Appendicitis is inflammation of the appendix. The appendix is a small pouch attached to your large intestine.

Appendicitis is one of the most common causes of emergency abdominal surgery in the United States. Appendicitis usually occurs when the appendix becomes blocked by feces, a foreign object, or rarely, a tumor.

The symptoms of appendicitis vary. It can be hard to diagnose appendicitis in young children, the elderly, and women of childbearing age.

Typically, the first symptom is pain around your belly button. (See: abdominal pain.) The pain may be vague at first, but becomes increasingly sharp and severe. You may have reduced appetite, nausea, vomiting, and a low-grade fever.

As the inflammation in the appendix increases, the pain tends to move into your right lower abdomen and focuses directly above the appendix at a place called McBurney's point.

If the appendix ruptures, the pain may lessen briefly and you may feel better. However, once the lining of the abdominal cavity becomes inflammed and infected (a condition called peritonitis), the pain worsens and you become sicker.

Abdominal pain may be worse when walking or coughing. You may prefer to lie still because sudden movement causes pain.

Later symptoms include:

• Chills
• Constipation
• Diarrhea
• Fever
• Loss of appetite
• Nausea
• Shaking
• Vomiting

If you have appendicitis, your pain increases when the doctor suddenly releases the pressure after gently pressing on your lower right belly area. If peritonitis is present, touching the belly area may cause a spasm of the muscles.

A rectal examination may reveal abdominal or pelvic tenderness on the right side of your body.

Doctors can usually diagnose appendicitis by your description of the symptoms, the physical exam, and laboratory tests alone. In some cases, additional tests may be needed. These may include:

• Abdominal CT scan
• Abdominal ultrasound
• Diagnostic laparoscopy

Note: The U.S. Food and Drug Administration recalled a drug used during some appendicitis-related imaging tests after reports of life-threatening side effects and deaths. The drug, called NeutroSpec, was used to help diagnose appendicitis in patients ages 5 and older who may have had the condition but did not show the usual signs and symptoms.

If you have an uncomplicated case, a surgeon will remove your appendix soon after your doctor thinks you might have the condition. For information on this type of surgey see: appendectomy.

If the operation reveals that your appendix is normal, the surgeon will remove the appendix and explore the rest of your abdomen for other causes of your pain.

If a CT scan shows that you have an abscess from a ruptured appendix, you may be treated first and have your appendix removed after the infection and inflammation have gone away.

If your appendix is removed before it ruptures, you will likely get well very soon after surgery. If your appendix ruptures before surgery, you will probably recover more slowly, and are more likely to develop an abscess or other complications.

• Abnormal connections between abdominal organs or between these organs and the skin surface
• Abscess
• Infection of the surgical wound
• Peritonitis

Call your local emergency department or emergency medical service (such as 911) if:

• Your pain is severe, sudden and sharp
• You have a fever along with your pain
• You are vomiting blood or have bloody diarrhea
• You have a rigid, hard abdomen that is tender to touch
• You are unable to pass stool, especially if you are also vomiting
• You have chest, neck, or shoulder pain
• You are dizzy or light-headed

Call your health care provider if you develop abdominal pain in the lower right portion of your belly, or any other symptoms of appendicitis. Also call your doctor if:

• You have nausea and lack of appetite
• You are unintentionally losing weight
• You have yellowing of your eyes or skin
• You have bloating for more than 2 days
• You have diarrhea for more than 5 days, or if your infant or child has had diarrhea for 2 days or vomiting for 12 hours (Call right away if a baby under 3 months has diarrhea or vomiting)
• You have had abdominal discomfort for more than 1 week
• You have burning with urination or you are urinating more often than usual
• You have pain and may be pregnant
• Your pain gets worse when you take antacids or eat something

Wolfe JM, Henneman PL. Acute Appendicitis. In: Marx J. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 6th ed. St. Louis, Mo: Mosby; 2006: Chap.92.

Maa J, Kirkwood JS. The Appendix. In: Townsend CM, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery, 18th ed. St. Louis, Mo: WB Saunders; 2008:Chap 49.

US Food and Drug Administration. FDA Issues Public Health Advisory on use of NeutroSpec, [Technetium (99m TC) Fanolesomab], Imaging Agent for Diagnosis of Appendicitis. Rockville, MD: National Press Office; December 19, 2005. Press Release P05-104.

Lyon C, Clark DC. Diagnosis of acute abdominal pain in older patients. Am Fam Physician. 2006 Nov 1;74(9):1537-44. Review.

Ebell MH. Diagnosis of appendicitis: part 1. History and physical examination. Am Fam Physician. 2008 Mar 15;77(6):828-30. Review.

Bundy DG, Byerley JS, Liles EA, Perrin EM, Katznelson J, Rice HE. Does this child have appendicitis? JAMA. 2007 Jul 25;298(4):438-51. Review.