ACUTE CALCULOUS CHOLECYSTITIS
The prevalence of gallstones in the general population is approximately 10–15%, and is higher in people with the following risk factors: female gender, multiparity, obesity, recent pregnancy, and hemolytic diseases (e.g., sickle cell disease). Of people with gallstones, 10–20% will develop complications such as biliary colic, cholecystitis, cholangitis, or gallstone pancreatitis.
Acute calculous cholecystitis is defined by sustained obstruction of the cystic duct or neck of the gallbladder with gallstones or sludge. In contrast, biliary colic is pain secondary to transient obstruction of the gallbladder. Acute cholecystitis is primarily a localized acute inflammatory process caused by gallbladder obstruction and subsequent distension, but is clinically managed as an infection. The pathophysiologic role of bacteria cultured from bile remains unknown.
Although most patients with acute cholecystitis present with right upper quadrant tenderness, few actually present with the classic triad of fever, right upper quadrant pain, and leukocytosis. The pain of acute cholecystitis may radiate to the back and the right shoulder due to secondary irritation of the diaphragm. Acute cholecystitis can be distinguished from biliary colic by constant pain in the right upper quadrant and the presence of Murphy's sign, defined as inspiration limited by pain on palpation of the right upper quadrant.