Gallbladder perforation is a serious complication of acute cholecystitis characterized by transmural defect formation in the gallbladder wall. It develops in 2-11% of cases and carries significant morbidity/mortality. According to Niemeier classification, three types exist: Type I (acute/free) free perforation into peritoneal cavity — biliary peritonitis with high mortality (30%), Type II (subacute) contained perforation with pericholecystic abscess/collection — most common type (50%), Type III (chronic) cholecystoenteric fistula formation — risk of gallstone passage into bowel and gallstone ileus. CT is the gold standard for diagnosis — wall continuity disruption (hole sign), pericholecystic fluid/abscess collection, free intraperitoneal fluid, and defect localization are diagnostically critical findings. Perforation usually develops at the fundus because the fundus has the least vascular supply. This is a life-threatening condition requiring emergent surgery.
Age Range
40-85
Peak Age
60
Gender
Equal
Prevalence
Rare
Gallbladder perforation develops through the ischemia-necrosis sequence. After cystic duct obstruction (usually gallstone impaction), increased intraluminal pressure compromises wall vascular perfusion — especially at the fundus, because terminal branches of the cystic artery reach the fundus last with minimal collateral support. Transmural necrosis develops in ischemic wall segments followed by defect formation — this defect appears as focal wall continuity disruption on CT ('hole sign'). In Type I, the defect opens into the free peritoneal cavity — bile fluid is irritant (high bile salt concentration) causing chemical peritonitis, with secondary bacterial infection leading to biliary peritonitis; free intraperitoneal fluid (low HU, bile density) is widely seen on CT. In Type II, the omentum and adjacent organs contain the defect — inflammatory response and fibrin deposition form pericholecystic abscess; thick-walled, rim-enhancing collection connected to the defect is seen on CT. In Type III, chronic inflammation creates a fistula tract to adjacent hollow organ (most commonly duodenum, then hepatic flexure) — gallstone may pass through and stones >2.5 cm may impact at the ileum causing gallstone ileus; Rigler triad (ectopic stone, pneumobilia, small bowel obstruction) is diagnostic on CT.
Focal interruption of the enhancing gallbladder wall on contrast-enhanced CT — the direct imaging finding of the perforation defect. Usually at the fundus and related to pericholecystic collection. The most specific perforation finding. Best detected with thin sections and multiplanar reformations.
CT shows focal wall continuity disruption (hole sign) — the most specific and direct finding of perforation. The defect is usually located at the fundus (60-70%) or body (20-30%). On contrast-enhanced CT, it appears as the point where enhancing wall is focally interrupted — defect size may vary from a few mm to 1-2 cm. Thin-section CT (≤2 mm) and multiplanar reformations are required for defect detection. Wall irregularity, edema, and inflammatory changes surround the defect. Pericholecystic collection is seen in relation to the defect.
Report Sentence
Focal wall continuity disruption (hole sign) at the gallbladder [fundus/body], consistent with gallbladder perforation.
In Type II (subacute) perforation, a thick-walled, rim-enhancing abscess/collection is seen around the gallbladder. The collection is usually adjacent to the defect location and demonstrates extravasation from the gallbladder lumen. Content may be fluid density (0-30 HU), may contain air bubbles (gas-forming organisms), or hemorrhagic component. Collection size varies from a few cm to 10+ cm. The omentum and adjacent organs contain the collection.
Report Sentence
A thick-walled, rim-enhancing pericholecystic collection measuring approximately [x] cm, consistent with Type II (subacute) perforation.
In Type I (acute/free) perforation, free intraperitoneal fluid is widely seen — bile-density fluid (0-20 HU) accumulates in Morrison pouch, pelvis, paracolic gutters, and subphrenic space. Free fluid presence distinguishes free perforation (Type I) from contained perforation (Type II) and indicates more severe presentation (biliary peritonitis). Air bubbles may be seen within fluid. Mesenteric and peritoneal enhancement reflecting peritoneal irritation may be seen on contrast phases.
Report Sentence
Widespread free fluid in the peritoneal cavity, consistent with gallbladder perforation (Type I — free perforation) and biliary peritonitis; emergent surgical consultation recommended.
In Type III (chronic) perforation, Rigler triad: (1) ectopic gallstone — calcified structure in bowel lumen, most commonly terminal ileum; (2) pneumobilia — air in biliary tree; (3) small bowel obstruction — dilated bowel loops proximal to ectopic stone. This triad is pathognomonic for gallstone ileus. The cholecystoenteric fistula may be directly demonstrated on CT as a tract between gallbladder and duodenum/colon. The gallbladder is usually contracted, thickened, and may contain air. Ectopic stone size is usually >2.5 cm.
Report Sentence
Ectopic gallstone (in terminal ileum), pneumobilia, and small bowel obstruction findings (Rigler triad), consistent with cholecystoenteric fistula and gallstone ileus.
US perforation findings: acute cholecystitis findings (thickened wall >4 mm, pericholecystic fluid, impacted stone, positive sonographic Murphy) with added focal wall defect or area of wall contour loss. Pericholecystic collection may be seen in relation to the defect. However, US sensitivity for perforation detection is lower than CT (30-70% vs >90%) — especially when the defect is small or bowel gas obscures imaging. When US suggests complicated cholecystitis, CT confirmation is recommended.
Report Sentence
Suspected wall continuity disruption at the gallbladder fundus with pericholecystic collection overlying acute cholecystitis findings; CT recommended for perforation confirmation.
In perforation cases, pericholecystic fat stranding is prominent and extensive — much wider area involvement is expected compared to uncomplicated cholecystitis. Fat stranding may extend beyond the gallbladder border to the hepatoduodenal ligament, omentum, and adjacent mesocolon/peritoneal surfaces. This extensive inflammatory change reflects perforation severity. Peritoneal enhancement on delayed CT is a finding of inflammatory peritonitis.
Report Sentence
Prominent and extensive pericholecystic fat stranding is noted, favoring complicated cholecystitis/perforation.
Criteria
Wall defect opens into free peritoneal cavity. Free intraperitoneal fluid, biliary peritonitis. Most severe type, 30% mortality. Constitutes 20-30% of cases.
Distinct Features
Widespread ascites, peritoneal enhancement on CT. Acute abdomen presentation. Emergent surgery is definite. Higher risk in immunosuppressed and diabetic patients.
Criteria
Defect is contained by omentum and adjacent organs — pericholecystic abscess/collection forms. Most common type (50%). Mortality lower than Type I (~15%).
Distinct Features
Thick-walled, rim-enhancing collection connected to defect on CT. Initial treatment with percutaneous drainage + antibiotics, followed by delayed cholecystectomy.
Criteria
Chronic inflammation creates fistula tract to adjacent organ — most commonly duodenum (75%), hepatic flexure (15%), stomach (5%). Gallstone may pass into bowel causing gallstone ileus.
Distinct Features
Rigler triad is pathognomonic. Fistula tract, gallbladder air, bowel obstruction on CT. Ectopic stone most commonly impacts at terminal ileum (narrowest lumen). Surgery: enterolithotomy ± cholecystectomy ± fistula repair.
Distinguishing Feature
Uncomplicated acute cholecystitis: wall thickening + pericholecystic fluid but wall continuity is preserved, no hole sign. In perforation, wall defect and abscess/free fluid are added.
Distinguishing Feature
Empyema: purulent material in gallbladder lumen (high density fluid, 20-40 HU), thickened but intact wall. Perforation additionally has wall defect and extraluminal collection.
Distinguishing Feature
Gallbladder carcinoma: asymmetric wall thickening, avid enhancement, liver bed invasion, LAP. Perforation: acute presentation, symmetric thickening, defect + collection, no LAP.
Distinguishing Feature
Xanthogranulomatous cholecystitis: marked wall thickening, intramural nodules, liver bed extension — mimics carcinoma. In perforation, focal defect and extraluminal collection are predominant.
Urgency
emergentManagement
surgicalBiopsy
Not NeededFollow-up
no-follow-upGallbladder perforation is a life-threatening condition requiring emergent surgery. Type I requires emergent cholecystectomy + peritoneal lavage — mortality up to 30%. Type II may have emergent or delayed surgery — percutaneous drainage as bridge therapy. Type III with gallstone ileus requires emergent enterolithotomy + interval cholecystectomy. Early diagnosis significantly reduces mortality — CT sensitivity (>90%) is critical. Risk factors: advanced age, diabetes, immunosuppression, delayed presentation.
Gallbladder perforation is a serious complication requiring emergency surgery. Mortality rate is 10-30%. Type I is the most urgent (biliary peritonitis). Early diagnosis and surgical intervention are life-saving.