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Patient education: Small bowel obstruction (The Basics)

Patient education: Small bowel obstruction (The Basics)

What is a small bowel obstruction? — A small bowel obstruction (SBO) is a condition in which the small intestine gets blocked. "Small bowel" is another term for the small intestine (figure 1). In an SBO, air, fluid, and food get stuck in the intestine. They can't move through the small intestine the way they normally would.

The intestine can be partly or completely blocked in an SBO. A complete block can lead to serious problems. That's because:

The intestine can get swollen from the trapped air, fluid, and food. This swelling can make the intestine less able to absorb fluid, which can lead to dehydration and kidney failure.

If the intestine wall tears, the fluid in the intestine can leak out. This can cause a belly infection.

When the intestine is blocked, the blood vessels that bring oxygen to the intestine can get blocked, too. Without blood, parts of the intestine can die.

In some cases, the small intestine looks blocked on tests even when it isn't. This could be from either intestinal "ileus" or "pseudo-obstruction." This article is only about real obstruction.

What causes an SBO? — The most common causes of an SBO are:

Past surgery in the belly – After surgery, scar tissue can form in the belly and press on the intestine.

Hernias – A hernia is an opening in the muscle or tissue that covers the muscle. Part of the intestine can slide through that opening and get trapped in a hernia. A hernia inside the belly can also cause SBO.

Twisting of the intestines

Tumor – Tumors (cancerous and noncancerous) can grow inside or outside the intestine and block it.

What are the symptoms of an SBO? — Symptoms depend on where your intestine is blocked and how blocked it is. The most common symptoms are:

Nausea and vomiting

Belly pain

Belly swelling and bloating

Not being able to have a bowel movement or pass gas

Will I need tests? — Yes. Your doctor will ask about your symptoms and do an exam. If your doctor thinks that you have an SBO, they will do imaging tests of your belly and blood tests.

The imaging tests can include an X-ray, CT scan, or a series of X-rays called a "GI series." For the CT scan and GI series, you might drink a liquid called "contrast" beforehand. The contrast will show up on the CT scan or X-rays. It can help the doctor see what's causing the blockage.

How is an SBO treated? — Treatment depends on the blockage and your symptoms.

If you have an SBO, you will be treated in the hospital. Your doctor will give you fluids and medicines. You will not be allowed to eat or drink. You will also get something called a "nasogastric tube." This is a thin tube that goes in your nose, down your esophagus, and into your stomach. The tube can suck up the fluid and air in your stomach. This will make your stomach feel better and help keep you from vomiting.

Most people will not need any other treatment. That's because, many times, an SBO can get better on its own. This is often the case for a partial SBO, or an SBO that has happened after earlier belly surgery.

Some people will need surgery. You are likely to need surgery if you have a belly infection, you have a complete blockage, or your SBO does not get better with fluids and the nasogastric tube in a few days. You also need surgery if the SBO is caused by a hernia, a tumor, or a twist in the intestine.

During surgery, your doctor will remove what is causing the blockage and, if needed, any unhealthy parts of your small intestine. If your doctor removes the unhealthy intestine, they will usually reconnect your intestines so you will not need an ostomy bag. (An ostomy bag is a bag that attaches to the skin and collects bowel movements. It is used if the intestines cannot be reconnected after a surgery.)

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This topic retrieved from UpToDate on: Jan 01, 2023.
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