Pathophysiology & Etiology - Gallbladder's Grudge
- Calculous Cholecystitis (>90%): A gallstone obstructs the cystic duct, leading to inflammation. This is the most common cause.
- Acalculous Cholecystitis (5-10%): Gallbladder inflammation without stones. Associated with biliary stasis in critically ill patients (e.g., sepsis, TPN, major trauma).
⭐ Acalculous cholecystitis carries a higher risk of gangrene, perforation, and mortality compared to calculous cholecystitis.
Clinical Presentation - Biliary Bellyache
- Location: RUQ or epigastric pain; constant & severe.
- Radiation: Right shoulder or scapula (Boas' sign).
- Onset: Often postprandial, especially after fatty meals.
- Associated: Fever, nausea, vomiting, anorexia.
Physical Exam:
- Positive Murphy's Sign: Inspiratory arrest on deep RUQ palpation.
- Fever (usually low-grade).
- Palpable, tender gallbladder in ~33% of cases.

⭐ Acalculous cholecystitis presents with similar signs but in critically ill patients (e.g., on TPN, post-op, trauma).
Diagnosis - Catching the Culprit
-
Initial Labs:
- CBC: Leukocytosis with a left shift (↑ WBC).
- LFTs: May show ↑ Alk Phos, ↑ Bilirubin.
- Amylase/Lipase: To rule out pancreatitis.
-
Imaging Gold Standard:
- First & Best Test: Right Upper Quadrant (RUQ) Ultrasound.
- Findings: Gallbladder wall thickening (>3 mm), pericholecystic fluid, gallstones, sonographic Murphy's sign.
- Most Accurate Test: HIDA (Hepatobiliary Iminodiacetic Acid) Scan.
- Indicated if ultrasound is equivocal.
- Positive test: Non-visualization of the gallbladder.
- First & Best Test: Right Upper Quadrant (RUQ) Ultrasound.

⭐ Acalculous Cholecystitis: Suspect in critically ill patients (e.g., prolonged TPN, trauma, burns) with unexplained fever and RUQ pain. Diagnosis often requires HIDA scan as ultrasound may be non-specific.
Management - Gallbladder's Eviction
- Initial Stabilization: NPO, IV fluids, analgesia, and IV antibiotics (e.g., Ceftriaxone + Metronidazole) to cover gram-negatives and anaerobes.
- Definitive Treatment: Laparoscopic cholecystectomy is the gold standard.
⭐ Early cholecystectomy (within 72 hours of symptom onset) is crucial. It leads to shorter hospital stays and reduced risk of complications compared to delayed surgery.
Complications - When Things Go South
- Gangrenous Cholecystitis: Most common severe complication, especially in elderly or diabetic patients. Features necrosis and ischemia of the gallbladder wall.
- Perforation: May be localized (forming a pericholecystic abscess) or free, leading to generalized peritonitis.
- Emphysematous Cholecystitis: A surgical emergency caused by gas-forming organisms (e.g., Clostridium). More common in diabetic men; carries high mortality.
- Cholecystoenteric Fistula: An abnormal connection to the bowel.

⭐ Gallstone Ileus: A classic complication where a large stone passes through a fistula and obstructs the ileocecal valve, causing Rigler's triad: pneumobilia, small bowel obstruction, and an ectopic gallstone.
High‑Yield Points - ⚡ Biggest Takeaways
- Acute cholecystitis is most commonly caused by a gallstone obstructing the cystic duct.
- Classic presentation includes RUQ pain (often radiating to the right scapula), fever, and a positive Murphy's sign.
- The best initial diagnostic test is an ultrasound; the most accurate is a HIDA scan.
- Expect leukocytosis with a left shift; serum aminotransferases and amylase can be mildly elevated.
- Treatment is supportive care followed by laparoscopic cholecystectomy.
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