Emphysematous cholecystitis is a rare form of acute cholecystitis where gallbladder wall necrosis causes gas formation in the lumen or wall. It is a surgical emergency, due to the high mortality from gallbladder gangrene and perforation.
Men are affected twice as commonly as women (reverse is true in most cases of acute cholecystitis).
The majority of patients are between 50 and 70 years of age and have underlying diabetes mellitus.
Clinical manifestation is often insidious and may then progress rapidly. Up to one-third of patients may be afebrile and localized tenderness is often not a dominant clinical feature.
Vascular compromise of the cystic artery is thought to play a significant role in causing emphysematous cholecystitis. It is associated with acalculous cholecystitis (present in ~50% of cases ) and carries a higher incidence of gallbladder perforation. Commonly isolated organisms include Clostridium welchii / perfringens, Escherichia coli and Bacteroides fragilis .
On imaging, the condition is diagnosed when there is radiographic demonstration of air in the gallbladder wall +/- biliary ducts, in the absence of an abnormal communication with the gastrointestinal tract .
Ultrasonography may demonstrate highly echogenic reflectors with low-level posterior shadowing and reverberation artifact ("dirty" shadowing and "ring-down" artifact) .
A less common but more specific finding is small, non-shadowing echogenic foci rising up from the dependent portions of the gallbladder lumen, similar to effervescing bubbles in a glass of champagne (champagne sign). One reference states that this sign is pathognomonic for gas in the gallbladder .
CT is considered the most sensitive and specific imaging modality for identifying gas within the gallbladder lumen or wall . The presence of a pneumoperitoneum indicates perforation.
Because there is usually cystic duct obstruction, gas is present in the bile ducts in only 20% of cases
Hepatobiliary nuclear imaging may demonstrate non-visualization of the gallbladder, along with a region of increased hepatic activity adjacent to the gallbladder fossa. This feature is sometimes termed the rim sign .
Treatment and prognosis
Treatment is emergent surgical intervention. Overall mortality rate is ~20% (range 15-25%), compared with <5% in uncomplicated cases of acute cholecystitis. Percutaneous cholecystostomy tube placement may be an option for patients who are too unwell for surgery .
History and etymology
It was initially described by C F Hegner in 1931 .
- if in doubt of the diagnosis on ultrasound, obtain a CT to confirm the diagnosis