The pathogenesis of acute cholecystitis is primarily due to obstruction of biliary outflow by a stone. Other rare causes may be stricture, kinking of the cystic duct, intussusception of a polyp, torsion of the gallbladder, pressure of an overlying lymph node on the cystic duct, or inspissated and concentrated bile. As the gallbladder distends following the obstruction, the blood vessels in the gallbladder wall become compressed, giving rise to a patch of gangrene on the fundus which can rupture and produce bile peritonitis. In addition to these mechanical and vascular factors various investigators have favored infection or chemical irritation as the cause of this disease.
Graham and Peterman1 were probably the last to emphasize the role of infection and to delineate the anatomical pathways of such infection. Since infection was present in the wall of the gallbladder before it involved the mucosa, they believed that the route of infection