Colitis Vs Crohn’s Disease
Ulcerative Colitis and Crohn’s Disease are Inflammatory Bowel Diseases (IBD) that affect many people in the United States. They affect the small bowel and colon and may present with symptoms such as abdominal pain, bloody diarrhea, fatigue, weight loss, and anemia. While both diseases have many similarities, there are major differences between the two that help clinicians to make the proper diagnosis.
The two diseases are similar in that both occur at a rate of approximately 10-14 per 100,000 people. Both diseases affect Caucasians and Ashkenazi Jews more often than Asians or Africans, and both diseases are more prevalent in developed nations rather than developing. The fact that both are prevalent in the developing nations has raised a hypothesis on the pathophysiology of inflammatory bowel diseases. It is hypothesized that lack of parasites in the intestines of people living in developed countries has decreased the fitness of the enteric immune system, causing abnormalities of the bowels like IBD. This theory is further supported by the fact that probiotic therapy and even injection of Trichuria Tricuriasis parasites into the intestines has proved to be helpful in relieving symptoms in patients of both Ulcerative Colitis and Crohn’s Disease.
The fact that there are so many similarities between the two diseases has made it hard for clinicians to recognize which disease is presented before them. But, there are differences that need to be looked out for that can facilitate the establishment of a diagnosis quickly. The main differences between UC and Crohn’s Disease is that Crohn’s Disease often spares the rectum whereas Ulcerative Colitis always involves the rectum.
A biopsy of the affected site can further differentiate between the two diseases. If Crohn’s disease is in suspect, a pathologist viewing the biopsy through a microscope should look for characteristic noncaseating granulomas, while for Ulcerative Colitis; the pathologist looks for crypt abscesses.
Another big difference between Ulcerative Colitis and Crohn’s disease is the fact that Ulcerative Colitis only affects the mucosa and submucosa of the GI tract, whereas Crohn’s has a characteristic inflammation that extends through all three of the GI tract layers, namely mucosa, submucosa, and muscularis propria. The fact that Crohn’s affects the colonic wall transmurally predisposes the patient with the disease to perforation of the colonic wall, which could become devastating.
In addition, Crohn’s Disease creates a type of cobblestone appearance and bowel wall thickening through constant inflammation and regeneration of the colonic wall, whereas UC creates an appearance of pseudopolyps out of indentations made by ulcerations of the GI tract.
Both diseases are associated with various complications: Crohn’s Disease characteristically causes fistulas and strictures, while UC causes toxic megacolon, and worse, colonic carcinoma if the disease is left untreated for many years.
An X-Ray can be used to distinguish between the two diseases: one can look out for a typical “string sign” on a barium swallow that appears when the wall of the mucosa has thickened so much, the barium that passes through has the appearance of a string on an X-Ray. In UC, an X-Ray has a typical “lead pipe” appearance due to the atrophy of haustrae of the colonic walls in UC. Both diseases can cause malnutrition and malabsorption.
One big clue to Ulcerative Colitis is the presence of ulcer lesions in the mouth. Ulcerative Colitis is known to cause ulcers of the mouth called Apthous Ulcers.
The treatment of Crohn’s disease is typically with corticosteroids and/or Infliximab, an antibody against TNF-a. The treatment of UC is with an Aminosalicylic Acid agent Sulfasalazine, Infliximab, or removal of the affected part of the colon if the disease gets bad enough. The patient’s apthous ulcers should go away once treatment is initiated.
Yana G. Yevstegneeva, 3rd-year Medical Student.