EMPHYSEMATOUS CHOLECYSTITIS
INTRODUCTION:
It is an acute infection of gall bladder by gas forming organism.
# In about 1/3 Clostridium perfringes.
# Others are E.coli and Klebsiella.
# Rarely only 1% of all cases of acute cholecystitis.
# Occurs more often in men . ( As opposed to gall bladder disease in general which occurs more often in women ).
# Mostly are elderly patients ( more than 60 years of age ) with diabetes.
# Vascular compromise of the cystic artery may play a role in the etiology. ( Gall stones may be associated with the disease but are not though cause it ).
# Gas may escape into the bile ducts. ( This is rare since cystic duct is occluded in cholecystitis ).
CLINICAL FINDINGS:
1) With cholecystitis right upper quadrant pain is the presenting symptom.
2) Luecocytosis.
3) Jaundice ( rare ).
IMAGING FEATURES:
Conventional Radiography:
May show air in the wall or lumen of gall bladder. Air-fluid levels in the gall bladder are seen with images obtained with a horizontal beam and not on supine radiographs. Gas may spread to the pericholecystic tissues.
USG findings:
Indistinct shadowing emanating from wall or lumen of gall bladder.
"Ring-down effect" or "Comet-tail" from shadowing from air in gall bladder lumen.
CT findings:
1) Air in the gall bladder wall is the diagnostic feature.
2) Most common sign of non-emphysematous cholecystitis are gall bladder thickness more than 3 mm.
3) Cholelithiasis.
4) Increased density of bile ( more than 20 HU )
5) Loss of clear definition of gall bladder wall.
6) Pericholecystic fluid such as halo of edema.
CT is an excellent technique to diagnose emphysematous cholecystitis because it detects and localizes gas easily as a result of its superior contrast and spatial resolution. No intravenous or oral contrast agent is required and unlike on plain film or ultrasound, bowel gas is usually readily differentiated.
TREATMENT:
Definitive treatment is surgical intervention.
Preoperative percutaneous drainage may improve survival.
In some cases emergency cholecystectomy is done. ( Mortality rate is 15-25% ).
COMPLICATION:
Perforation: Five fold increase in perforation over uncomplicated acute cholecystitis. But now frequency is declining because of earlier diagnosis of acute cholecystitis.