Definition
Presence of concretions in the gallbladder or bile ducts.
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Imaging
Erect and supine abdominal radiographs are useful.
Approximately 15% of gallstones are radiopaque and can be visualized
on plain x-ray.
A porcelain gallbladder (heavily calcified) should be removed
surgically because of increased risk of gallbladder cancer.
Other causes of abdominal pain diagnosed with the assistance of
x-rays include perforated viscus, bowel obstruction, calcific
pancreatitis, and renal stones.
Ultrasound
Ultrasound (US) is the most sensitive and specific test for the
detection of gallstones.
US provides information about the size of the common bile duct and
hepatic duct and the status of liver parenchyma and the pancreas.
Thickening of the gallbladder wall and the presence of
pericholecystic fluid are radiographic signs of acute cholecystitis.
Computerized tomography scanning
CT scanning often is used in workup of abdominal pain without
specific localizing signs or symptoms.
CT scanning is not a first-line study for detection of gallstones
because of greater cost and the invasive nature of the test.
When present, gallstones usually are observed on CT scan.
Technetium Tc 99m image display and analysis scintigraphy scan
Technetium Tc 99m image display and analysis (iminodiacetic acid
[IDA]) scintigraphy (hepatoiminodiacetic acid [HIDA]) scan does not
detect gallstones.
HIDA scan identifies an obstructed gallbladder (e.g., gallstone
impacted in the neck of the gallbladder).
HIDA scan is the most sensitive and specific test for acute
cholecystitis.
A poorly contracting gallbladder (biliary dyskinesia) might cause
the patient's symptoms, and HIDA scan makes the diagnosis.
Acute acalculous cholecystitis is diagnosed most accurately with
HIDA scan.
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Pathophysiology:
Although gallstones can form anywhere in the biliary
tree, the most common point of origin is within the gallbladder.
Three types of gallstones exist: pure cholesterol, pure pigment, and
mixed.
Under normal conditions, a delicate balance occurs among the levels
of bile acids, cholesterol, and phospholipids. A disparity in this
balance, especially with the supersaturation of cholesterol,
predisposes patients to the formation of lithogenic bile and the
subsequent development of cholesterol-type gallstones.
Pigmented gallstones are composed of calcium bilirubinate and appear
in 2 major forms: black and brown. Hemolysis and liver disease are
associated with the black stones; the brown, earthy stones more
frequently are formed outside the gallbladder and often are
associated with bacterial infections of the biliary tract.
Bile stasis predisposes to the formation of biliary sludge and
eventual formation of gallstones and commonly is observed in
patients who are unable to take enteral nutrition.
Frequency:
In the US: About 5-10% of the population is estimated to be at risk
of developing gallstones.
Internationally: The prevalence of cholelithiasis in other Western
cultures is similar to that in the United States, but it appears to
be somewhat lower in Asia. In most Western countries, the majority
of gallstone cases remain asymptomatic throughout the patient’s
life.
Mortality/Morbidity:
Mortality and morbidity are related directly to the complications of
the disease and its surgical treatment. Approximately 10% patients
with gallstones have common bile duct stones as well.
The natural history of common bile duct stones is not known
completely. Gallstones can cause obstruction of the common bile
duct, causing jaundice. Cholangitis, a potentially life-threatening
infection, can follow biliary obstruction.
Obstruction of the neck of the gallbladder causes bile stasis, which
can lead to inflammation and edema of the gallbladder wall. Sequelae
of this condition include acute cholecystitis secondary to
compromised lymphatic, venous, and, ultimately, arterial supply to
the gallbladder. The latter can lead to gangrene or abscess
formation.
Race: Mexican Americans and American Indians, especially the Pima
tribe, have an increased predisposition to gallstone formation.
Sex: Women are more likely to develop gallstones than men, with a
ratio of 2:1.
Classically, gallstones occur in obese, middle-aged women, which
leads to the popular mnemonic, fat fertile forties.
Oral contraceptive pills with high estrogen content increase the
incidence of gallstones.
Age: Incidence increases with age.
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Treatment:
Cholecystectomy
Percutaneous stone removal
Endoscopic retrograde stone removal if the stones are near the
ampulla
Lithotripsy
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Image 1
A selction of stones
Image 2 MR scan of biliary system
Image 3 Radionuclide HIDA
Scan
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Useful Link
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