Crohn’s disease is an idiopathic, chronic, inflammatory process that can affect any part of the gastrointestinal (GI) tract from the mouth to the anus. Individuals with Crohn’s disease often experience periods of symptom relapse and remission. Appropriate medical and surgical therapy help patients to have a reasonable quality of life, with an overall good prognosis and a very low risk for a fatal outcome.
Genetics - Studies have found compelling evidence of an inheritable risk for the development of Crohn’s disease. However, classic Mendelian inheritance is not seen.
Risk – Smoking doubles the risk of developing Crohn’s whereas the risk of developing ulcerative colitis is lower in people who smoke than in those who have never smoked or in those who stopped smoking before their diagnosis.
Location - Although any area of the GI system may be affected in patients with Crohn disease, the most common site of the chronic inflammatory process is the ileocecal region, followed by the small intestine alone (about 30%), the colon (about 20%), the stomach (rarely), and the mouth. The esophagus is rarely involved.
Symptoms - Colonic Crohn’s is typically associated with symptoms of bloody mucopurulent diarrhea, cramping abdominal pain, and urgency to defecate. Low-grade fever, prolonged diarrhea with abdominal pain, weight loss, and generalized fatigability are usually reported.
Diagnosis - Colonoscopy is usually required for the diagnosis and treatment of patients with suspected or established inflammatory bowel disease. The procedure is useful for tissue sampling and differential diagnosis, evaluation of mass lesions, and cancer surveillance. Crohn’s disease is initially diagnosed on the basis of a combination of clinical, laboratory, biopsy, and radiologic findings.
Treatment – Therapy for individuals with mild Crohn’s disease is typically administered in a sequential "step-up" approach, in which less aggressive and less toxic medical treatments are tried first, and followed by more potent medications when appropriate.
For the treatment of moderate to severe Crohn disease a "top-down" approach is used; doctors may start treatment with a biologic agent, steroids or an immunotherapy drug as needed. There are several newer medicines that have been developed and the majority of individuals can have their disease controlled. If however medical therapy for active Crohn’s disease fails, surgical resection of the inflamed bowel with restoration of continuity is indicated.
Crohn’s disease can, in some cases, lead to colon cancer; your risk depends on how long you've had it and whether your colon is affected. People with Crohn’s disease that affects the colon should get screened early and often for colon cancer. Screening guidelines recommend patients undergo a colonoscopy a few years after being diagnosed and continue to have colonoscopies every 1 to 2 years thereafter.