Acute Cholecystitis: Symptoms, Causes & Treatment

Acute cholecystitis is acute inflammation of the gallbladder wall. In 90–95% of cases, it is caused by cystic duct obstruction by a gallstone (calculous cholecystitis): bile accumulates, intraluminal pressure rises, venous outflow is compromised, ischemia ensues, and bacterial superinfection (E. coli, Klebsiella, Enterococcus) follows. Acalculous cholecystitis (5–10%) occurs without stones, primarily in critically ill patients after major surgery, severe trauma, or prolonged fasting — from bile stasis and ischemia.

Gallstone disease affects 10–15% of Western adults; approximately 20% of those with gallstones develop acute cholecystitis over their lifetime. Risk factors follow the classic '4 Fs' (Female, Fat, Forty, Fertile) plus additional factors: rapid weight loss, TPN, diabetes, and hemolytic disorders (pigment stones). Acute cholecystitis is one of the most common indications for emergency abdominal surgery worldwide.

The inflammatory process progresses from edema and hyperemia (mild) through empyema (pus in the gallbladder) to gangrene and perforation — each stage increasing procedural difficulty and morbidity. Tokyo Guidelines provide internationally accepted diagnostic criteria (TG18) and severity grading (mild/moderate/severe) to guide timing and type of intervention.

• Severe constant right upper quadrant or epigastric pain, often radiating to the right shoulder or back (diaphragmatic irritation by bile)
• Nausea and vomiting
• Fever (38–39°C) with chills
• Positive Murphy's sign: arrest of inspiration on palpation of the right subcostal area — highly specific for cholecystitis
• RUQ tenderness with guarding; may have palpable tender gallbladder
• Jaundice suggests common bile duct stone (choledocholithiasis) — a separate complication

• Gallstone obstruction of the cystic duct — the primary cause (90–95%)
• Acalculous cholecystitis: bile stasis and ischemia in ICU patients, post-cardiac surgery, TPN, burns, sepsis
• Risk factors for gallstones: female sex, obesity (BMI >30), parity, age >40, rapid weight loss, TPN, ileal disease (Crohn's), hemolytic anemia (sickle cell, hereditary spherocytosis)
• Drugs: ceftriaxone (biliary sludge), fibrates, octreotide

Diagnosis by Tokyo Guidelines TG18 requires: local inflammation signs (Murphy's sign, RUQ tenderness) + systemic inflammation (fever, elevated WBC/CRP) + imaging confirmation. Abdominal ultrasound: first-line — demonstrates gallstones, gallbladder wall thickening (>4 mm), pericholecystic fluid, sonographic Murphy's sign (sensitivity 80–88%, specificity 80–88%). CT abdomen: superior for complications (gangrene, perforation, emphysematous cholecystitis) when ultrasound inconclusive. HIDA scan: most sensitive for diagnosing acute cholecystitis (95%) but slower; reserved for equivocal cases.

Hospital admission: NPO, IV fluids, analgesics (NSAIDs or opioids). Antibiotics: cover gram-negative enteric organisms (E. coli, Klebsiella) and anaerobes — ceftriaxone + metronidazole, or piperacillin-tazobactam for severe cases; 24–48 hours for mild, continued until recovery for severe. Laparoscopic cholecystectomy: definitive treatment — early surgery (within 24–72 hours of admission) preferred over delayed interval surgery for mild-to-moderate cholecystitis (lower conversion rate, shorter hospitalization, no risk of recurrent episodes during waiting). Severe/gangrenous cholecystitis: urgent surgery. Percutaneous cholecystostomy: tube drainage under ultrasound guidance for high-risk surgical patients as bridge to elective cholecystectomy.

• Gangrenous cholecystitis: ischemic necrosis of the gallbladder wall — risk of perforation; requires urgent surgery
• Gallbladder perforation: local (pericholecystic abscess), free perforation (biliary peritonitis), or fistula formation
• Ascending cholangitis from cystic duct obstruction spreading to the bile ducts — requires urgent ERCP
• Gallstone ileus: large stone erodes through the gallbladder wall into the duodenum and obstructs the ileum
• Empyema: pus-filled gallbladder — requires urgent drainage

• Maintain healthy body weight; avoid rapid weight loss (>1 kg/week) which promotes gallstone formation and cholesterol supersaturation
• Healthy diet: reduce saturated fats and refined carbohydrates; increase dietary fiber (reduces enterohepatic cycling and cholesterol secretion)
• Ursodeoxycholic acid prophylaxis during rapid weight loss (bariatric surgery patients)
• Early enteral feeding in ICU patients to prevent acalculous cholecystitis from bile stasis