Acute cholecystitis occurs in approximately one third of patients with gallstones and is caused by obstruction of the cystic duct by an impacted calculus, resulting in gallbladder wall inflammation and potential infection or necrosis. Symptoms include pain similar to biliary colic but more severe, as well as vomiting, tenderness in the upper right abdomen, and low grade fever. Diagnosis is typically made using ultrasound to detect gallstones, thickened gallbladder walls, and fluid around the gallbladder. Treatment involves laparoscopic cholecystectomy to remove the gallbladder through several small incisions, which is preferred over traditional open cholecystectomy requiring a larger incision.