Gangrenous Cholecystitis

Gangrenous cholecystitis is acute cholecystitis with transmural necrosis of the gallbladder wall caused by ischaemia from raised intraluminal pressure and vascular compromise. It carries a high risk of perforation, abscess and bile peritonitis.

It occurs in 2% to 30% of acute cholecystitis, with higher rates in men, patients over 50 to 60 years, diabetes, cardiovascular disease and delayed presentation over 72 hours. Perforation affects about 10% to 15%, and mortality is 4% to 20%, depending on age and comorbidity.

Predictors are leucocytosis over 17 x 10^9/L, heart rate over 100/min, temperature over 38 C, a thick gallbladder wall and diabetes.

Pathophysiology.

Cystic duct obstruction raises gallbladder pressure, reducing venous and arterial flow. Inflammation and bacterial invasion lead to necrosis, usually in the fundus, where the blood supply is poorest.

Persistent right upper quadrant pain, fever, nausea, vomiting, tachycardia and a positive Murphy sign (which may be absent in diabetes and older adults). Peritonitis, rigors and shock suggest perforation.

Red flags.

• Peritonitis.
• Sepsis or shock.
• Leucocytosis over 17 x 10^9/L.
• Pain lasting over 72 hours.

Ultrasound shows gallstones with thickened, asymmetric or irregular wall, intraluminal membranes, pericholecystic fluid and absent mural blood flow. CT shows non-enhancing wall segments, gas, abscess and perforation. Send full blood count, C-reactive protein, lactate, liver tests, lipase and blood cultures.

Differential diagnosis.

• Uncomplicated acute cholecystitis.
• Emphysematous cholecystitis.
• Perforated peptic ulcer.
• Acute pancreatitis.
• Liver abscess.
• Acute cholangitis.

Give antibiotics and perform early cholecystectomy, which is laparoscopic where safe, with a low threshold for subtotal cholecystectomy or conversion. Percutaneous cholecystostomy is used in patients unfit for surgery, but may not drain a necrotic gallbladder adequately.

• Piperacillin-tazobactam: 4.5 g IV every 6 hours for 4 to 7 days after source control; maximum 18 g daily; monitor renal function, blood counts and cultures; reduce for creatinine clearance under 40 mL/min.
• Ceftriaxone with metronidazole (alternative): ceftriaxone 2 g IV once daily plus metronidazole 500 mg IV or orally every 8 hours for 4 to 7 days after source control; maximum ceftriaxone 4 g daily and metronidazole 1.5 g daily; monitor rash, blood counts and neuropathy; reduce metronidazole to 500 mg every 12 hours in severe hepatic impairment.

Perforation with bile peritonitis needs emergency surgery, washout and drainage.

Monitoring. Vital signs, lactate and inflammatory markers daily until settled.

Referral and escalation. General or hepatobiliary surgery urgently; critical care for sepsis.

Special groups. Patients with diabetes and older adults can have subtle signs despite necrosis.