Emphysematous cholecystitis is a rare (1-3%) but serious and potentially life-threatening form of acute cholecystitis characterized by the presence of gas in the gallbladder wall and/or lumen. Gas-forming bacteria (Clostridium perfringens, Clostridium welchii, Escherichia coli, Klebsiella pneumoniae) multiply in the setting of ischemic necrosis of the gallbladder wall and produce gas in situ. Significantly more common in diabetic men (male:female ratio 3:1, 50% of patients are diabetic). Unlike classic acute cholecystitis, gallstones are absent in 30-50% of cases (acalculous form). Risk of progression to gangrenous cholecystitis is 75%, perforation risk is 20%. Mortality rate is 15-25%, far exceeding classic acute cholecystitis (<1%). Gas detection in the gallbladder wall or lumen on CT is pathognomonic. Emergent cholecystectomy forms the basis of treatment.
Age Range
45-85
Peak Age
65
Gender
Male predominant
Prevalence
Rare
The pathogenesis of emphysematous cholecystitis occurs in three stages. In the first stage, ischemic necrosis develops in the gallbladder wall due to thrombotic occlusion of the cystic artery or atherosclerotic disease — microangiopathy and atherosclerosis in diabetic patients accelerate this process. In the second stage, necrotic tissue creates an ideal growth medium for anaerobic and facultative aerobic bacteria. Gas-forming bacteria, primarily Clostridium perfringens, produce H2, CO2, and N2 gases through carbohydrate fermentation — these gases accumulate within necrotic tissue and appear as intramural gas on CT. In the third stage, bacterial proliferation and gas production further disrupt wall integrity; transmural necrosis develops and perforation risk increases. Diabetes is the most important factor increasing gallbladder wall susceptibility to ischemia: hyperglycemia → endothelial dysfunction → microvascular thrombosis → wall ischemia chain. In the acalculous form (30-50%), cystic artery occlusion alone is sufficient — stone-related obstruction is not needed. Gas first accumulates in the intramural layer (Stage 1), then spreads into the lumen (Stage 2), finally reaches pericholecystic tissue (Stage 3 — perforation). Gas migration to the portal venous system is rare but significantly increases mortality.
Curvilinear or bubbly pattern intramural gas densities in the gallbladder wall — pathognomonic for emphysematous cholecystitis. Staging: Stage 1 (intramural gas), Stage 2 (+ intraluminal gas), Stage 3 (+ pericholecystic gas = perforation).
Curvilinear or bubbly pattern gas densities (-1000 HU) in the gallbladder wall on non-contrast CT. Gas accumulates within the muscularis layer or submucosal/subserosal layer and appears as thin linear or small bubbles following the wall contour. Intramural gas is the earliest and most specific CT finding of emphysematous cholecystitis (Stage 1). Seen together with wall thickening and pericholecystic fluid. Lung window (W1500/L-500) facilitates detection of small gas foci.
Report Sentence
Curvilinear intramural gas densities are observed in the gallbladder wall, consistent with emphysematous cholecystitis; emergent surgical evaluation is recommended.
Gas accumulation in the gallbladder lumen can create an air-fluid level. This indicates Stage 2 emphysematous cholecystitis — gas has spread from the intramural area into the lumen. On supine CT, gas collects in the anterior (non-dependent) part of the gallbladder lumen and bile/purulent fluid remains posteriorly. Intraluminal gas alone is not specific for emphysematous cholecystitis — biliary-enteric fistula, post-ERCP sphincterotomy, enterocholecystic fistula can also cause intraluminal gas; clinical context is distinguishing.
Report Sentence
Gas accumulation creating an air-fluid level is observed in the gallbladder lumen, consistent with advanced stage (Stage 2) emphysematous cholecystitis together with intramural gas findings.
Irregular wall thickening (>3 mm) and heterogeneous/decreased enhancement of the gallbladder wall. Loss of enhancement (non-enhancement) in ischemic necrosis areas while enhancement continues in viable tissue — this 'patchy' pattern suggests gangrenous transformation. Intramural gas foci may be seen together with enhancement defects. Irregular wall thickening and disruption of mucosal enhancement herald transmural necrosis.
Report Sentence
Irregular wall thickening with heterogeneous enhancement and focal non-enhancement areas are observed in the gallbladder wall, consistent with gangrenous emphysematous cholecystitis together with intramural gas findings.
Presence of gas in the pericholecystic area surrounding the gallbladder. This finding indicates Stage 3 emphysematous cholecystitis and suggests perforation — gas has spread from the wall defect to the pericholecystic area. Pericholecystic gas may extend along the hepatoduodenal ligament or toward the liver bed. Concurrent pericholecystic fluid/abscess collection frequently accompanies. Free peritoneal air if present suggests Type I (free) perforation.
Report Sentence
Pericholecystic gas is observed surrounding the gallbladder, consistent with perforated emphysematous cholecystitis (Stage 3) together with intramural gas findings; emergent surgical intervention is indicated.
High-amplitude hyperechoic foci with 'dirty shadowing' and reverberation artifacts in the gallbladder wall or lumen on ultrasound. Gas is the strongest reflector in US and creates posterior shadowing with reverberation lines (ring-down artifact, comet-tail artifact). However, intramural gas must be distinguished from luminal gas. 'Effervescent gallbladder sign' — dynamic gas bubbles on the non-dependent surface — is a diagnostic clue. US sensitivity is lower than CT (50% vs 95%).
Report Sentence
Hyperechoic foci with dirty shadowing artifact and reverberation are observed in the gallbladder wall/lumen, consistent with intramural/intraluminal gas; emphysematous cholecystitis is the leading differential and CT is recommended for confirmation.
Pericholecystic fluid and increased density (stranding) in hepatoduodenal ligament/perihepatic fat tissue surrounding the gallbladder. Indicates that acute inflammation has reached the peritoneal surface. Pericholecystic abscess formation may be seen in complicated cases — thick-walled, rim-enhancing collection. Amount and distribution of pericholecystic fluid assist in predicting complication risk — widespread perihepatic fluid favors perforation.
Report Sentence
Pericholecystic fluid collection and inflammatory stranding in surrounding fat tissues are observed around the gallbladder, supporting findings of complicated cholecystitis.
Criteria
Gas is only accumulated in the gallbladder wall (intramural layer). No gas in the lumen or pericholecystic area. Earliest stage with better prognosis when diagnosed and treated early.
Distinct Features
Thin curvilinear gas following the gallbladder wall contour on CT. Seen together with wall thickening and pericholecystic fluid. Emergent cholecystectomy indicated but mortality lower than Stage 3.
Criteria
Gas accumulation in the gallbladder lumen in addition to intramural gas. Air-fluid level may be visible. Gas has spread from wall defects into the lumen. Gangrenous transformation frequently accompanies.
Distinct Features
Air-fluid level formation, more pronounced disruption of wall enhancement. Gangrenous cholecystitis risk increased (75%). Emergent surgical intervention mandatory.
Criteria
Gas in the pericholecystic area in addition to intramural and intraluminal gas. Gas has spread to pericholecystic tissue through wall defect — perforation present. Most severe stage with highest mortality.
Distinct Features
High risk of pericholecystic abscess, biliary peritonitis. Mortality rises to 25%. Gas spread along hepatoduodenal ligament, gas in liver bed may be visible. Portal venous gas rare but further increases mortality.
Distinguishing Feature
In classic acute cholecystitis, there is NO gas in the gallbladder wall or lumen. Wall thickening, pericholecystic fluid, and Murphy's sign are present but gas finding is the pathognomonic criterion distinguishing emphysematous from classic form. Mortality is <1% in classic form vs 15-25% in emphysematous form.
Distinguishing Feature
In gallbladder perforation, wall defect ('hole sign') and connection of pericholecystic collection with the defect are diagnostic findings; however intramural gas is usually absent. In emphysematous cholecystitis, gas finding is predominant and diagnosis is made in pre-perforation stages.
Distinguishing Feature
In porcelain gallbladder, wall calcification (high density, +100-300 HU) is observed — density difference with gas (-1000 HU) is dramatic. Calcification indicates chronic process; gas in emphysematous cholecystitis indicates acute infectious process.
Distinguishing Feature
In xanthogranulomatous cholecystitis, intramural hypodense nodules (xanthoma granulomas) and wall thickening predominate; no gas. Chronic inflammatory process that can mimic gallbladder carcinoma. In emphysematous cholecystitis, gas is pathognomonic.
Urgency
emergentManagement
surgicalBiopsy
Not NeededFollow-up
no-follow-upEmphysematous cholecystitis is a surgical emergency and emergent cholecystectomy should be planned as soon as diagnosis is made. Mortality rate is 15-25%, far exceeding classic acute cholecystitis (<1%). Gangrenous transformation risk is 75%, perforation risk is 20%. Preoperative broad-spectrum antibiotics (including anaerobic coverage — metronidazole + piperacillin-tazobactam or carbapenem), hemodynamic stabilization, and diabetes control are critical. Percutaneous cholecystostomy (PCC) may be applied as bridge therapy for patients unfit for surgery. Postoperative wound infection and sepsis risk is high in diabetic patients. Mortality increases further with portal venous gas and multidisciplinary approach (general surgery, intensive care, infectious diseases) is mandatory.
Emphysematous cholecystitis is a high-mortality condition requiring emergency surgery (15-25% mortality). Risk of gangrenous change and perforation is high. Particularly common in diabetic and immunosuppressed patients. Early cholecystectomy or percutaneous drainage should be performed.