CT scanning for stricture, fistula, obstruction, appendicitis
- Capsule endoscopy
- MR Enterography
- Treatment of children should always be done by a board certified pediatric gastroenterologist.
- No cure for Crohn’s disease
- Goal of treatment is to treat flare ups and maintain remission
- Treatment options: medications, lifestyle changes, surgery
- Acute treatment
- Antibiotics (metronidazole, ciprofloxacin) to treat infection
- Aminosalicylate (Mesalazine, Sulfasalazine) and corticosteroids (prednisone) to reduce inflammation
- Immunosuppressive Agents: azathioprine, 6-mercaptopurine
- Anti-TNF-a antibody: infliximab, adalimumab (Remicade, Humira)
- Surgery reserved for patients with persistent symptoms despite high-dose steroids, complications, dysplasia (precancer), fistula, abscess, severe bleeding or obstruction
- Crohn’s disease cannot be cured by surgery.Â Surgery treats the complications of the disease.
- Higher need for more surgery in patients who need surgery a first time.
- Scar formation often contributes to stricture development
- Studies have suggested, following an initial resection another procedure may be necessary in 5 years
- Lower recurrence seen with total colectomy and ileostomy verses segmental procedures
- Resection and anastomosis
- Often requires ostomy to allow bowel to heal
- Risk of fistula or stricture development
- Strictureplasty: 1/2 of patients will require re-operation, most effective in jejunum and ileum. Preferable for patients with prior resection who are at risk for short bowel syndrome
- Balloon dilation. Long term success has not been determined. Appears to be useful in delaying resection or strictureplasty. Risk of bowel tearing.
- In children, surgical resection (rather than stricturoplasy) of ileocolic stricture often results in marked reduction in symptoms if the disease is limited to one area. Again, surgery does not cure the disease.
Potential Complications from Crohn’s Disease: (bolded entries often require surgery)
- Obstruction (intestinal blockage)
- Fistula (a track between the intestine and any other structure (skin, bladder, intestine, vagina, etc))
- Malabsorption (inability to absorb nutrients)
- Perianal disease (inflammation of the area around the anus)
- Toxic megacolon (a massively stretched colon)
- Perforation (rupture of the intestine)
- Severe GI bleeding (blood in the stool which causes anemia).
- Beattie, R.M.; N. M. Croft, J. M. Fell, N. A. Afzal and R. B. Heuschkel. “Inflammatory bowel disease”. Archives of Disease in Childhood 91 (5): 426-32. May 2006.
- Bernstein, Charles N. “The Epidemiology of Inflammatory Bowel Disease in Canada: A Population-Based Study”. The American Journal of Gastroenterology 101 (7): 1559-1568. July 2006.
- Hanauer, Stephen B. “Inflammatory bowel disease”. New England Journal of Medicine 334 (13): 841-848. March 1996.
- Heppel, J. â€œSurgical Treatment of Crohnâ€™s Diseaseâ€. UpToDate. March 2007.
- Loftus, E. V.; P. Schoenfeld, W. J. Sandborn. “The epidemiology and natural history of Crohn’s disease in population-based patient cohorts from North America: a systematic review”. Alimentary Pharmacology & Therapeutics 16 (1): 51-60. January 2002.
For an illustrated view of the body’s digestive system, click here.
Crohn’s disease of the terminal ileum. The bowel towards the left is fairly normal appearing. Notice how the fat extends almost completely around the Crohn’s bowel. This is termed “creeping fat.” The cecum is the large bulbous bowel at the top.
This cross-sectional view shows white “contrast agent” which the patient drank a few hours prior to the scan. The walls of the intestine would normally be very thin (perhaps 2% the thickness of the entire width). In this image, the wall thickness (on each side of the white contrast agent) is 33% the width of the bowel loop.
Crohn’s stricture. This picture shows how the bowel upstream from a stricture becomes enlarged or “dilated.”
This photo shows the severe inflammation present on the inside of the bowel. The wall of the bowel is thick and very rigid. Recent bleeding can be seen on the inner surface of the intestine.
This ostomy formed a communication with the skin away from the surgical site. Removal of the bowel was required to control the associated chronic fistula.
Crohn’s stricture. Another example of the thickening of the wall that results in intestinal blockage, pain, and bleeding.