Inflammation of the gallbladder, most often from a stone obstructing the cystic duct.
Also known as: acute cholecystitis, cholecystitis, calculous cholecystitis, acalculous cholecystitis
Overview
Acute inflammation of the gallbladder, most commonly caused by cystic duct obstruction by a gallstone (calculous cholecystitis, 90-95%) or, less commonly, in the absence of stones (acalculous cholecystitis, often in critically ill patients).
Epidemiology
Affects ~200,000 patients annually in the US. Female predominance (3:1). Increased risk with age and gallstone prevalence (~10-15% of US adults). Acalculous cholecystitis represents 5-10% of cases and carries higher mortality.
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Question 1GastrointestinalMedium
A 45-year-old woman has a 1-day history of right upper quadrant pain, fever to 38.5°C, and nausea after a fatty meal. On examination she has right upper quadrant tenderness with inspiratory arrest during palpation and no scleral icterus. WBC is 16,000/mm³, and serum lipase is within normal limits. Right upper quadrant ultrasound shows cholelithiasis with gallbladder wall thickening, pericholecystic fluid, and a normal-caliber common bile duct. Which of the following is the most likely diagnosis?
ABiliary colic
BPerforated peptic ulcer
CAcute cholecystitis
DPyogenic liver abscess
Reveal answer & full explanation
Correct answer: C — Acute cholecystitis
ABiliary colic
BPerforated peptic ulcer
CAcute cholecystitis✓
DPyogenic liver abscess
Why Acute cholecystitis is correct
Cholelithiasis with a thickened gallbladder wall and pericholecystic fluid on ultrasound, combined with fever, leukocytosis, and a positive Murphy sign (inspiratory arrest), is the classic picture of acute calculous cholecystitis
The inflamed, obstructed gallbladder produces localized right upper quadrant tenderness without the jaundice or ductal dilation that mark biliary obstruction
Management is intravenous fluids and antibiotics with early laparoscopic cholecystectomy, typically within 72 hours
Why the others are wrong
Biliary colic — Produces transient post-prandial right upper quadrant pain that resolves within hours without fever, leukocytosis, or sonographic wall thickening; choosing it ignores the inflammatory findings (premature closure on the most common cause of gallstone pain)
Perforated peptic ulcer — Causes abrupt diffuse peritonitis with a rigid, board-like abdomen and free intraperitoneal air, not focal inspiratory arrest over a stone-filled gallbladder with pericholecystic fluid (anchoring on acute abdominal pain with leukocytosis)
Pyogenic liver abscess — Also produces fever, right upper quadrant pain, and leukocytosis, but typically follows a subacute illness over weeks and shows a focal hepatic fluid collection rather than gallbladder wall thickening (overreading fever plus leukocytosis as hepatic infection)
Question 2GastrointestinalMedium
A 43-year-old woman has fever, right upper quadrant pain, and vomiting after a fatty meal. The Murphy sign is positive. Which of the following is the most appropriate initial diagnostic study?
ACT of the abdomen and pelvis
BMRCP of the biliary tree
CHepatobiliary iminodiacetic acid scan
DRight upper quadrant ultrasonography
Reveal answer & full explanation
Correct answer: D — Right upper quadrant ultrasonography
ACT of the abdomen and pelvis
BMRCP of the biliary tree
CHepatobiliary iminodiacetic acid scan
DRight upper quadrant ultrasonography✓
Why Right upper quadrant ultrasonography is correct
Right upper quadrant ultrasound is the first-line imaging study for suspected acute cholecystitis.
It detects gallstones, gallbladder wall thickening, pericholecystic fluid, and a sonographic Murphy sign.
Postprandial RUQ pain, fever, and a positive Murphy sign fit acute gallbladder inflammation.
Why the others are wrong
MRCP of the biliary tree — Wrong-indication trap: MRCP is for suspected choledocholithiasis or ductal disease, and this patient has no jaundice or duct dilation to justify it first.
Hepatobiliary iminodiacetic acid scan — Right-disease-wrong-sequence trap: HIDA confirms cystic-duct obstruction but is reserved for equivocal cases after ultrasound.
CT of the abdomen and pelvis — Lower-yield-first-test trap: CT is less sensitive than ultrasound for gallstones and carries radiation, so it is not the initial study.
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Stone impaction in the cystic duct (Hartmann pouch) → gallbladder distension → mucosal injury → secondary bacterial infection (E. coli, Klebsiella, Enterococcus). Progressive ischemia leads to gangrene and perforation if untreated. Acalculous cholecystitis: stasis and ischemia in critical illness drive inflammation without obstruction.
Clinical presentation
Symptoms
Constant, severe RUQ or epigastric pain lasting >6 h (vs <6 h in biliary colic)
Radiation to right shoulder or interscapular area
Nausea and vomiting
Fever and chills
Anorexia
Signs / physical exam
RUQ tenderness with positive Murphy sign (inspiratory arrest on palpation of RUQ during deep inspiration)
Voluntary guarding
Tachycardia, low-grade fever
Palpable distended gallbladder in ~30%
Mild jaundice in ~10% (Mirizzi syndrome — extrinsic CBD compression by stone in cystic duct)
Classic findings
Postprandial RUQ pain lasting >6 h with fever, leukocytosis, and positive Murphy sign.
Differential diagnosis
Biliary colic — Episodic RUQ pain that resolves within hours, no fever, normal labs, no wall thickening on US — same pain mechanism without sustained obstruction
Hepatobiliary iminodiacetic acid (HIDA) scan — most sensitive/specific; non-visualization of gallbladder after 1-4 h confirms cystic duct obstruction; used when ultrasound equivocal
CT abdomen — when alternative diagnoses considered, complications suspected (perforation, emphysematous cholecystitis), or HIDA unavailable
MRCP — when choledocholithiasis suspected
EUS — high-resolution evaluation for CBD stones
Diagnostic algorithm
TG18 Severity Grade
Criteria
Management
Grade I (Mild)
No organ dysfunction, mild local inflammation
Early laparoscopic cholecystectomy
Grade II (Moderate)
WBC >18,000, palpable mass, duration >72 h, marked local inflammation
Early laparoscopic cholecystectomy at center with expertise
Grade III (Severe)
Organ dysfunction (CV, neuro, respiratory, renal, hepatic, hematologic)
Stabilize → percutaneous cholecystostomy or delayed surgery
Tokyo Guidelines (TG18) acute cholecystitis severity grading and management.
Treatment
First-line
NPO, IV fluids, analgesia (NSAIDs and opioids; morphine traditionally avoided over sphincter of Oddi concerns but clinically used)
IV antibiotics — piperacillin-tazobactam, ceftriaxone + metronidazole, or ertapenem (broaden for severity)
Early laparoscopic cholecystectomy — within 72 h preferred; equivalent outcomes to delayed cholecystectomy with shorter total hospitalization (ACDC trial)
Convert to open if anatomy unclear, severe inflammation, or aberrant biliary anatomy suspected
Second-line / adjunct
Percutaneous cholecystostomy tube — for poor surgical candidates (severe sepsis, ICU patients, high comorbidity) with planned interval cholecystectomy or definitive drainage
Endoscopic gallbladder drainage (EUS-guided) — emerging alternative for non-operative candidates
Delayed cholecystectomy 6-8 weeks if patient unable to undergo early surgery and inflammation has cooled
Treat acalculous cholecystitis with percutaneous cholecystostomy in critically ill patients
Complications
Gangrenous cholecystitis
Gallbladder perforation — localized abscess or biliary peritonitis
Empyema of the gallbladder
Emphysematous cholecystitis — gas in gallbladder wall; diabetics; Clostridium perfringens, E. coli; HIGH mortality, requires emergent cholecystectomy or open drainage
Cholecystoenteric fistula — gallstone ileus (stone erodes into duodenum, lodges at ileocecal valve — Rigler triad: pneumobilia, SBO, ectopic stone)
Sepsis, multiorgan failure
Postcholecystectomy syndrome (persistent symptoms post-surgery — sphincter of Oddi dysfunction, retained stones)
PANCE pearls
Early laparoscopic cholecystectomy (<72 h) is preferred over delayed surgery (CHOCOLATE, ACDC trials).
Murphy sign: inspiratory arrest during RUQ palpation. Sonographic Murphy sign is more specific than clinical exam.
HIDA scan is the most accurate test for acute cholecystitis when ultrasound is equivocal — non-filling of the gallbladder at 1-4 h confirms cystic duct obstruction.
Acalculous cholecystitis: think in critically ill, TPN, mechanically ventilated, post-trauma, burn patients — high mortality; cholecystostomy often first-line.
Emphysematous cholecystitis: diabetic patients, gas in gallbladder wall on imaging, polymicrobial including Clostridium; surgical emergency.
Gallstone ileus (Rigler triad): pneumobilia + small bowel obstruction + ectopic gallstone; treat with enterolithotomy ± delayed cholecystectomy.
Mirizzi syndrome: cystic duct stone compressing CBD; preoperative MRCP critical to avoid bile duct injury.
Sickle cell patients with pigment stones — perioperative care includes transfusion to Hgb ~10 to reduce sickling.
Pregnancy: laparoscopic cholecystectomy is safe in 2nd trimester; avoid 1st (teratogenicity) and 3rd (technical difficulty).
References
Tokyo Guidelines TG18 — Yokoe M et al. Tokyo Guidelines 2018: diagnostic criteria and severity grading of acute cholecystitis. J Hepatobiliary Pancreat Sci 2018;25:41-54
CHOCOLATE Trial — Loozen CS et al. Laparoscopic cholecystectomy versus percutaneous catheter drainage for acute cholecystitis in high-risk patients (CHOCOLATE). BMJ 2018;363:k3965
WSES 2020 — Pisano M et al. 2020 WSES guidelines for the detection and management of bile duct injury during cholecystectomy. World J Emerg Surg 2020;15:61
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