BILE DUCT
BILIARY CIRRHOSIS
B
bile duct
Any of the ducts by which
bile
is carried from the liver, first to the gall-
bladder and then to the duodenum (the
first section of the small intestine). The
bile duct system forms a network of
tubular canals. Canaliculi (small canals)
surround the liver cells and collect the
bile. The canaliculi join together to
form ducts of increasing size. The ducts
emerge from the liver as the 2 hepatic
ducts, which join within or just outside
the liver to form the common hepatic
duct. The cystic duct branches off to the
gallbladder; from this point the com-
mon hepatic duct becomes the common
bile duct and leads into the duodenum.
(See also
biliary system
.)
LOCATION
bile duct cancer
See
cholangiocarcinoma.
bile duct obstruction
A blockage or
constriction of a bile duct (see
büiary
system).
Bile duct obstruction results in
accumulation of bile in the liver
(choles-
tasis)
and
jaundice
due to a buildup
of
bilirubin
in the blood. Prolonged
obstruction of the bile duct can lead
to secondary
biliary cirrhosis.
The most
common cause of obstruction is
gall-
stones.
Other causes include a tumour
affecting the pancreas (see
pancreas,
cancer of),
where the bile duct passes
through it, or cancer that has spread
from elsewhere in the body.
Cholangio-
carcinoma
(cancer of the bile ducts) is a
very rare cause of blockage. Bile duct
obstruction is a rare side effect of cer-
tain drugs. It may also be caused by
cholangitis
(inflammation of the bile
ducts), trauma (such as injury during
surgery), and rarely by
flukes
or worms.
Bile duct obstruction causes “obstruc-
tive” jaundice, which is characterized by
pale-coloured faeces, dark urine, and a
yellow skin colour. There may also be
itching. Other symptoms may include
abdominal pain (with gallstones) or
weight loss (with cancer). Treatment de-
pends on the cause, but surgery may be
necessary. Gallstones may be removed
with an endoscope (see
ERCP
).
bilharzia
Another name for the tropical
parasitic disease
schistosomiasis
.
biliary atresia
A rare disorder, present
from birth, in which some or all of the
bile ducts
fail to develop or have devel-
oped abnormally. As a result,
bile
is
unable to drain from the liver (see
chole-
stasis). Unless the atresia can be treated,
secondary
biliary cirrhosis
will develop
and may prove fatal. Symptoms include
deepening
jaundice
, usually beginning a
week after birth, and the passing of dark
urine and pale faeces. Treatment is by
surgery to bypass the ducts. If this fails,
or if the jaundice recurs, a
liver trans-
plant
is the only possible treatment.
biliary cirrhosis
An uncommon form of
liver
cirrhosis
that results from prob-
lems with the bile ducts, either due to
an
autoimmune disorder
known as pri-
mary biliary cirrhosis, or a longstanding
blockage. Primary biliary cirrhosis affects
mainly middle-aged women and seems
to be linked with a malfunction of the
immune system
. Secondary biliary cir-
rhosis results from prolonged
bile duct
obstruction
or
biliary atresia.
In both
types, liver function is impaired due to
cholestasis
(accumulation of bile in the
liver). In primary biliary cirrhosis, the bile
ducts within the liver become inflamed
and are destroyed. Symptoms include
itching,
jaundice
, an enlarged liver, and
sometimes abdominal pain, fatty diar-
rhoea, and
xanthomatosis. Osteoporosis
may develop. Symptoms of liver cirrhosis
and
liver failure
may occur after several
years. Drugs can minimize complications
and relieve symptoms such as itching. A
liver transplant
is the only long-term cure.
72
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