A condition in which the appendix becomes inflamed and filled with pus, causing pain. The appendix is a pouch-like structure attached at the start of the large intestine that has no known purpose. Appendicitis begins with fever and pain near the belly button and then moves toward the lower-right side of the abdomen. This is often accompanied by nausea, vomiting, loss of appetite, fever and chills. Appendicitis is usually treated with antibiotics and surgery is required within 24 hours of its diagnosis. If untreated, the appendix can rupture and cause an abscess or systemic infection (sepsis).

Symptoms

Signs and symptoms of appendicitis may include:

• Sudden pain that begins on the right side of the lower abdomen
• Sudden pain that begins around your navel and often shifts to your lower right abdomen
• Pain that worsens if you cough, walk or make other jarring movements
• Nausea and vomiting
• Loss of appetite
• Low-grade fever that may worsen as the illness progresses
• Constipation or diarrhea
• Abdominal bloating
• Flatulence

The site of your pain may vary, depending on your age and the position of your appendix. When you’re pregnant, the pain may seem to come from your upper abdomen because your appendix is higher during pregnancy.

When to see a doctor

Make an appointment with a doctor if you or your child has worrisome signs or symptoms. Severe abdominal pain requires immediate medical attention.

Causes

A blockage in the lining of the appendix that results in infection is the likely cause of appendicitis. The bacteria multiply rapidly, causing the appendix to become inflamed, swollen and filled with pus. If not treated promptly, the appendix can rupture.

Complications

Appendicitis can cause serious complications, such as:

• A ruptured appendix. A rupture spreads infection throughout your abdomen (peritonitis). Possibly life-threatening, this condition requires immediate surgery to remove the appendix and clean your abdominal cavity.
• A pocket of pus that forms in the abdomen.If your appendix bursts, you may develop a pocket of infection (abscess). In most cases, a surgeon drains the abscess by placing a tube through your abdominal wall into the abscess. The tube is left in place for about two weeks, and you’re given antibiotics to clear the infection.

Once the infection is clear, you’ll have surgery to remove the appendix. In some cases, the abscess is drained, and the appendix is removed immediately.