acalculous cholecystitis

etiology:

depressed motility and starvation: trauma, burns, surgery, TPN, anesthesia, narcotics
decreased blood flow through cystic artery: CHF, arteriosclerosis, polyarteritis nodosa, SLE, diabetes, shock
obstruction of cystic duct by extrinsic inflammation, lymphadenopathy, metastases
infection: Salmonella, cholera, Kawasaki syndrome