After a patient has had a total proctocolectomy (removal by surgery of the colon and rectum), a procedure called an ileal pouch-anal anastomosis (IPAA) is performed. During the construction of an IPAA, the ileum, or lowest part of the small intestine, is connected to the anus to create a structure (pouch) that can store and eliminate stools.
The surgeon creates a J-pouch (which resembles the letter J) to provide for the storage area. Other pouch shapes (S and K) can also possibly be constructed. The pouch helps improve the patient’s quality of life by preserving the natural route of defecation, and reduces the risk of growths that could develop into cancer. However, after this surgery, some patients may get pouchitis.
Pouchitis is an inflammation (swelling) of the pouch that occurs when the pouch becomes irritated and inflamed. The inflammation can cause increased bowel frequency (having to go to the bathroom more often), abdominal cramping or bloating, lower abdominal pain, or sometimes blood in the stool. This condition should be evaluated and managed by an experienced gastroenterologist.
About half of patients who undergo IPAA surgery for ulcerative colitis will have pouchitis at least once in their lifetimes. Up to 40 percent of patients with IPAA develop pouchitis every year.
The cause of pouchitis is not entirely clear, but it almost always occurs in patients with ulcerative colitis or another form of colitis, and sometimes in those with familial adenomatous polyposis (FAP), a genetic (inherited) condition in which many polyps form in the colon.
The changes in the bowel pattern that happen during IPAA surgery may play a role in causing pouchitis. In its normal state, the ileum’s job is to absorb nutrients. After IPAA surgery, the ileum is artificially changed into a storage space for waste matter. The mucous membrane, or inner lining of the ileum, launches an immune response to the different types of bacteria it is exposed to, which leads to inflammation.
There are a number of factors associated with the development of pouchitis, including the following:
In addition, reduced blood flow to the pouch can cause ischemic pouchitis.
Symptoms of pouchitis include the following:
In severe cases, symptoms may also include:
The doctor will consider the patient’s symptoms and the results of an endoscopy (examination of the inside of the pouch with an instrument called an endoscope). A pouchoscopy (endoscopy of the pouch) can show how widespread the inflammation is, whether or not the ileum is irritated, or if the patient has Crohn’s disease or Crohn’s-like disease of the pouch.
Endoscopy can also show if the patient has cuffitis (inflammation at the anal transition zone, or cuff), or abnormalities such as narrowed passages or cavities or openings. Patients who have cuffitis often have bright red blood (mild to moderate, or on wiping) in stool.
The doctor may take a biopsy (sample of the tissue) during the endoscopy to look for other unusual things, such as polyps, infection, any inflamed granulated (grainy) tissue, or a restricted blood supply.
Imaging studies such as contrast pouchography, CT (computed tomography), gastrografin enema, barium defecography, and/or MRI (magnetic resonance imaging) of the pelvis or abdomen may also be used to help with diagnosis. A test called anorectal manometry is helpful in learning if the pelvic floor is not functioning properly, especially in patients who strain during defecation.
Pouchitis is usually treated with a 14-day course of antibiotics. The doctor may also recommend probiotics (“good” bacteria that normally live in the digestive tract) such as Lactobacillus, Bifidobacterium and Thermophilus.
Some patients may develop chronic (long-term) pouchitis. A low-carbohydrate and/or low-fiber and high protein diet may help relieve symptoms of chronic pouchitis, or the patient may require therapy with anti-inflammatory agents or even biological agents. Antidiarrheal agents may be used to treat frequent or loose bowel movements.
Patients who are having a first episode of pouchitis are almost always treated successfully with antibiotics. However, in many cases, the disease relapses (comes back) at a later time.
The prognosis for a patient with pouchitis depends on each patient’s illness:
One potential problem with using antibiotics over a long period of time is that the bacteria may adapt and become resistant to the antibiotics.