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What are the types of Crohn's disease?

The symptoms and signs of Crohn's disease are a function of the location and pattern of disease.

Disease Location

1. Gastroduodenal Crohn's Disease

  • Also known as upper GI Crohn's disease
  • Uncommon - symptoms in approximately 5% of patients
  • Affects the stomach and first part of the small intestine (duodenum)
  • Symptoms include nausea, loss of appetite, weight loss, vomiting, and pain in the upper abdomen

2. Jejunoileitis

  • Inflammation of the second part of the small intestine (jejunum)
  • Uncommon
  • Symptoms include diarrhea, abdominal pain (usually after eating), malnutrition due to malabsorption of nutrients, and weight loss

3. Ileitis

  • Inflammation of the last part of the small intestine (ileum)
  • Occurs in approximately 30% of patients
  • Symptoms include diarrhea, abdominal pain (often in the right lower quadrant), and weight loss

4. Ileocolitis

  • Inflammation of the ileum and colon (most often the right side of the colon)
  • Most common type of disease, affecting approximately 50% of patients
  • Symptoms similar to Crohn's ileitis: diarrhea, abdominal pain (often in the right lower quadrant), and weight loss

5. Crohn's Colitis

  • Inflammation of the colon only
  • Not uncommon. Approximately 20% of patients with Crohn's
  • Symptoms include diarrhea, rectal bleeding, and abdominal pain
  • Perianal disease and the extraintestinal manifestations of Crohn's disease are more common in patients with involvement of the colon. Unlike in ulcerative colitis, where the inflammation is continuous and almost always starts in the rectum, working its way back into the colon, Crohn's disease often spares the rectum. In addition, Crohn's disease is often not continuous; there can be a healthy segment of bowel between diseased segments. This type of involvement is typical of Crohn's disease and is referred to as a "skip lesion."

6. Perianal Disease

  • Affects up to 1/3 of patients with Crohn's disease
  • Patients can present with fistulae, fissures, skin tags, or abscesses:
    • Perianal Fistulas: perianal fistulas result from small collections of inflammation and infection that tunnel their way from the anal muscle (sphincter) to the skin around the anus. This leads to drainage of mucus, stool, or pus from openings around the perianal area. If the external opening closes, an abscess may develop, which characteristically will present with swelling and pain in the perianal area, and associated fever. Typically, this requires treatment with antibiotics and, often, surgical drainage.
    •  Fissures: fissures are sores or ulcerations in the lining of the skin that crosses the anal canal; often, these can be quite painful.
    • Skin tags: patients with Crohn's can develop fleshy growths just outside the anus which are known as skin tags. Occasionally, these can be confused with hemorrhoids. They are usually not painful or clinically relevant.
Distribution of Crohn's Disease in the intestinal tract 

Disease Pattern

1. Inflammatory

A form of Crohn's disease that is due to inflammation of the intestine. Symptoms include diarrhea, abdominal pain, weight loss, fever, bleeding, fatigue, loss of appetite, and delayed growth in children. Patients can also develop small bowel obstructions or a mass in their right lower quadrant. These patients respond best to medical therapy. This pattern is typical early in the course of Crohn's disease.

2. Fibrostenotic

Barium study showing (arrows) narrowing in the small bowel from Crohn's disease

A form of Crohn's disease that is usually seen in patients with Ileal disease. Over time, persistent inflammation can lead to scarring within the intestinal wall. Continued build-up of scar tissue within the intestinal wall causes narrowing of the intestine itself. Eventually the intestine becomes so narrow that even a small amount of inflammation causes closure of the lumen, resulting in a small bowel obstruction. These small bowel obstructions are characterized by severe abdominal pain, nausea, vomiting, and lack of passing bowel movements (constipation) or gas from below. Patients with known stricturing disease will likely be asked to follow a low-residue diet. Most small bowel obstructions resolve quickly with conservative therapy (nothing to eat, intravenous fluids). Eventually, patients with fibrostenotic disease are likely to require surgery to remove the scarred section of bowel to prevent recurrent small bowel obstructions in the future.

3. Perforating/Fistulizing

Because Crohn's disease can affect all layers of the bowel wall (transmural), patients can develop a perforation (hole) of the intestine, leading to leakage of bowel contents into the abdominal cavity, or they can develop a fistula, which is an abnormal connection or tunnel from one loop of bowel to another or even to another organ.

  • Perforation - Can present acutely with severe abdominal pain, rigid abdomen ("surgical abdomen"), fever, and chills. The symptoms can be similar to those of appendicitis. Alternatively, it can present more indolently (slowly) with a mass in the abdomen, fever, chills, and less severe pain. A perforation usually results in an intraabdominal abscess (collection of bacteria and inflammatory cells) that requires antibiotics and drainage, either surgically or via a radiologically-placed drain.
  • Fistula - The symptoms of a fistula depend on the organ to which the fistula connects: Examples of different types of fistula include bladder (entero-vesical), vagina (entero-vaginal), skin (entero-cutaneous), and intestine (entero-enteric). The most common type of fistula is actually a perianal fistula, but this entity will be considered separately below.
    • Entero-vesical fistulae often lead to recurrent urinary tract infections. Patients may also complain of passing gas, blood, or stool when they urinate.
    • Entero-vaginal fistulae may present with passage of gas or stool through the vagina.
    • Entero-cutaneous fistulae cause drainage of the bowel contents through the skin's surface.
    • Entero-enteric fistulae can be asymptomatic or may present with diarrhea or an abdominal mass.

Contact Information

Inflammatory Bowel Disease Program
Digestive Disease Center
Beth Israel Deaconess Medical Center
330 Brookline Avenue
Boston, MA 02215