A stone parks in the plumbing. Where it lands decides everything: the gallbladder neck, the common bile duct, or the ampulla. Read the labs, climb the imaging ladder, and never operate out of order.
A 45-year-old woman with obesity comes in with 12 hours of steady right upper quadrant pain that started after a fatty meal and now wraps around to her right shoulder blade. She is febrile. When you press under her right rib cage and ask her to breathe in, she catches her breath and stops short (positive Murphy sign). Ultrasound shows a thickened gallbladder wall, fluid tracking around the gallbladder, and stones.
What is the most likely diagnosis?
Acute pancreatitis
Acute cholecystitis
Ascending cholangitis
Peptic ulcer disease
Clinical Images
Biliary tree anatomy: cystic duct, CBD, ampulla · tap to expand
Gross gallstones · cholesterol vs pigment · tap to expand
RUQ ultrasound: stone, shadow, wall thickening · tap to expand
The Plumbing
Where the Stone Lands Decides the Disease
Same stone, different real estate. Walk the bile downstream and the syndromes line up one after another.
Follow the bile
The liver makes bile. It drains down the hepatic ducts into the common hepatic duct. A side branch, the cystic duct, fills and empties the gallbladder (the storage tank). Downstream, the common bile duct joins the pancreatic duct at the ampulla of Vater, guarded by the sphincter of Oddi, and dumps into the duodenum. Park a stone at each junction and you get a different disease.
Biliary colic: a stone temporarily plugs the cystic duct after a fatty meal → gallbladder squeezes against a closed door → crampy pain for under an hour → the stone falls back, the door opens, pain resolves. No fever, no inflammation.
Acute cholecystitis: the stone stays wedged in the cystic duct → bile cannot escape → the trapped gallbladder distends, the wall inflames and becomes ischemic → constant pain, fever, positive Murphy sign.
Choledocholithiasis: a stone slips into the common bile duct → bile backs up toward the liver → conjugated (direct) bilirubin and alkaline phosphatase climb → jaundice, dark urine, pale stool, and a dilated duct on ultrasound.
Ascending cholangitis: that obstructed, stagnant bile gets infected → bacteria climb the duct toward the liver → Charcot triad (pain, fever, jaundice) → if pus builds under pressure, sepsis follows (Reynolds pentad).
Gallstone pancreatitis: a stone lodges at the ampulla and blocks the shared pancreatic outflow → pancreatic enzymes back up and autodigest → epigastric pain to the back with a high lipase.
Who grows the stones
Cholesterol stones (the common ones): the 5 F's — sorry, the five risk words: Female, Forty, Fat, Fertile (estrogen, pregnancy), and Fair. Rapid weight loss and fibrates also count.
Black pigment stones: chronic hemolysis (sickle cell, hereditary spherocytosis) floods bile with bilirubin.
Brown pigment stones: biliary infection and stasis, classically in chronically obstructed or infested ducts.
The two that skip the stones
Acalculous cholecystitis: a critically ill patient (ICU, sepsis, major burns, trauma, on TPN, ventilated) gets gallbladder stasis and low blood flow. The wall inflames and necroses with no stone at all. High risk of gangrene because it hides in a sedated patient.
Emphysematous cholecystitis: in diabetics and the vasculopathic, gas-forming bacteria (classically Clostridium, also E. coli) invade an ischemic wall → air appears inside the gallbladder wall. A surgical emergency with a high perforation rate.
🧠Memory hook: walk the stone downstream — "Colic, Cholecystitis, Choledocho, Cholangitis." Each step adds a finding: pain, then fever, then jaundice, then sepsis.🔑Cystic duct = gallbladder problem (pain, Murphy). Common bile duct = jaundice (direct bili, alk phos). Infected duct = cholangitis (Charcot). Ampulla = pancreatitis (lipase).
Read the Pattern
Presentation and the Imaging Ladder
The labs tell you which junction is blocked. The imaging tells you what to do about it.
Murphy sign, explained simply
Lay two fingers under the right costal margin and ask the patient to inhale. The diaphragm pushes the inflamed gallbladder down onto your fingers. It hurts so much the patient stops breathing in mid-breath. That arrest of inspiration is a positive Murphy sign, and the same maneuver done with the ultrasound probe is the sonographic Murphy sign.
Syndrome
Pain
Fever / WBC
Bilirubin and Alk Phos
Key marker
Biliary colic
Under 1 hour, resolves
No
Normal
Stones, normal wall
Acute cholecystitis
Constant, RUQ, to scapula
Yes
Near normal
Positive Murphy, thick wall
Choledocholithiasis
RUQ, with jaundice
Usually no
Direct bili and alk phos up
Dilated common bile duct
Ascending cholangitis
RUQ, with rigors
Yes, high
Both up
Charcot triad, sepsis
Gallstone pancreatitis
Epigastric, to the back
Variable
May be up
Lipase over 3x normal
Right upper quadrant ultrasound (always first)
Cheap, fast, no radiation. Look for stones, a wall over 3 mm, pericholecystic fluid, and a sonographic Murphy sign.
Why first: it answers most cases on its own and needs no contrast or sedation.
HIDA scan (when ultrasound is equivocal)
Cholescintigraphy tracks a tracer from liver to gallbladder. If the gallbladder does not fill, the cystic duct is blocked.
Why: nonvisualization of the gallbladder is the most sensitive and specific sign of acute cholecystitis when the ultrasound is inconclusive.
MRCP (to map the ducts noninvasively)
A magnetic resonance picture of the biliary tree. Purely diagnostic, no instrument enters the patient.
Why: best for intermediate probability of a duct stone, so you do not expose a patient to an invasive procedure they may not need.
ERCP (diagnostic and therapeutic)
A scope cannulates the ampulla. It finds the stone and can cut the sphincter and pull the stone out in the same sitting.
Why: reserve it for high probability or confirmed duct stones and for cholangitis, because it actually treats the obstruction. It is also how you decompress an infected duct.
⚠
Charcot vs Reynolds, do not blur them
Charcot triad = RUQ pain + fever + jaundice = cholangitis. Add hypotension and altered mental status and you have Reynolds pentad = suppurative cholangitis, a patient circling the drain who needs the duct drained now, not in the morning.
⚠
Cystic duct vs common bile duct on the labs
Cystic duct block (cholecystitis) leaves bilirubin near normal because bile still drains through the open common bile duct. The moment bilirubin and alkaline phosphatase jump, the block has moved downstream into the common bile duct. Jaundice means the duct, not just the gallbladder.
Order of Operations
Treat It, In the Right Sequence
The wrong order kills. Clear an infected or obstructed duct before you take the gallbladder.
Stable disease
Biliary colic: reassure, then elective laparoscopic cholecystectomy. No rush, no antibiotics.
Acute cholecystitis: admit, NPO, IV fluids, analgesia, and antibiotics, then early laparoscopic cholecystectomy (ideally within 72 hours).
Choledocholithiasis: clear the duct with ERCP (sphincterotomy and stone extraction), then take the gallbladder. Never leave a ductal stone behind a removed gallbladder.
Emergencies
Ascending cholangitis: IV fluids and broad-spectrum antibiotics plus urgent biliary decompression (ERCP). Antibiotics alone do not relieve the obstruction. Cholecystectomy comes later, once the patient recovers.
Acalculous cholecystitis in the unstable ICU patient: the patient is too sick for the OR, so percutaneous cholecystostomy drains the gallbladder at the bedside. Interval cholecystectomy after recovery.
Emphysematous cholecystitis:emergent cholecystectomy plus broad-spectrum antibiotics that cover Clostridium. Do not wait, the wall is gangrenous.
🎓From the attending: when a septic patient has Charcot turning into Reynolds, your reflex is antibiotics, and antibiotics are necessary. But the bile is trapped under pressure behind a stone. You cannot antibiotic your way through a closed pipe. Drain the duct. That is the move that saves the patient. Every time.
⚠
Never beta the gallbladder, I mean never cut before you decompress
In cholangitis, taking the gallbladder in an unstable septic patient does not fix the obstructed common bile duct and can kill them on the table. Decompress first (ERCP), stabilize, then operate electively. Source control of the infected duct beats heroics in the OR.
One more board favorite
Porcelain gallbladder (a calcified gallbladder wall on imaging) carries a raised risk of gallbladder cancer, so it earns a cholecystectomy even when the patient feels fine. Calcified wall is different from the intramural gas of emphysematous disease, do not confuse the two.
Prove It
Board Walkthrough
Original clinical vignettes. Five dealt per round, answer choices shuffled, never-repeat within a round. Tap a wrong answer first to see why it almost works, then read the glowing clues.
Medically reviewed by Kaitlyn Cocuzzo, MD and Fatima Ali, DO · Last updated July 1, 2026 at 10:03 PM ET
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