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Appendicitis Causes, Symptoms, and Treatments

The appendix is a finger-sized tube of the digestive tract in the lower-right abdomen. It's attached to the large intestine, and when it gets infected, you get appendicitis.

Doctors diagnose appendicitis when a person has symptoms, and a scan reveals a swollen appendix. It often requires surgery to remove the appendix.

This surgery is common in children and young adults.

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What Is Appendicitis?

It's an infection of the appendix. Between 5% and 9% of Americans will have appendicitis.

Researchers haven't found a specific role for the appendix.

Some suggest it could play a role in the immune system. It may also bolster the gut's helpful bacteria.

If a doctor doesn't treat or remove an infected appendix fast enough, it can burst. Bursting can spread infection elsewhere in the body, a life-threatening problem.

This danger is why seeking care right away for suspected appendicitis is vital.

What causes appendicitis?

A germ causes an appendix infection, mostly bacterial but sometimes a virus, parasite, or fungus. These germs grow and expand inside the appendix when the opening of it gets blocked.

Many substances can block the appendix, such as:

  • Hard stool.
  • Dried mucus.
  • An inflamed lymph node.

The infection triggers the body's immune system to respond.

As immune-fighting cells flood the appendix, it swells. This swelling leads to pain in the lower right side of the belly.

What are appendicitis risk factors and complications?

Appendicitis often occurs in otherwise healthy people. Most times, there isn't a prime reason or cause for it.

Children and young adults aged 10 to 30 are most likely to get appendicitis. But it can occur at any age.

Research shows that people who have a diet low in fiber are more likely to get appendicitis. While a high-fiber diet may reduce your risk, it doesn't fully remove the risk of appendicitis.

Once an infection starts in the appendix, it becomes inflamed by the immune system's reaction.

An inflamed appendix can burst. If doctors don't remove the infected parts of a burst appendix and clean the abdomen, the infection can spread.

The spreading infection, and the immune system's response to it, can damage other organs.

If untreated, a ruptured appendix can be fatal.

Why choose UPMC for appendicitis care?

At UPMC, our experts:

  • Have the means to fast-track testing and treatment for people who may have appendicitis to get a diagnosis fast.
  • Have advanced expertise in minimally invasive surgeries to remove an infected appendix and more complex surgeries if it has ruptured.
  • Routinely perform appendix removal surgery on children and adults.

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Appendicitis Symptoms and Diagnosis

What are the signs and symptoms of appendicitis?

The first symptom is often stomach pain. It may start on the right side of the abdomen or at the belly button and move to the lower right side.

The pain gets worse over hours or days and often becomes severe.

People with appendicitis may also have symptoms such as:

  • Nausea and vomiting.
  • The urge to have a bowel movement.
  • Constipation or diarrhea.
  • Fever.
  • Loss of appetite.

How do you diagnose appendicitis?

Your doctor will:

  • Start with a physical exam. They'll press on different parts of the belly to see where it's tender or painful.
  • Ask about any other symptoms you're having.
  • Order tests if they suspect but need to confirm appendicitis.

Imaging tests

Doctors often order a CT scan to see the swollen appendix. They'll also check for other issues in the abdominal area that may be causing pain. CT scans are not used on pregnant women or children.

An ultrasound is a safe test that uses sound waves to see inside your body and does not use radiation. Sometimes, ultrasound scans don't confirm the diagnosis.

Blood and urine tests to help diagnose appendicitis

Your doctor may also order blood tests to look for increased white blood cells, a sign of infection.

They may also test your urine to rule out kidney or bladder problems.

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What Are the Treatment Options for Appendicitis?


Your doctor will first give you an IV of antibiotics. This may be all you need to treat mild cases of the infection.

In advanced cases, such as the presence of an abscess, image-guided drainage may be used to treat the acute infection.

Surgery to treat appendicitis

Doctors often urge surgery to remove the appendix — called an appendectomy.

They prefer to stay on the side of caution because the risks of a ruptured appendix are high. That's why they may suggest an appendectomy even when they suspect appendicitis but can't confirm.

In most cases, surgeons will do minimally invasive surgery using tiny cuts rather than a large cut of open surgery.

Compared to open surgery, people heal much faster and can often go home after a day.

Scientists think the appendix may play a role in storing healthy gut bacteria or in the immune system.

But, long-term studies show those without their appendix are just as healthy as those with it. The upside is that once surgeons remove the appendix, there's no threat of appendicitis in the future.

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