Acute cholecystitis is a sudden inflammation of the gallbladder that causes severe abdominal pain.

In 90% of cases, acute cholecystitis is caused by gallstones in the gallbladder. Severe illness, alcohol abuse and, rarely, tumors of the gallbladder may also cause cholecystitis.

Acute cholecystitis causes bile to become trapped in the gallbladder. The build up of bile causes irritation and pressure in the gallbladder. This can lead to bacterial infection and perforation of the organ.

Gallstones occur more frequently in women than men. Gallstones become more common with age in both sexes. Native Americans have a higher rate of gallstones.

The main symptom is abdominal pain -- particularly after a fatty meal -- that is located on the upper right side of the abdomen. Occasionally, nausea and vomiting or fever may occur.

A doctor's examination of the abdomen by touch (palpation) may reveal tenderness.

Tests that detect the presence of gallstones or inflammation include:

• Abdominal ultrasound
• Abdominal CT scan
• Abdominal x-ray
• Oral cholecystogram
• Gallbladder radionuclide scan
• A CBC shows infection by an elevated white blood cell count.