<prompt> All are true about acute acalculous cholecystitis exceptDistended GBVascular causeSeen in bed ridden patientsRapid course  <response>: Distended GB is seen in scintigraphy Cholescintigraphy demonstrates absent gallbladder filling in acalculous cholecystitis Acalculous cholecystitis Acute inflammation of gallbladder without stones Clinical features Similar to acute calculous cholecystitis Patients may present with only unexplained fever, leucocytosis and hyperamylasemia and RUQ tenderness If untreated, rapid progression to gangrene and perforation may occur Ref: Sabiston 20th edition Pgno : 1508 