Duodenal Biliary Drainage
Medical Author: Jay W. Marks, M.D.
Medical Editor: William C. Shiel, Jr., MD, FACP, FACR
What is duodenal biliary drainage?
Duodenal biliary drainage is a little-used procedure
that sometimes can be helpful in diagnosing gallstones.
How is duodenal biliary drainage done?
For duodenal biliary drainage, a
thin plastic or rubber tube with several holes at its tip is passed through a patient's anesthetized nostril,
down the back of the throat, through the esophagus and stomach, and into the duodenum where the bile and pancreatic ducts enter the
small intestine. This is
accomplished with the help of fluoroscopy,
a type of X-ray. Once the tube is in
place, a synthetic hormone related to cholecystokinin is injected intravenously.
The hormone causes the gallbladder to contract and squeeze out its concentrated
bile into the duodenum. The bile then is sucked up through the tube and examined
for the presence of cholesterol and pigment particles under a microscope.
A modification of duodenal biliary drainage involves
collection of bile through an endoscope at the time of an upper gastrointestinal
endoscopy -- either by EGD (esophagogastroduodenoscopy) or by
ERCP (endoscopic retrograde cholangio-pancreatography).
Why might duodenal biliary drainage be done?
Gallstones begin as microscopic particles of cholesterol
or pigment that grow in size. Once the particles grow large enough to become
gallstones, they can obstruct the bile ducts and cause problems. It is clear
that some people who develop the symptoms and complications of
gallstones -- biliary colic, cholecystitis,
or pancreatitis
-- have only these microscopic particles in their gallbladders, particles too small to obstruct the bile ducts.
There are two possible
explanations for how obstruction might be occurring in this situation. The first is that a small gallstone obstructed the bile ducts but finally passed through the
bile ducts into the intestine. The second is that the particles passing through the bile ducts "irritate" the ducts, causing spasm of the muscle within the walls of the ducts (which obstructs the duct) or causing inflammation of the duct so that the wall of the duct swells (which also obstructs the duct).
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