Mod 6-1 Chole Flashcards
How many people are affected by cholelithiasis in the U.S. every year?
20 million people
The ______ population are more commonly affected by cholelithiasis.
female
Cholelithiasis is another term for __________.
gallstones
What are the two types of gallstones?
- Cholesterol stones
- Pigment stones
Which type of gallstones are predominant in the US? And which occurs more frequently in the tropics and Asian countries?
- U.S. - 75% are cholesterol stones
- Tropics/Asia - Pigment stones
What do genetic predispositions associated with higher incidence include?
- Family history of the disorder
- Age older than 40
- Excess weight
- Female sex
When can gallstones develop?
- Whenever bile contains insufficient bile salts and lecithin in proportion to cholesterol to maintin the cholesterol in solution.
- Increased hepatic synthesis of cholesterol
What can cause a decrease in the amount of bile salts present?
Decreased reabsorption in the terminal ileum as a result of inflammatory disease or surgical resection
Cholesterol is radio______.
lucent.
*Most gallstones are radiolucent
How can we visualize cholesterol stones?
Contrast examinations or ultrasound
What percentage of patients are gallstones detectable on plain abdominal radiographs and why?
20% because the gallstones contain sufficient calcium to be detectable.
What three ways can a gallstone appear?
- A central nidus (focus) of calcification
- A laminated appearance (with alternating opaque and lucent rings)
- Calcification around the periphery
*Occasionally a nonopaque stone may contain gas-fllled fissures that produce the mercendes-benz sign (triradiate pattern)
What method was once used to visualize gallstones?
Oral cholecystography (OCG) now replaced with ultrasound
Solitary gallstones are usually ______; multiple stones are generally ______.
rounded; faceted (many sides)
Describe characteristics of large number of stones
- Sandlike or gravel-like consistency
- Visible only when they layer out on radiographs obtained using a horizontal bean with the patient in an erect or lateral decub position.
- Infrequently coated with tenacious mucus and adheres to the gallbladder wall
What range of sizes do gallstones range?
From grain of sand to those 1-2 stones large enough to fill the entire gallbladder.
Why is sonography the method of choice for demonstrating gallstones?
Because it does not depend upon patient compliance in taking the contrast material and can effectively demonstrate the biliary tree as well as the gallbladder.
What causes acute cholecystitis?
Usually caused by an obstructing stone in the cystic duct leading to the gallbladder.
What does the obstruction that leads to acute cholecytitis cause?
Irritation of the wall of the duct and the signs of inflammation become apparent.
What can be used to diagnose cholecystitis?
Sonography and nuclear medicine
*Radiographic methods ar enot useful at all.
What is the radiographic technique for the gallbladder?
- With a kVp that is less than that used for routine abdominal radiograph.
- To improve contrast, use 70 kVp or less
What is acute cholecystitis?
Inflammation of the gallbladder
What causes most cases of acute cholecystitis? What percentage?
95% occurs after obstruction of the cystic duct by an impacted gallstone.
*Gallstones may injure hte mucosal wall allowing bacteria to enter.
How can large number of stones be visible on a radiograph?
When they layer out using a horizontal beam with the patient erect or lateral decubitus position.
How often are gallstones coated with tenacious mucus and adhere to gallbladder wall?
infrequently
What can lead to nonvisualization of the gall bladder in OCG?
- Malabsorption of the radiopaque contrast material (hepatocellular dysfunction)
- Intrinsic disease of the gallbladder
If these can be excluded, evidence of gallbladder disease
When using ultrasound to visualize the gallbladder, what else can be evaluated?
Billiary tree and hepatic parenchyma
Ultrasound diagnossi of acute cholecystits requries the demonstration of…..
distended gallbladder containing gallstones.
*Also edema of wall and focal tenderness
What modality is used with cholecystitis when ultrasound findings are inconclusive?
MRI
