Blocked bowel (bowel obstruction)

Some people are diagnosed with bowel cancer after being admitted to hospital with a bowel obstruction. Or an obstruction may develop later on.

But as well as bowel cancer some other cancers might also cause a bowel obstruction, including:

• pancreatic cancer
• cancers that start in the lower pelvis (the area between the hips) – for example, ovarian cancer, womb cancer or cervical cancer
• lymphoma.

Another possible cause of bowel obstruction is adhesions. These are areas of scar tissue that grow in the tummy (abdomen) or pelvis after surgery or radiotherapy to these areas. Adhesions can cause tissue in the tummy to stick together.

Your doctor will examine your tummy and ask questions about your symptoms and medical history.

They may also do a rectal examination. This is when a doctor gently inserts a gloved finger into your rectum to feel for anything abnormal.

You will have blood tests to check for infection or anaemia and to check how well organs such as your kidneys are working.

Your doctor may arrange further tests, such as:

• a CT scan – the most commonly used scan to diagnose bowel obstruction
• an x-ray.

Some people need surgery to remove the obstruction straight away. This is to prevent serious complications. Bowel obstruction may cause a hole to develop in the colon. This is called a perforated bowel. It can allow the contents of the bowel to leak into the tummy area. This can cause infection.

Surgery aims to remove the blocked section of bowel. If the cancer has not spread, the surgeon will try to remove all the cancer. If the cancer is more advanced, it might not be possible to do this. But the surgeon will try to remove the part of the bowel that is blocked.

After surgery, most people have a temporary or permanent stoma. A stoma is an opening made through the tummy wall. It connects the bowel to the surface of the tummy. 

If you have a stoma, stools (poo) will no longer pass out of the rectum and anus in the usual way. Instead, they pass out of the stoma, into a disposable bag you wear over the stoma.

Surgery to remove a bowel obstruction is a major operation. Your surgeon and nurse will explain what it involves. You need to know:

• how it may affect you
• the benefits of surgery
• any possible risks.

The nurses will give you drugs to help control symptoms such as pain and heartburn. You will also be given drugs to stop you feeling sick. You usually have these drugs as an injection or through a small pump that delivers them under the skin.

To begin with, you will usually have a drip (infusion) of fluids into a vein in your arm. You will not usually be able to eat for or drink for a few days. This helps to rest the bowel.

A nurse or doctor may put a narrow tube through your nose down into your stomach. They can use this to empty the contents of your stomach to prevent you from being sick. You might also be given antibiotics to prevent an infection.

If the bowel is only partly blocked, resting the bowel may be all the treatment you need.

You might also meet a dietitian for advice about your diet. Some people may be advised to eat a low-fibre or low-roughage diet. This might help make the stools softer so they can pass through the bowel more easily.

If constipation is causing the obstruction or making it worse, you might be given medicines (laxatives) or treatments to relieve it. Your doctor can prescribe laxatives that soften the stool but do not cause tummy cramps.

Sometimes drugs called steroids can also be used to reduce inflammation in your bowel.