Ileostomy - Why an ileostomy may be needed

An ileostomy may be needed if the colon is damaged, inflamed, or doesn't work properly.

Some of the most common reasons why surgery to form an ileostomy is carried out are described below.

Crohn’s disease

Crohn’s disease is a long-term condition where the lining of the digestive system becomes inflamed. Common symptoms include:

Crohn's disease can usually be controlled with medication, but surgery to create an ileostomy may sometimes be recommended to temporarily divert digestive waste away from the inflamed section of the digestive system to give it a chance to heal.

Ulcerative colitis

Ulcerative colitis is a long-term condition where the colon (large intestine or large bowel) becomes inflamed. Common symptoms include:

  • bloody diarrhoea
  • abdominal pain
  • a frequent need to pass stools

In most cases symptoms can be controlled with medication. However, surgery to remove the colon and form an ileostomy or ileo-anal pouch (an internal pouch to store stools created using the end of the small intestine) may be recommended if the condition is particularly severe or doesn't respond to medication.

Bowel cancer

Bowel cancer is a type of cancer that develops inside the colon or rectum (the final section of the bowel through which stools are passed).

Chemotherapy or radiotherapy, or a combination of both, are usually used to shrink the cancer first, before the affected section of bowel is removed.

Depending on the size and position of the section of bowel that is removed, a temporary or permanent ileostomy, or an ileo-anal pouch, may be formed during the operation.

In some cases, a section of your colon may need to be diverted out of your abdomen (tummy). This is known as a colostomy, rather than an ileostomy.

Less common uses

Some of the less common reasons why surgery to form an ileostomy is needed are described below.

Familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is a rare condition that triggers the growth of non-cancerous lumps of tissue inside the colon.

Although the lumps are non-cancerous to begin with, there is high risk that, over time, at least one will turn cancerous. More than 99% of people with FAP will have bowel cancer by the time they are 50 years old.

Due to the high risk of developing cancerous lumps, it's usually recommended that a person diagnosed with FAP has their colon removed. It is usually replaced with an ileo-anal pouch, or occasionally a permanent ileostomy.

Bowel obstruction

A bowel obstruction occurs when part of the digestive system becomes blocked by food, fluids, or waste products. This can happen if part of the person's digestive system is scarred or inflamed, or if their digestive system is unusually narrow.

If the colon becomes completely blocked, it is usually necessary to remove the colon and form an ileostomy. This can be temporary or permanent, depending on the underlying cause of the obstruction.


A significant injury to the colon, such as a puncture or impact injury, can result in the colon becoming permanently damaged.

In these cases, it may be necessary to remove the colon and form an ileostomy. Whether this is a temporary or permanent ileostomy will depend on the type and extent of the injury.

Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Diarrhoea is the passing of frequent watery stools when you go to the toilet.
Familial is when a non-inherited disease or condition tends to affect more members of the same family than other families in the general population.
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.
Pain is an unpleasant physical or emotional feeling that your body produces as a warning sign that it has been damaged.

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