Gastrointestinal Imaging

Cholecystitis, acute, acalculous

acute inflammation of the gallbladder in the absence of stones. About 50% of children with acute cholecystitis have acalculous disease. It is most likely to occur in adults who are critically ill or who have recently undergone stress in the form of severe trauma, burns or major surgery. The most common predisposing factors are prolonged fasting, immobility and haemodynamic instability. Direct injury of the gallbladder mucosa caused by concentrated stagnant bile and ischaemia of the gallbladder wall are assumed to be the direct causes of acute acalculous cholecystitis. Gallbladder wall necrosis occurs in about 60% of cases, gangrene and perforation are common and mortality is as high as 3050%.

On ultrasound nonspecific signs of distension of the gallbladder and sludge may be visible. Other ultrasound signs that may suggest the diagnosis of acute acalculous cholecystitis include gallbladder wall thickening with hypoechoic regions within the wall and the presence of pericholecystic fluid or of intraluminal membranes. Although cholescintigraphy is very sensitive it is considered that findings are nonspecific. CT may be useful in showing pericholecystic fluid collections, perforation of the gallbladder wall or inflammation of pericholecystic fat but CT is rarely performed under these circumstances because of the poor general condition of the patient.

ALB