Pouchitis

Pouchitis is inflammation that develops inside an ileal pouch, a surgically created internal reservoir made from the small intestine. It’s the most common complication after pouch surgery, affecting between 25% and 45% of people who have this procedure. While most cases respond well to treatment with antibiotics, some people experience ongoing or recurring inflammation that becomes more challenging to manage.

Table of contents

• What is pouchitis?
• Who gets pouch surgery and why?
• How common is pouchitis?
• Symptoms of pouchitis
• What causes pouchitis?
• Risk factors
• Diagnosis
• Classification of pouchitis
• Treatment options
• Outlook and prognosis

What is pouchitis?

Pouchitis is swelling and irritation, called inflammation, in the lining of an ileal pouch^[1]. An ileal pouch is a surgically created internal reservoir that serves as a new way to hold and pass stool from your body after your colon and rectum have been removed^[1].

Surgeons construct an ileal pouch from the end of your small intestine, specifically from the last section called the ileum^[1]. The pouch acts as a reservoir that collects stool before it leaves your body, essentially replacing the function of your colon and rectum^[1].

The most common type of pouch is shaped like the letter J, which is why it’s often called a J-pouch. Other shapes include S-pouches and K-pouches^[6]. A J-pouch or S-pouch connects directly to your anus, while a K-pouch connects to a small opening in your abdomen called a stoma^[1].

Pouchitis causes similar symptoms to colitis or proctitis (inflammation in the colon or rectum), including pain and needing to go to the bathroom urgently and frequently^[1]. Most people experience episodes of acute pouchitis, which is temporary inflammation. Less commonly, some people develop chronic pouchitis that won’t go away or keeps coming back^[1].

Who gets pouch surgery and why?

The surgery to create an ileal pouch, called ileal pouch-anal anastomosis (IPAA), is performed when someone needs to have their entire colon and rectum removed due to disease. This removal surgery is called a total proctocolectomy^[1].

The most common reason for J-pouch surgery is ulcerative colitis, a form of inflammatory bowel disease (IBD)^[6]. This procedure is the standard surgical treatment for most patients with ulcerative colitis who require removal of their colon^[3][7].

Other conditions that may require this surgery include familial adenomatous polyposis (a condition where growths called polyps develop in the colon that may turn cancerous), cancer of the colon or rectum, and occasionally other inflammatory conditions^[5][7].

The surgery typically involves two or three procedures. First, the colon and rectum are removed and the J-shaped pouch is created from the ileum. While the pouch heals, doctors usually create a temporary ileostomy, where waste passes through a stoma into an external bag^[6]. After the pouch has healed, which typically takes a few months, another procedure reverses the ileostomy so waste can pass through the internal pouch and out through the anus^[6].

How common is pouchitis?

Pouchitis is very common after ileal pouch surgery. Between 25% and 45% of people with an ileal pouch will experience pouchitis at some point^[1]. Studies show that up to 40% of people develop it within any given year^[1].

The likelihood of developing pouchitis increases over time. The incidence of a first episode of pouchitis is approximately 15% at 1 year, 33% at 5 years, and 45% at 10 years after surgery^[3]. It’s estimated that approximately half of all patients who undergo pouch surgery for ulcerative colitis will develop at least one episode of pouchitis^[7].

Between 10% and 20% of people have recurring episodes of pouchitis^[1]. Pouchitis happens in nearly half of the people who have the procedure^[2], and up to 81% of patients with an ileal pouch may experience it during their lifetime^[10].

Symptoms of pouchitis

The symptoms of pouchitis can vary from person to person and may change over time^[6]. Common symptoms include:

• Increased frequency of bowel movements and urgency to go^[1][2]
• Diarrhea, often watery^[2][5]
• Lower abdominal pain and cramping^[1][2]
• Having to go to the bathroom during the night^[1]
• Bowel incontinence or leaking stool^[1][2]
• Difficulty or straining when trying to pass stool^[1]
• Feeling like you need to go but can’t^[1]
• Blood in your stool^[1][2]
• Fever or chills^[1]
• Joint pain^[2]

In serious cases, the loss of blood and frequent stools can lead to dehydration, malnutrition, or anemia (low levels of iron in the blood) that may require emergency medical care^[6]. Extreme cramping and pain can also occur with pouchitis^[5].

It’s important to note that these symptoms are not necessarily specific to pouchitis. They may arise from other inflammatory or functional pouch disorders, so proper diagnosis is essential^[5].

What causes pouchitis?

The exact cause of pouchitis is still unknown, but researchers believe it involves several factors^[2][3]. The most widely accepted theory involves changes in the bacteria that live in your digestive system.

When part of your small intestine becomes your “new” large intestine after surgery, it’s exposed to different varieties of gut bacteria. These bacteria compete with the types that previously lived there^[1]. Your immune system may react to this change and produce an inflammatory response^[1][4].

In some people, this change in bacteria may lead to an actual infection. Certain types of bacteria, called pathogenic bacteria, try to take over when given the opportunity. While it’s common to have some of these bacteria in your gut without problems, other bacteria normally keep them in check. Ileal pouch surgery changes this balance, giving pathogenic bacteria a chance to dominate^[1].

The pathophysiology of pouchitis, especially chronic pouchitis, is likely multifactorial. It involves genetic predisposition, changes in the gut microbiota, stool stasis (when waste sits in the pouch too long), disrupted or irregular immune system responses, factors related to the mesentery (tissue that attaches organs to the abdominal wall), technical aspects of the surgery, reduced blood flow to tissues, and oxidative stress^[8].

An episode of pouchitis is a common occurrence shortly after ileal pouch surgery. This is called early-onset pouchitis and is considered a normal side effect of the procedure^[1]. It usually goes away with antibiotics, but may come back repeatedly in some people^[1].

Risk factors

Several factors can increase the risk of developing pouchitis after surgery:

Underlying disease: Pouchitis happens more frequently in people who had underlying inflammatory bowel disease, particularly ulcerative colitis^[2]. Pouchitis almost exclusively occurs in patients with ulcerative colitis or indeterminate colitis^[7]. People with extensive ulcerative colitis before surgery are at higher risk^[6].

Medications: Taking nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen sodium can contribute to the development of pouchitis^[2][6].

Other health conditions: Having chronic liver disease, inflamed or hardened bile ducts in the liver (primary sclerosing cholangitis), rheumatologic disorders, or inflammatory polyps in the pouch may increase risk^[6][10].

Genetics: Genetic factors, including mutations in certain genes such as NOD2/CARD15 and genetic variations in interleukin genes, may play a role^[6][10].

Smoking: Smoking may increase the risk of pouchitis^[6].

Diagnosis

To diagnose pouchitis, a healthcare professional will start by taking your medical history and performing a physical exam^[14]. Since pouchitis symptoms don’t always look the same in different people and may change over time, doctors need to rule out other conditions that may be causing your symptoms^[6].

The most reliable tool for diagnosis is endoscopy (examining the inside of the pouch with a small camera) combined with evaluation of tissue samples obtained during the exam^[5]. This procedure is called pouchoscopy and is the most valuable method for diagnosis, monitoring the disease, assessing treatment response, checking for abnormal tissue changes, and delivering treatment directly to the pouch^[8].

During pouchoscopy, doctors typically see reddened pouch tissue, loss of normal blood vessel patterns, and tissue that bleeds easily when touched. They may take small tissue samples called biopsies to examine under a microscope^[1]. These biopsies show evidence of inflammatory cells or red blood cells in the tissue^[5].

Additional diagnostic tests may include:

• Laboratory tests: Blood tests may check for low levels of iron or vitamin D, both of which are common in people with pouchitis. They may also check liver function or test for viral infections^[6].
• Stool tests: These can look for infections such as Clostridioides difficile (C. diff) or cytomegalovirus (CMV)^[14][4].
• Imaging tests: CT scans or MRI may be recommended to get a picture of the inside of your abdomen or pelvis^[6][14].

Classification of pouchitis

Once pouchitis is diagnosed, doctors classify it based on several factors to guide treatment decisions^[5][3].

By duration: Pouchitis is classified as acute when it lasts less than or equal to four weeks, or chronic when it lasts four weeks or more^[5].

By pattern: The pattern can be infrequent (1-2 acute episodes), relapsing (three or more episodes), or continuous^[5].

By response to treatment: Pouchitis is labeled as treatment-responsive or treatment-refractory (doesn’t respond to treatment), with the specific medication noted^[5].

Chronic antibiotic-dependent pouchitis (CADP): This occurs when acute pouchitis happens more than a few times a year and the person becomes dependent on antibiotics^[1].

Chronic antibiotic-refractory pouchitis: This is when antibiotics start to work less and less effectively^[1]. This condition has been listed as one of the five difficult-to-treat inflammatory bowel disease conditions and is one of the major causes of pouch failure^[8][3].

Treatment options

Treatment for pouchitis depends on the type and severity of inflammation. Currently, there are no medications specifically approved for pouchitis, so all treatment is off-label^[10].

Antibiotics: The first-line treatment for acute pouchitis is antibiotics, specifically ciprofloxacin and metronidazole^[5][14]. These are the most common treatments, and most people improve within 1 to 2 days of starting antibiotics^[14]. The full course of treatment is usually 10 to 14 days, although longer courses are sometimes needed^[14]. Treatment with antibiotics works in most cases^[1].

Alternative antibiotics such as ampicillin or piperacillin can be considered^[5]. People who have regular flare-ups may need ongoing maintenance antibiotic therapy^[14].

Medications to control symptoms: After leaving the hospital, you may take medications like Imodium or Lomotil, or a fiber supplement such as Metamucil, to control the number of bowel movements^[19]. These medications can help reduce nighttime trips to the bathroom when taken before bed^[19].

Probiotics: Using probiotics may help prevent pouchitis from coming back^[14]. While they can help relieve symptoms, probiotics are not available on prescription^[16].

Budesonide: For chronic pouchitis, doctors may prescribe topical or oral budesonide (a type of steroid) for induction therapy^[8].

Biologic medications: Chronic antibiotic-refractory pouchitis often requires induction and maintenance therapy with more advanced medications. These include integrin inhibitors, interleukin inhibitors, or tumor necrosis factor inhibitors^[8]. Newer biologic therapeutics have shown promise in treating chronic pouchitis^[10].

Hyperbaric oxygen therapy: Chronic pouchitis with features of reduced blood flow to tissues (ischemia), abnormal connections between organs (fistulae), or pockets of infection (abscesses) can be treated with hyperbaric oxygen therapy^[8].

Surgery: On rare occasions, pouchitis doesn’t respond to any daily treatment. In these cases, surgeons may need to remove the pouch and create a permanent ileostomy^[14].

Lifestyle considerations: Diet changes can help manage symptoms. Many people find that eating less carbohydrates and fiber while eating more protein can help^[6]. Following a low-residue, soft-consistency diet during healing may be beneficial^[21]. Chewing food slowly and well, consuming small frequent meals, and hydrating between meals can ease the workload on the digestive system^[21].

Outlook and prognosis

For most people, pouchitis is an acute, temporary condition^[1]. The majority of patients with acute pouchitis respond consistently to antibiotic therapy and don’t develop pouchitis again after the first episode^[3][1].

However, some people experience recurring episodes. Between 10% and 20% of people have repeat bouts of pouchitis^[1]. For these individuals, management becomes more complex, especially if they develop chronic antibiotic-dependent or antibiotic-resistant pouchitis.

Recovery from J-pouch surgery and any associated pouchitis takes time and varies greatly from person to person^[15]. Everyone will have their “new normal,” which is why it’s important to be patient and compassionate with yourself during the healing process^[15].

As the pouch heals, it can take time for bowel movements to decrease. Bowel movements may range from 5-6 per day, and it can take up to a year to establish normal bowel function^[19]. Studies show that 93.3% of patients in all age groups maintain a functional pouch after 30 years^[10].

Accurate diagnosis and classification are important for proper management^[8][3]. Known triggering or risk factors, such as C. difficile infection and use of nonsteroidal anti-inflammatory drugs, should be identified and modified or eliminated^[8].