Acute cholecystitis is a major complication of cholelithiasis (i.e., gallstones); symptomatic gallstones are common before developing cholecystitis.

Patients typically present with pain and localised tenderness, with or without guarding, in the upper right quadrant.

There may be evidence of a systemic inflammatory response with fever, elevated white cell count, and raised C-reactive protein.

Ultrasound is the definitive initial test. Magnetic resonance cholangiopancreatography may be required. In a patient with suspected sepsis, use computed tomography (or magnetic resonance imaging)to identify the cause.

Treatment is with antibiotics, analgesia, and fluid resuscitation as required, likely to be followed by an early cholecystectomy.

Acute cholecystitis is acute gallbladder inflammation, and one of the major complications of cholelithiasis or gallstones. It develops in up to 10% of patients with symptomatic gallstones.[1]Ziessman HA. Acute cholecystitis, biliary obstruction and biliary leakage. Semin Nucl Med. 2003 Oct;33(4):279-96. http://www.ncbi.nlm.nih.gov/pubmed/14625840?tool=bestpractice.com In most cases (90%), it is caused by complete cystic duct obstruction usually due to an impacted gallstone in the gallbladder neck or cystic duct, which leads to inflammation within the gallbladder wall.[1]Ziessman HA. Acute cholecystitis, biliary obstruction and biliary leakage. Semin Nucl Med. 2003 Oct;33(4):279-96. http://www.ncbi.nlm.nih.gov/pubmed/14625840?tool=bestpractice.com In 5% of cases, bile inspissation (due to dehydration) or bile stasis (due to trauma or severe systemic illness) can block the cystic duct, causing an acalculous cholecystitis.[1]Ziessman HA. Acute cholecystitis, biliary obstruction and biliary leakage. Semin Nucl Med. 2003 Oct;33(4):279-96. http://www.ncbi.nlm.nih.gov/pubmed/14625840?tool=bestpractice.com [Figure caption and citation for the preceding image starts]: The biliary tree [Citation ends].