Inflammatory Bowel Disease

What is Inflammatory Bowel Disease?

Inflammatory bowel disease is a medical condition characterized by autoimmune injury and inflammation of the gastrointestinal tract.  This disorder is generally categorized into 2 main subtypes: Crohn’s disease and Ulcerative Colitis.  These two conditions have significant overlap but also have unique features amongst them.  Crohn’s disease may affect any portion of the gastrointestinal tract from the mouth down to the anus.  In contrast, ulcerative colitis typically affects the large bowel (colon).

Patients with these conditions often experience episodic abdominal pain, bloating, nausea/vomiting, diarrhea, bloody stool, and mucous in the stool.  Patients may also develop low grade fever and malaise – potential long term complications include nutritional deficiencies, fistula formation, and colon cancer.

What Causes Inflammatory Bowel Disease?

Inflammatory bowel disease is likely caused by an interplay between genetic and environmental factors.  Crohn’s disease and ulcerative colitis are forms of autoimmune inflammatory disease in which the immune system inappropriately attacks normal body tissue and organs – such as the gastrointestinal tract.

Inflammation in the gastrointestinal tract of patients with Crohn’s disease may cause:

  • Oral ulcers
  • Small intestinal inflammation
  • Inflammation of the large intestine – colitis
  • Proctitis – rectal inflammation
  • Anal fissures

Patients with ulcerative colitis or Crohn’s disease affecting the colon typically have abdominal pain, bloating, and bloody diarrhea due to inflammation, mucosal ulceration, and bleeding in the large intestine.  Long-term or intermittent inflammation involving the terminal ileum – as is frequently seen in Crohn’s disease –may result in the development of fat malabsorption and nutritional deficiencies (especially vitamins A, D, E, and K).  Chronic intestinal inflammation may also result in the formation of fistulae, abscesses, and strictures.

How Common is Inflammatory Bowel Disease?

Inflammatory bowel disease is exceedingly common in the United States and responsible for frequent primary care visits.  The condition often requires referral to a gastroenterology specialist if first-line and conservative measures are unsuccessful.

The annual incidence of ulcerative colitis in North America is approximately 2-19 cases per 100,000 people.  Furthermore, the annual incidence of Crohn disease is bout 3-20 cases per 100,000 people.  Ulcerative colitis affects an estimated 238 per 100,000 Americans and Crohn disease occurs in about 201 per 100,000 Americans.

Signs and Symptoms

Symptoms of inflammatory bowel disease often include:

  • Painful oral ulcers
  • Abdominal pain
  • Bloating
  • Nausea & vomiting
  • Diarrhea
  • Bloody stool
  • Stool with mucous

Patients may also have malaise and low grade fever.  Episodes may be intermittent lasting days to weeks if left untreated.  Severe cases of gastrointestinal inflammation can result in exquisite abdominal pain, vomiting, and the inability to tolerate anything by mouth.  These cases require hospitalization with intravenous fluids, pain management, and corticosteroids.

A subset of patients will develop toxic megacolon with death of intestinal tissue requiring surgical debridement – patients with this type of presentation are generally very ill and have a higher incidence of morbidity and mortality.


The diagnosis of inflammatory bowel disease is suggested based on symptoms and physical examination, but typically confirmed with upper and lower endoscopy studies.  During these procedures, your doctor will visualize the upper gastrointestinal tract by providing you with sedation and advancing a camera down the mouth into the esophagus.

They will continue to advance the scope, evaluating for any ulcers or inflammatory lesions, all the way past the stomach and into the small intestine.  During colonoscopy, a similar procedure is performed but your doctor will enter the rectum and advance a scope through the colon.

Sometimes, you doctor may recommend a radiographic study in which they have you swallow contrast and perform a CT scan or MRI – this test is obtained in order to evaluate the portion of the bowel that cannot be visualized with upper and lower endoscopy.

Other commonly ordered blood tests include a CMP (comprehensive metabolic panel), CBC (complete blood cell count), and coagulation studies (PT/INR, PTT).  Your doctor will usually check your stool for Clostridium difficile toxin prior to performing colonoscopy in order to rule out C. difficile colitis – this is an infectious form of colitis that can mimic or coexist with inflammatory bowel disease.

Inflammatory Bowel Disease Medication and Treatment

Infectious colitis must first be excluded as an etiology of symptoms during acute flares of inflammatory bowel disease – this frequency involves ruling out C. difficile infection.  Patients are then typically treated with short-term oral or intravenous corticosteroids which may include Orapred (prednisone) or Solumedrol (methylprednisolone), respectively.

Patients with mild ulcerative colitis can benefit from oral mesalamine, which is available as Pentasa, Asacol, or Canasa.

Individuals with limited ulcerative proctitis are often prescribed mesalamine rectal suppositories.  Occasionally they will require use of Rowasa (mesalamine enemas).  Cortenema and Colocort (corticosteroid enemas) may also be beneficial in some patients.

In more severe or recurrent cases of inflammatory bowel disease, you doctor may recommend long term treatment with Imuran (azathioprine).  Occasionally, they will prescribe Neoral (cyclosporine) or Entyvio (vedolizumab).


  1. Silverberg MS, Satsangi J, Ahmad T, et al. Toward an integrated clinical, molecular and serological classification of inflammatory bowel disease: report of a Working Party of the 2005 Montreal World Congress of Gastroenterology. Can J Gastroenterol 2005; 19 Suppl A:5A. -
  2. Satsangi J, Silverberg MS, Vermeire S, Colombel JF. The Montreal classification of inflammatory bowel disease: controversies, consensus, and implications. Gut 2006; 55:749. -
  3. Kornbluth A, Sachar DB, Practice Parameters Committee of the American College of Gastroenterology. Ulcerative colitis practice guidelines in adults: American College of Gastroenterology, Practice Parameters Committee. Am J Gastroenterol 2010; 105:501. -
  4. Lichtenstein GR, Hanauer SB, Sandborn WJ, Practice Parameters Committee of American College of Gastroenterology. Management of Crohn’s disease in adults. Am J Gastroenterol 2009; 104:465. -




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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.