Gastrointestinal: Gallbladder Flashcards
When should you consider the gallbladder to be dilated?
> 4 cm in short-axis diameter
Note: The gallbladder can be mildly dilated in a normal fasted pt.
Cutoff for gallbladder wall thickening?
> 3 mm
What are the anatomical sections of the gallbladder?
Arrows
Spiral valves of Heister
Why does the cystic duct appear tortuous in this MRCP?
Spiral valves of Heister (normal anatomy)
Persistent bile leak s/p cholecystectomy…
Think about accessory cystic ducts (ducts of Luschka)
Gallbladder finding
Phrygian cap
Intrahepatic gallbaldder
Variant anatomy where the gallbladder is within the liver (usually right above the interlobular fissure)
CT cholangiogram in a pt with persistent bile leak s/p cholecystectomy…
Think accessory cystic duct (of Luschka)
Note: Extravasated contrast is seen adjacent to the cholecystectomy clips and a small branch of the right hepatic duct is seen (possible accessory duct of Luschka).
Gallstones in a child…
Think sickle cells disease
Note: These are usually cholesterol stone (75%) but can also be pigmented stones (25%).
Why might a gallstone not have posterior shadowing on ultrasound?
- Its not actually a stone
- Its <3 mm
Gallbladder ultrasound
Dirty shadowing from the anterior gallbladder wall, suspicious for emphysematous cholecystitis
Note: Emphysematous cholecystitis is at a high risk of perforation.
What is the most specific ultrasound finding of acute cholecystitis?
Positive sonographic Murphys sign AND cholelithiasis
Negative sonographic Murphys sign
Gangrenous cholecystitis (necrosis of gallbladder)
Note: Sloughed membranes are highly suspicious. Sonographic Murphys sign is often negative (due to necrosis of the nerves).
Emphysematous cholecystitis is most common in what pt population?
Elderly diabetics
Gallbladder wall thickening and pericholecystic fluid in a pt s/o heart valve replacement…
Think acalculus cholecystitis
Gallbladder not visualized on HIDA scintigraphy of a pt in the ICU…
Think acalculus cholecystitis
Mirizzi syndrome
Common hepatic duct obstruction secondary to mass effect from a gallstone in the cystic duct
Note: The impacted stone can eventually erode into the common hepatic duct or GI tract.
Risk factors for Mirizzi syndrome
Low cystic duct insertion
Note: This results in a more parallel course and closer proximity to the common hepatic duct.
Pts with Mirizzi syndrome are at a 5x risk of…
Gallbladder cancer
Bouveret syndrome
Gastric outlet obstruction secondary to a gallstone obstructing the gastric pylorus or proximal duodenum
Note: Bouveret causes belching (from gastric distention). Gallstone ileus is more commonly caused by a gallstone obstructing the ileocecal valve.
What is the difference between gallbladder adenomyomatosis and cholesterolosis?
In gallbladder adenomyomatosus, there is cholesterol crystal deposition in an intraluminal location (within Rokitanky-Aschoff sinuses)
In cholesterolosis, there is cholesterol and triglyceride deposition within the gallbladder wall and is associated with the formation of cholesterol polyps
Note: Both are benign and the distinction is clinically irrelevant.
Gallbladder adenomyomatosis
Note: This is the comet-tail artifact (highly specific for adenomyomatosis).
What are the 3 major forms of gallbladder adenomyomatosis?
- Segmental (annular)
- Fundal (localized)
- Diffuse (generalized)
Note: The localized form can’t be reliably differentiated from gallbladder cancer.
Porcelain gallbladder
Note: Should have cholecystectomy due to increased risk for gallbladder cancer.
Treatment for porcelain gallbladder
Cholecystectomy (due to increased risk for gallbladder cancer)
What is the most common type of gallbladder polyp?
Cholesterol (not actually polyps, but enlarged papillary fronds full of cholesterol laden macrophages)
Note: Adenomas and papillomas are much less common.
Management of incidental gallbladder polyps
- <5 mm (none)
- 5-10 mm (annual ultrasound to look for growth)
- > 10 mm (consider surgical removal)
What features of a gallbladder polyp make you more suspicious about malignancy?
- Large size (>5 mm)
- Sessile (not pedunculated)
- Solitary (multiple are more likely to be cholesterol)
- Enhancement greater than adjacent gallbladder wall
- Internal flow on color Doppler
- Growth
Elderly woman with RUQ pain, weight loss, anorexia, and a longstanding history of gallstones…
Think gallbladder cancer
Note: Most gallbladder cancers are associated with gallstones (85%).
Risk factors for gallbladder cancer
- Gallstones (especially Mirizzi syndrome)
- Primary sclerosis cholangitis
- Chronic cholecystitis
- Porcelain gallbladder
- Large gallbladder polyps (>1 cm)
Prognosis of gallbladder cancer
Horrible (due to late presentation because it is usually asymptomatic early on)
Note: 80% of cases have direct tumor invasion of the liver or portal nodes at the time of diagnosis.
