Ileo-anal pouch
Encyclopedia
The ileal pouch-anal anastomosis (IPAA), also known as an ileo-anal pouch, restorative proctocolectomy, ileal-anal pullthrough, or sometimes referred to as a j-pouch, s-pouch, w-pouch or an internal pouch, is an internal reservoir; usually situated where the rectum would normally be. It is formed by folding loops of small intestine (the ileum
) back on themselves and stitching or stapling them together. The internal walls are then removed thus forming a reservoir. The reservoir is then stitched or stapled into the perineum where the rectum was.
which may require surgical removal include:
There is debate about whether patients suffering from Crohn's disease
are suitable candidates for an ileo-anal pouch due to the risk of the disease occurring in the pouch, which could make matters even worse. An alternative to an ileo-anal pouch is an ileostomy
.
In some cases where the pouch was formed to manage colitis, inflammation can return to the pouch in a similar way to the original inflammation in the colon. This is known as pouchitis
.
where, in the absence of a colon, intestinal waste is emptied into a bag attached to the abdomen.
This work was pioneered by Sir Alan Parks at St. Mark's Hospital in London in the early 1980s, the pouch was known as Parks' Pouch.
(removal of the large intestine and rectum), and fashioning of the pouch. The patient is given a temporary defunctioning ileostomy
(also known as a "loop ileostomy"). After a period of usually 6-12 weeks the second step (sometimes called the "takedown") is performed, in which the ileostomy is reversed. The reason for the temporary ileostomy is to allow the newly constructed pouch to fully heal without waste passing through it, thus avoiding infection.
Some surgeons prefer to perform a subtotal colectomy (removing all the colon except the rectum
), since removal of the rectum can lead to complications with the anal sphincters. When a colectomy is performed as an emergency (which can arise from Toxic megacolon
and other complications), and/or when the patient is extremely ill, the colectomy and pouch construction are performed in separate stages resulting in a three-part surgery.
does not absorb as much water as the colon, the stools tend to be less formed, and sometimes fluid. The normal pouch output is described to be of a consistency similar to porridge. People who find that the consistency remains loose and/or who are experience motions too frequently usually take loperamide
or codeine phosphate to thicken the stool and slow the bowel movement.
Because the ileum does not absorb as much of the gastric acid
produced by the stomach
as the colon did, pouch output also tends to burn the anal region slightly, and many patients find it helpful to wash the area regularly, sometimes using protective barrier cream.
Many patients choose to eat more white carbohydrates, because this thickens the pouch output and reduces the risk of dehydration or the aforementioned burning of the anal region. It is also common among pouch-owners to eat little and often, or "graze", rather than having three large meals a day. Some patients avoid eating much after 6-7pm to avoid having to get up during the night.
Immediately after surgery, patients are encouraged to eat low fiber, high protein/carbohydrate meals, but after the pouch function has settled, most are able to reintroduce a fully varied diet. There are some foods that are known to irritate the pouch, however, and though they may be introduced carefully, are best avoided immediately following surgery.
and metronidazole
.
Ileum
The ileum is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of ileum.The ileum follows the duodenum...
) back on themselves and stitching or stapling them together. The internal walls are then removed thus forming a reservoir. The reservoir is then stitched or stapled into the perineum where the rectum was.
Reasons for pouch construction
Ileo-anal pouches are constructed for people who have had their large intestine surgically removed due to disease or injury. Diseases and conditions of the large intestineLarge intestine
The large intestine is the third-to-last part of the digestive system — — in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body...
which may require surgical removal include:
- Ulcerative colitisUlcerative colitisUlcerative colitis is a form of inflammatory bowel disease . Ulcerative colitis is a form of colitis, a disease of the colon , that includes characteristic ulcers, or open sores. The main symptom of active disease is usually constant diarrhea mixed with blood, of gradual onset...
- Crohn's diseaseCrohn's diseaseCrohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
- Familial adenomatous polyposisFamilial adenomatous polyposisFamilial adenomatous polyposis is an inherited condition in which numerous polyps form mainly in the epithelium of the large intestine. While these polyps start out benign, malignant transformation into colon cancer occurs when not treated....
- Colon cancer
- Toxic megacolonToxic megacolonToxic megacolon is an acute form of colonic distension. It is characterized by a very dilated colon , accompanied by abdominal distension , and sometimes fever, abdominal pain, or shock....
There is debate about whether patients suffering from Crohn's disease
Crohn's disease
Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
are suitable candidates for an ileo-anal pouch due to the risk of the disease occurring in the pouch, which could make matters even worse. An alternative to an ileo-anal pouch is an ileostomy
Ileostomy
An ileostomy is a surgical opening constructed by bringing the end or loop of small intestine out onto the surface of the skin. Intestinal waste passes out of the ileostomy and is collected in an external pouching system stuck to the skin...
.
In some cases where the pouch was formed to manage colitis, inflammation can return to the pouch in a similar way to the original inflammation in the colon. This is known as pouchitis
Pouchitis
Pouchitis is inflammation of the ileal pouch, which is created in the management of patients with ulcerative colitis, indeterminate colitis, or, rarely, other colitides....
.
History
The surgical procedure for forming an ileo-anal pouch was developed as an alternative to the ileostomyIleostomy
An ileostomy is a surgical opening constructed by bringing the end or loop of small intestine out onto the surface of the skin. Intestinal waste passes out of the ileostomy and is collected in an external pouching system stuck to the skin...
where, in the absence of a colon, intestinal waste is emptied into a bag attached to the abdomen.
This work was pioneered by Sir Alan Parks at St. Mark's Hospital in London in the early 1980s, the pouch was known as Parks' Pouch.
Surgical Procedure
The entire procedure can be performed in one operation, but is usually split into two or three. When done as a two-step, the first operation (step one) involves a proctocolectomyProctocolectomy
Proctocolectomy is the surgical removal of the rectum and all or part of the colon. It is a most widely accepted surgical method for ulcerative colitis and Familial adenomatous polyposis .- References :...
(removal of the large intestine and rectum), and fashioning of the pouch. The patient is given a temporary defunctioning ileostomy
Ileostomy
An ileostomy is a surgical opening constructed by bringing the end or loop of small intestine out onto the surface of the skin. Intestinal waste passes out of the ileostomy and is collected in an external pouching system stuck to the skin...
(also known as a "loop ileostomy"). After a period of usually 6-12 weeks the second step (sometimes called the "takedown") is performed, in which the ileostomy is reversed. The reason for the temporary ileostomy is to allow the newly constructed pouch to fully heal without waste passing through it, thus avoiding infection.
Some surgeons prefer to perform a subtotal colectomy (removing all the colon except the rectum
Rectum
The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...
), since removal of the rectum can lead to complications with the anal sphincters. When a colectomy is performed as an emergency (which can arise from Toxic megacolon
Toxic megacolon
Toxic megacolon is an acute form of colonic distension. It is characterized by a very dilated colon , accompanied by abdominal distension , and sometimes fever, abdominal pain, or shock....
and other complications), and/or when the patient is extremely ill, the colectomy and pouch construction are performed in separate stages resulting in a three-part surgery.
Bowel motions
Immediately after the surgery is complete, the patient tends to pass liquid stool with frequent urgency, and he or she may have 8 to 15 bowel movements per day, but this eventually decreases with time. Because the ileo-anal pouch is considerably smaller a reservoir than the colon, patients tend to have more frequent bowel motions; typically 6-8 times a day. Also because the ileumIleum
The ileum is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of ileum.The ileum follows the duodenum...
does not absorb as much water as the colon, the stools tend to be less formed, and sometimes fluid. The normal pouch output is described to be of a consistency similar to porridge. People who find that the consistency remains loose and/or who are experience motions too frequently usually take loperamide
Loperamide
Loperamide , a synthetic piperidine derivative, is an opioid drug used against diarrhea resulting from gastroenteritis or inflammatory bowel disease. In most countries it is available generically and under brand names such as Lopex, Imodium, Dimor, Fortasec, and Pepto Diarrhea Control...
or codeine phosphate to thicken the stool and slow the bowel movement.
Because the ileum does not absorb as much of the gastric acid
Gastric acid
Gastric acid is a digestive fluid, formed in the stomach. It has a pH of 1 to 2 and is composed of hydrochloric acid , and large quantities of potassium chloride and sodium chloride...
produced by the stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
as the colon did, pouch output also tends to burn the anal region slightly, and many patients find it helpful to wash the area regularly, sometimes using protective barrier cream.
Diet
Because more water is lost through pouch output, patients can get dehydrated easily and can also suffer salt deficiency. For this reason, some are encouraged to add extra salt to meals. Persistent dehydration is often supplemented with an electrolyte mix drink.Many patients choose to eat more white carbohydrates, because this thickens the pouch output and reduces the risk of dehydration or the aforementioned burning of the anal region. It is also common among pouch-owners to eat little and often, or "graze", rather than having three large meals a day. Some patients avoid eating much after 6-7pm to avoid having to get up during the night.
Immediately after surgery, patients are encouraged to eat low fiber, high protein/carbohydrate meals, but after the pouch function has settled, most are able to reintroduce a fully varied diet. There are some foods that are known to irritate the pouch, however, and though they may be introduced carefully, are best avoided immediately following surgery.
- Increased stool output can be caused by fibrous foods (such as pulses, green leaves, raw vegetables etc.) and also by spicy foods, alcohol and caffeineCaffeineCaffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...
. - Anal irritation can be caused by nuts, seeds, citric acid, raw fruit and spicy food.
- Increased gas can be caused by fizzy drinks, milk, beer, broccoli, cauliflower, sprouts, cabbage etc.
- Increased odor can be caused by foods such as fish, onions, garlic and eggs.
Pouchitis
Pouchitis is an inflammation of the ileo-anal pouch, which occurs particularly in cases where the pouch has been created to manage colitis. The symptoms are normally somewhat similar but less acute than those of colitis, and include (sometimes bloody) diarrhoea, urgency or difficulty in passing stools, and, in few cases, pain. The standard treatment for pouchitis is a 7 to 10 day course of a combination ciprofloxacinCiprofloxacin
Ciprofloxacin is a synthetic chemotherapeutic antibiotic of the fluoroquinolone drug class.It is a second-generation fluoroquinolone antibacterial. It kills bacteria by interfering with the enzymes that cause DNA to rewind after being copied, which stops synthesis of DNA and of...
and metronidazole
Metronidazole
Metronidazole is a nitroimidazole antibiotic medication used particularly for anaerobic bacteria and protozoa. Metronidazole is an antibiotic, amebicide, and antiprotozoal....
.