Acute cholecystitis refers to the acute inflammation of the gallbladder, which is typically due to cystic duct obstruction by a gallstone (acute calculous cholecystitis). Acalculous cholecystitis is less common and is seen predominantly in critically ill patients. RUQ pain, a positive Murphy sign, and fever are the characteristic clinical features of acute cholecystitis. RUQ ultrasound is the preferred initial imaging modality, which would show gallbladder distension, edema, and pericholecystic fluid. Empiric antibiotic therapy and laparoscopic cholecystectomy are the mainstays of treatment. Laparoscopic cholecystectomy should be performed as soon as possible, preferably within 72 hours of admission, unless operative and anesthesia risks outweigh the benefits of urgent surgery. In high-risk patients with severe cholecystitis, a temporizing gallbladder drainage procedure (e.g., percutaneous cholecystostomy, endoscopic gallbladder stenting) should be performed and elective interval cholecystectomy scheduled after the resolution of acute symptoms. Complications of acute cholecystitis include gangrenous cholecystitis, emphysematous cholecystitis, gallbladder perforation, biliary-enteric fistula, gallstone ileus, and pyogenic liver abscess. Chronic cholecystitis may result from recurrent attacks of acute cholecystitis or due to chronic cholelithiasis. Chronic gallbladder inflammation increases the risk of gallbladder carcinoma.
Acute calculous cholecystitis: most common form 
- Cause: obstructing cholelithiasis
- Cholelithiasis → passage of gallstones into the cystic duct → cystic duct obstruction → distention and inflammation of the gallbladder
- Secondary bacterial infection may also be present (E. coli, Klebsiella, Enterobacter, Enterococcus spp. most common) but is not necessary for the development of cholecystitis.
Acalculous cholecystitis: 5–10% of acute cholecystitis 
- See ”Acalculous cholecystitis” in “Subtypes and variants” section
- Right upper quadrant pain
- Positive Murphy sign: sudden pausing during inspiration upon deep palpation of the RUQ due to pain
- Fever, malaise, anorexia
- Nausea and vomiting
Subtypes and variants
Acute acalculous cholecystitis 
- Description: : an acute life-threatening necroinflammatory disorder of the gallbladder, usually seen in critically ill patients, that is not associated with gallstones
- Incidence: 5–10% of acute cholecystitis 
- Etiology: conditions predisposing to bile stasis and reduced perfusion of the gallbladder
- Clinical features: : similar to acute calculous cholecystitis
- Laboratory studies and findings: similar to acute calculous cholecystitis
- Imaging 
- Abdominal ultrasound: preferred initial imaging modality 
- HIDA scan: preferred confirmatory imaging modality if ultrasound is inconclusive 
- CT abdomen with IV contrast: an alternative to HIDA in patients with inconclusive ultrasound findings
- Supportive findings: similar to those on ultrasound
- Initial supportive management: NPO, IV fluids, analgesics (see ''Treatment'' in ''Acute calculous cholecystitis” for details)
- IV antibiotics: see “Empiric antibiotic therapy for acute biliary infection”
- Source control
Emphysematous cholecystitis (EC) 
- Description: : a rare but life-threatening form of acute cholecystitis characterized by air within the gallbladder wall that is caused by gas-forming bacteria (e.g., Clostridium spp., E.coli)
- Epidemiology: : rare; most commonly seen in elderly diabetic men (esp. 50–70 years of age) 
- Clinical features 
- Laboratory studies and findings: similar to those of acute calculous cholecystitis
- Imaging: The characteristic feature of EC on imaging is air within the gallbladder wall or lumen. 
- RUQ ultrasound : hyperechoic air shadows within the gallbladder wall, and within bile in the gallbladder lumen 
- Noncontrast CT abdomen : radiolucent shadows within the gallbladder wall, within bile, and within pericholecystic fluid 
- MRI abdomen : hypointense (signal void) areas within the gallbladder wall
- Abdominal x-ray : radiolucent rim outlining the gallbladder (pear-shaped radiolucency)
- Initial supportive management: NPO, IV fluids, analgesics (see ''Treatment'' section)
- Broad-spectrum IV antibiotics with anaerobic coverage: See Grade III community-acquired infection in “ .”
- Emergency source control procedure
- Initial evaluation: laboratory studies and RUQ ultrasound (consider if available)
- If ultrasound findings are inconclusive, consider HIDA scan, abdominal MRI, or abdominal CT to confirm the diagnosis.
- Assess for choledocholithiasis (see “ ”).
- Once the diagnosis is confirmed, determine the severity (see “Severity grading of acute cholecystitis”).
|Diagnostic criteria for acute cholecystitis |
|Local signs of inflammation|
|Systemic signs of inflammation|
|Imaging findings|| |
Laboratory studies 
Tests to support the clinical diagnosis
- CBC: Leukocytosis is most common, but WBC count may be normal in up to 40% of patients. 
- CRP: elevated
- Blood cultures: should be obtained, especially in patients with grade III acute cholecystitis (see “ ”) 
- Bile cultures: should be obtained in patients undergoing laparoscopic cholecystectomy or gallbladder drainage 
- Tests to assess the severity of disease (see “Severity grading of acute cholecystitis”)
Tests to rule out related biliary comorbidities: should be obtained in all patients with suspected cholecystitis
- LFTs 
- Lipase, amylase
- Tests to rule out differential diagnoses: See “Diagnostic workup of acute abdominal pain.”
RUQ transabdominal ultrasound
See also “Biliary point-of-care ultrasound.”
- Indications: preferred initial imaging modality in suspected acute cholecystitis 
Characteristic findings 
- Gallbladder wall thickening > 3–5 mm 
- Gallbladder distention (8–10 x 4 cm) 
- Gallbladder wall edema (double-wall sign): The innermost and outermost layers appear hyperechoic; edematous tissue appears as a hypoechoic layer in between.
- Sonographic Murphy sign: Tenderness upon compression of the gallbladder with the ultrasound transducer
- Pericholecystic free fluid
- Presence of gallstones and/or biliary sludge (see “Cholelithiasis” for details)
- In emphysematous cholecystitis, mural air appears as hyperechoic shadows within the gallbladder wall. 
- Important consideration: The CBD should be assessed for choledocholithiasis (see '' ” for further details).
- Indications: : preferred confirmatory test for suspected uncomplicated acute cholecystitis if ultrasound findings are inconclusive 
- Procedure: The radioactive tracer 99mTc-hepatic iminodiacetic acid is injected intravenously → selective uptake by hepatocytes → subsequent excretion into bile → bile with radiotracer enters the gallbladder if the cystic duct is patent → visualization of tracer within the gallbladder via a gamma camera 
- Cannot identify complications of acute cholecystitis, if present
- Cannot be used to evaluate for potential differential diagnoses
- May not be widely available
- Characteristic findings
MRI abdomen without and with IV contrast 
- Alternative to CT or HIDA scan in suspected acute cholecystitis with inconclusive ultrasound findings
- Either of the following in patients with contraindications to CT: 
- Suspected choledocholithiasis (MRCP) 
Characteristic findings: Similar to ultrasound findings
- Hyperintensity (T2) of the gallbladder wall and pericholecystic region, indicating inflammation
- Evidence of choledocholithiasis, if present (see ''Diagnosis of choledocholithiasis” for further details)
- Evidence of complications, such as emphysematous cholecystitis, empyema gallbladder, and gallbladder perforation (see ''Complications'' section)
CT abdomen with IV contrast 
- Characteristic findings: similar to those on ultrasound and MRI
- See “Differential diagnosis of acute abdominal pain.”
- See “Overview of biliary disease.”
- RUQ pain with fever
- RUQ pain without fever
The differential diagnoses listed here are not exhaustive.
|Severity grading of acute cholecystitis |
|Grades of severity||Grading criteria|
(Mild acute cholecystitis)
(Moderate acute cholecystitis)
(Severe acute cholecystitis)
Initial management 
- Screen patients for shock. or
- Provide IV fluid resuscitation) and respiratory support (e.g., oxygen therapy) if necessary. (e.g.,
- Start .
- Provide : e.g., analgesia, antiemetics, electrolyte repletion, consider NG tube insertion.
- Maintain NPO status.
- Consult general surgery to determine:
- Identify and treat concurrent choledocholithiasis (see “ ”).
- Monitoring and reevaluation
- Adjust monitoring level to individual patient needs.
- If there is early deterioration, perform
- Consider the development of complications (e.g., ) or other differential diagnoses (e.g., ).
- Consider ICU consult.
Definitive management 
The initial procedure and duration of antibiotic therapy depend on , patient's individual surgical risk, and presence of complications.
- Laparoscopic cholecystectomy
Gallbladder drainage procedures (e.g., percutaneous cholecystostomy) typically performed as a temporizing measure for:
- Unstable or clinically deteriorating patients: e.g., grade II–III acute cholecystitis 
- Frail patients or those at high risk of surgical complications
- Consider prolonging the duration of therapy (beyond the standard recommendation) in patients with:
- Tailor agent to bile and/or blood cultures as soon as available.
Perform preoperative or postoperative stone extraction in patients with concurrent choledocholithiasis.
Low surgical risk
- Postoperative antibiotics not required
- High surgical risk
- Improvement with initial management
- Deterioration despite initial management
- Low surgical risk
- High surgical risk
- Indication: gold standard of treatment for acute calculous cholecystitis 
Timing: depends on surgical and anesthesia risks, disease severity, and symptom duration
Early laparoscopic cholecystectomy: performed within 10 days of symptom onset; preferably within the initial 24–72 hours 
- Indication: symptom duration of ≤ 10 days in patients with low surgical and anesthesia risk(s) 
- High surgical or anesthesia risks
- Symptom duration > 10 days
Interval laparoscopic cholecystectomy (delayed lap. chole)
- Performed 45 days after resolution of symptoms 
- High surgical or anesthesia risk
- Symptom duration > 10 days
- Early laparoscopic cholecystectomy: performed within 10 days of symptom onset; preferably within the initial 24–72 hours 
- Indication: temporizing, minimally invasive measures in high surgical-risk patients not responding to conservative management 
- Contraindication: uncontrolled bleeding diathesis
- Percutaneous cholecystostomy: image-guided placement of a catheter (cholecystostomy tube) into the gallbladder under local anesthesia through the abdominal wall to provide biliary drainage 
- Endoscopic gallbladder stenting: may be preferred over percutaneous cholecystostomy if endoscopy operator expertise is available as it is less invasive. 
All patients with acute cholecystitis require inpatient management.
- Grade I acute cholecystitis: healthcare facility with the ability to perform laparoscopic cholecystectomy
- Grade II acute cholecystitis: advanced healthcare facility with access to urgent gallbladder drainage and surgical expertise to handle a difficult laparoscopic cholecystectomy.
- Grade III acute cholecystitis: same as for grade II PLUS access to intensive care.
Antibiotic therapy for acute biliary infection
General principles 
- Obtain blood cultures prior to administering antibiotics, especially in patients with severe biliary infection.
- Obtain bile cultures at the beginning of any drainage procedure.
- Tailor antibiotic therapy to sensitivity reports as early as possible. 
- Switch to oral antibiotics, if feasible, once improvement is evident. 
- Gram-negative coverage: Escherichia coli (most common), Klebsiella spp., Enterobacter spp., Pseudomonas spp.
- Anaerobic coverage is recommended if biliary-enteric anastomosis is suspected or identified.
- Consider Enterococcus spp. coverage in grade III community-acquired and healthcare-associated infection.
- Choice of empiric antibiotic: should be determined by the following parameters
Timing of antibiotic administration
- Septic shock: within one hour of presentation
- Other patients: within six hours of presentation
Duration of therapy
- Grade I acute cholecystitis, grade II acute cholecystitis: up to 24 hours after early lap. chole.
- Grade III acute cholecystitis and all grades of community-acquired acute cholangitis: 4–7 days after early lap. chole or until symptomatic improvement (if patient is managed conservatively).
- For patients who undergo urgent gallbladder drainage: continue antibiotics for a total of 7 days. 
- All grades of healthcare-associated cholangitis and cholecystitis with gram-positive bacteremia known to cause infective endocarditis : consider 14 days of treatment.
Recommended empiric regimen 
|Empiric antibiotic therapy for acute biliary infection|
|Class of infection||Severity of infection|| |
Suggested single-agent empiric regimen
Suggested combination empiric regimen
|Community-acquired biliary infection|| |
Healthcare-associated biliary infection
|Suspected multi-drug resistant organism infection|
- Establish IV access with two large-bore peripheral IV lines.
- Obtain blood cultures (2 sets), CBC, BMP, coagulation profile, liver chemistries, lipase, amylase, and blood gas
- Arrange RUQ ultrasound or perform if available
- Keep patient NPO
- Administer .
- Identify and immediately treat sepsis if present: e.g., immediate hemodynamic support, antibiotics within the first hour of presentation
- Determine the .
- Provide analgesia, IV fluids, antiemetics, e.g.,
- Consider NG tube for intractable vomiting
- Evaluate and treat concurrent choledocholithiasis (see “Predictors of choledocholithiasis”).
- Consult general surgery for consideration of cholecystectomy or urgent gallbladder drainage.
- Perform serial abdominal examinations.
- Transfer to ICU if the patient has sepsis or shock.
Gangrenous cholecystitis 
- Definition: ischemic necrosis of the gallbladder
- Etiology: most common complication of acute cholecystitis 
- Clinical features: difficult to distinguish from uncomplicated acute cholecystitis
- Treatment: emergency laparoscopic cholecystectomy and empiric antibiotic therapy for biliary infection
Gallbladder perforation 
- Definition: break in the continuity of the gallbladder wall, typically as a consequence of ischemic necrosis
- Clinical features: variable; symptoms typically progress rapidly
- Imaging : focal defect in the gallbladder wall; extraluminal stone may be visualized
- Treatment: emergency laparoscopic cholecystectomy and empiric antibiotic therapy for biliary infection
- See “Cholecystoenteric fistula” in “FIstula.”
Gallbladder empyema (suppurative cholecystitis) 
- Definition: distended pus-filled gallbladder
- Clinical features: similar to uncomplicated acute cholecystitis
- Imaging: gallbladder distention with hyperechoic (on ultrasound) or hyperintense (on CT abdomen with IV contrast) material within its lumen
- Treatment 
- Etiology: may also result from a perforated duodenal or gastric ulcer
- Clinical features
- Diagnostics: well-demarcated, subhepatic, nonhomogeneous fluid-density mass which may contain gas
Chronic cholecystitis 
- Definition: chronic inflammation of the gallbladder
- Clinical features: recurrent symptoms similar to acute cholecystitis but typically less severe and often self-limiting
- Laboratory studies: may be normal 
- Ultrasound abdomen or CT abdomen with IV contrast:
- HIDA scan: delayed visualization of the gallbladder 
- All patients should also be evaluated for choledocholithiasis before treatment (see ''Imaging'' in “Choledocholithiasis”).
- Treatment: elective laparoscopic cholecystectomy 
Porcelain gallbladder 
- Definition: calcification of the gallbladder wall due to chronic inflammation
- Imaging (x-ray or noncontrast CT abdomen): focal or diffuse hyperdensity (radiopaque appearance) of the gallbladder wall
- Clinical significance: a risk factor for gallbladder cancer 
- Treatment: laparoscopic cholecystectomy even if asymptomatic
- Gallbladder cancer 
- Cholecystoenetric fistula and gallstone ileus
- Porcelain gallbladder 
We list the most important complications. The selection is not exhaustive.