• biliary sand/microlithiasis
• precursor to stones
• cholecystitis, colic, pancreatitis

Biliary sludge is a common finding on GB sonography. It is mainly comprised of calcium bilirubinate granules and lesser amounts of cholesterol crystals. It can be asymptomatic. Risk factors are rapid weight loss, gastric surgery, total parenteral nutrition (tpn) in fact you see it quite frequently in ICU patients that are receiving tpn. Some medicines may predispose to sludge like Rocephin. It is considered a precursor to stone development, in one study 5-15% of patients with sludge developed gallstones. 

• 

• 

On ultrasound you’ll see low level echoes to echogenic debris that layers in the dependant part of the GB and is mobile with patient position. Sludge may aggregate into clumps which may simulate masses or polyps. This is known as tumefactive sludge. The gallbladder may also be completely filled with sludge making the whole GB complex isoechoic to the liver known as hepatization.