A 45-year-old woman comes to the office due to several months of episodic right upper quadrant abdominal pain associated with nausea. The pain is often brought on by fatty meals and subsides in 1-2 hours. The patient has no fever, vomiting, diarrhea, melena, or bright red blood per rectum. Her BMI is 31.2 kg/m². Physical examination is unremarkable. A cholecystokinin stimulation test is performed and shows slow and incomplete gallbladder emptying. This patient is most likely to have which of the following pathologic findings?

Question

Quizplus · Accepted Answer

11ec160b_3946_b8ec_9249_658c4a3fdcc7_MD0001_00 This patient's slow/incomplete gallbladder emptying in response to cholecystokinin stimulation is consistent with gallbladder hypomotility. The gallbladder functions to actively absorb water from bile; conditions that cause gallbladder hypomotility result in excessive dehydration of bile. This promotes the precipitation and accumulation of particulate material (eg, cholesterol monohydrate crystals, calcium bilirubinate, mucus) in bile, forming viscous biliary sludge. Sludge formation may be asymptomatic or cause biliary colic (right upper quadrant abdominal pain associated with nausea) and is a known precursor to stone formation (particularly cholesterol stones). Complications such as acute cholecystitis and cholangitis can also occur in patients with biliary sludge. (Choices B and C) Pigment gallstones can be brown or black and arise from conditions that increase the amount of unconjugated bilirubin in bile. Brown pigment stones are associated with biliary tract infections (microbes producing β-glucuronidases), whereas black stones occur with chronic hemolytic anemias (eg, sickle cell disease) and increased enterohepatic cycling of bilirubin (eg, Crohn disease, which also decreases enterohepatic cycling of bile acids). This patient has no risk factors for pigment stones, and her gallbladder dysmotility makes biliary sludge a more likely diagnosis. (Choice D) Cystinuria is an autosomal recessive condition characterized by a defect in an amino acid transporter gene, resulting in elevated urinary cystine concentrations. Patients typically present with cystine kidney stones during childhood or adolescence. (Choice E) Individuals with high serum uric acid levels are at increased risk of developing uric acid kidney stones. Hyperuricemia can be caused by uric acid underexcretion (eg, thiazide diuretics) or overproduction (eg, tumor lysis syndrome). Educational objective: The gallbladder functions to actively absorb water from bile. Gallbladder hypomotility causes the bile to become concentrated, promoting precipitation and accumulation of particulate material. This forms a viscous biliary sludge that can cause transient bile duct obstruction (biliary colic) and promote cholesterol gallstone formation. __________ References: Biliary sludge: the sluggish gallbladder. (http://www.ncbi.nlm.nih.gov/pubmed/12974509) Gallbladder sludge: what is its clinical significance? (http://www.ncbi.nlm.nih.gov/pubmed/11276386) Lithogenesis and bile metabolism. (http://www.ncbi.nlm.nih.gov/pubmed/18992590)

A 45-Year-Old Woman Comes to the Office Due to Several