Crohn’s disease of the esophagus is rare (< 5%)

Symptoms include difficulty or pain with swallowing

A fungal infection called “thrush” can develop in the esophagus especially after antibiotics or corticosteroid use

Symptoms of thrush may include painful or difficult swallowing or whitish plaques inside the mouth, tongue, or back of the throat

After food is swallowed, it passes through the esophagus into the stomach

The stomach’s main function is digestion (break down food through muscular contractions and by acid and digestive enzymes secretion)

Stomach involvement is rare (< 5%) in Crohn’s disease but can present with similar symptoms as gastritis

Gastritis (inflammation of the stomach) can occur for several reasons including medication effect (i.e. steroids, ibuprofen, oral iron) and/or infections (i.e. Helicobacter pylori)

The first part of the small bowel is called the duodenum. It receives digested food particles from the stomach and releases compounds to neutralize stomach acid. It also receives secretions from the pancreas and bile ducts to help break down starches, fats, and proteins.

The jejunum’s major role is absorption of nutrients

The proximal small bowel may have involvement of Crohn’s disease resulting in:

Inflammation causing pain and poor absorption of vitamins and micronutrients

Strictures (narrowing of the bowel) causing pain, bowel obstruction, nausea, vomiting

Fistula formation (abnormal connections between two organs) into other portions of the small bowel or colon (may not have symptoms from this)

A function of the ileum is to absorb vitamin B12. Some patients may need supplementation with vitamin B12 after surgery if part of their ileum is removed

The ileum also resorbs bile acids, which are involved in fat absorption and elimination

Patients may experience diarrhea due to excess bile acids entering the colon after surgery to remove the ileum

This area is not involved in ulcerative colitis, but is commonly affected in Crohn’s disease

Imaging studies, including CT, MRI or small bowel series provide a way to evaluate the majority of the small bowel when looking for areas of inflammation, narrowing or fistulas

Video capsule endoscopy is a small camera that is swallowed and takes pictures of the small bowel to evaluate small bowel Crohn’s disease

The terminal ileum (“TI”) can be seen during colonoscopy

The terminal ileum is located in the right lower quadrant of the abdomen

It is the end of the small bowel and connects to the beginning of the colon (cecum)

It is frequently affected in Crohn’s disease patients (~40%)

This area can develop strictures (narrowing) due to chronic inflammation and fibrosis (scarring of the intestine)

The terminal ileum is the most frequent area that requires resection (surgical removal) in Crohn’s patients

Mild redness / irritation in the terminal ileum may occur in patients with pancolitis (inflammation affecting the entire colon) and is known as “backwash ileitis”

Backwash ileitis is distinct from the ileal inflammation that can be seen in Crohn’s disease. It does not change a patient’s diagnosis from ulcerative colitis to Crohn’s disease

This valve separates the colon from the small bowel

It is a marker of the beginning of the colon and is frequently photographed during a colonoscopy to indicate the entire colon was visualized

Frequently involved in Crohn’s disease

Frequently removed during Crohn’s disease surgeries due to narrowing or fistula/abscess formation

The valve can become “fibrotic” (scarred) and “strictured” (narrowed) with longstanding or aggressive disease

This may lead to small bowel bacterial overgrowth since it obstructs the separation between small intestines and colon – symptoms may include bloating, cramping, nausea and diarrhea

Occasionally, these narrowings may be treated during colonoscopy with a procedure called a “dilation” which stretches open the narrowing to make it wider

The ileocecal valve is rarely to never scarred or narrowed among patients with ulcerative colitis

Some patients with ulcerative colitis have wide, gaping ileocecal valves

Located in the cecum (the first part of the colon)

The exact function is not known and surgical removal has no observable health problems

In left-sided ulcerative colitis or proctitis there may be inflammation surrounding the internal opening of the appendix known as a “cecal red patch”

Some epidemiologic studies have suggested that appendectomy is associated with a lower risk of developing ulcerative colitis

There is no clear association between appendectomy and Crohn’s disease

The cecum is the beginning of the colon and is connected to the small bowel (terminal ileum)

Within the cecum is the ileocecal valve and the appendiceal orifice (opening)

The cecum along with the terminal ileum are the most frequent parts of the GI tract that are affected by Crohn’s disease

In extensive colitis or pancolitis the inflammation extends from the rectum to the cecum (entire colon)

Occasionally, there can be an area of redness in the cecum, particularly near the appendiceal orifice, among patients with left-sided colitis or proctitis called the “cecal red patch”

This area of the colon is located on the right side of the abdomen between the cecum and the transverse/distal colon

It may or may not be involved in patients with Crohn’s disease due to the patchy nature of Crohn’s disease

Ulcerative colitis that is pancolitis or extensive colitis will have continuous inflammation from the rectum through the ascending and proximal colon

Left-sided ulcerative colitis will not involve this area

This organ’s main job is to absorb water

The descending colon is located on the left side of the abdomen

May be affected by Crohn’s disease in the form of inflammation, fistulas (abnormal connections between two organs) or strictures (narrowing of the caliber of the intestines due to acute or chronic inflammation)

Often involved in ulcerative colitis known as “left-sided colitis”

The bottom part of colon; connected to the anus

This is usually an area of relative disease sparing in Crohn’s disease; only 10% of Crohn’s disease patients have rectal involvement

Rectal inflammation in Crohn’s disease can lead to the development of fistulas (abnormal connections between the rectum, skin or adjacent organs)

Universally involved in ulcerative colitis

Inflammation here may cause symptoms of rectal pain, urgency and tenesmus (sense of needing to go to the bathroom but nothing is evacuated or “incomplete evacuation”)

The external opening at the end of the digestive tract where waste is eliminated

Fissures, which are tears in the lining of the anal canal, can be seen in Crohn’s disease. Symptoms include anal pain, spasms, and bleeding

Perianal fistulas (abnormal connection) between the anal canal and skin may occur in Crohn’s disease patients. The initial presentation of fistulizing disease may be an abscess.

Abscesses (infected cavity filled with pus) may form between the anal canal and skin in Crohn’s patients with perianal disease. Treatment requires drainage of the abscess cavity.

Anal skin tags may be seen in Crohn’s patients and may be the result of a chronic anal fissures. Surgery to remove skin tags is not recommended.

Cancers may develop within perianal fistulas

Hemorrhoids are normal blood vessels located at the bottom of the lower rectum

The vessels are typically not sensitive to touch, pain or temperature

Internal hemorrhoids become symptomatic when the connective tissue that anchors them deteriorates. This occurs most commonly with age, but can be seen with pregnancy, straining and prolonged sitting

Treatment is symptom-based and rarely involves surgery

In IBD patients there is an increased risk of poor wound healing

Hemorrhoids are normal blood vessels located at the bottom of the lower rectum

External hemorrhoids are covered by skin tissue and become symptomatic when there is breakdown of the surrounding connective tissue – symptoms include sensitivity to touch, temperature and pain with sitting or during bowel movements

Treatment is symptom-based and rarely involves surgery

In IBD patients there is an increased risk of poor wound healing

Muscle at the end of the anal canal that prevents the escape of feces at baseline, but relaxes to allow stool to pass during defecation

It works actively to keep the anus closed

Can be damaged by anal surgery or childbirth

Fistulas (abnormal connections between two organs) can course through this area and are classified based upon their location relative to the sphincter muscle

Muscle at the end of the anal canal which keeps the canal and opening closed to prevent the escape of feces

Retracts to allow the passage of feces during defecation

Can be damaged by anal surgery and childbirth

Fistulas (abnormal connections between two organs) can course through this area and are classified based upon the location relative to the sphincter muscle

Small sacs that line the wall of the anal canal and drain to anal crypts ending in the space between the internal and external sphincters

They secrete material into the anal canal via the anal duct

The internal component of the anal gland

Blockage of anal crypts may lead to abscess and fistula formation as material resides in the intersphincteric space where the gland ends

The anal canal includes the end of the rectum above the anus

The dentate line divides the upper portion of the anal canal from the lower portion

Blood and nerve supply is different above and below this line, making this an important landmark