Pathophysiology
Acute cholecystitis develops when a gallstone lodges in the cystic duct and obstructs it, causing gallbladder distension, inflammation, and often secondary bacterial infection. This differs from biliary colic, in which a stone transiently obstructs and then falls back; in cholecystitis the obstruction persists, producing sustained inflammation. Acalculous cholecystitis, without stones, occurs in critically ill patients.
Clinical Features
The hallmark is persistent right-upper-quadrant or epigastric pain lasting more than several hours, often after a fatty meal, with fever, nausea, and vomiting — a more systemic and prolonged picture than the self-limited pain of biliary colic. The classic sign is Murphy sign: the patient stops inspiration when the examiner palpates the right upper quadrant during a deep breath, due to pain as the inflamed gallbladder meets the hand.
Diagnosis
Right-upper-quadrant ultrasound is the first-line test, showing gallstones, a thickened gallbladder wall, pericholecystic fluid, and a sonographic Murphy sign. Laboratory tests often show leukocytosis and mildly elevated liver enzymes. When ultrasound is equivocal, a HIDA (cholescintigraphy) scan can confirm the diagnosis by demonstrating non-filling of the gallbladder due to cystic duct obstruction.
Treatment
Initial management includes bowel rest, intravenous fluids, analgesia, and antibiotics. Definitive treatment is laparoscopic cholecystectomy, generally performed early during the same hospitalization. In patients who are poor surgical candidates, a percutaneous cholecystostomy tube can drain the gallbladder as a temporizing measure. Complications of untreated disease include gangrene, perforation, and gallstone-related biliary complications.