Bma Illustrated Medical Dictionary

bile ductAny 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.)

bile duct cancerSee cholangiocarcinoma.

bile duct obstructionA blockage or

constriction of a bile duct (see biliary

system). Bile duct obstruction results in

accumulation of bile in the liver (choles-

tasis) and jaundicedue 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

BILE DUCT BILIARY CIRRHOSIS

B

Pancreas Liver

Stomach

DETAIL

Cystic duct

BILE DUCT

Common hepatic duct

Gallbladder

LOCATION

Common

bile duct

Duodenum

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 flukesor 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).

bilharziaAnother name for the tropical

parasitic disease schistosomiasis.

biliary atresiaA rare disorder, present

from birth, in which some or all of the

bile ductsfail to develop or have devel-

oped abnormally. As a result, bileis

unable to drain from the liver (see chole-

stasis). Unless the atresia can be treated,

secondary biliary cirrhosiswill 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-

plantis the only possible treatment.

biliary cirrhosisAn uncommon form of

liver cirrhosisthat results from prob-

lems with the bile ducts, either due to

an autoimmune disorderknown 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 bileduct

obstructionor 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 failuremay occur after several

years. Drugs can minimize complications

and relieve symptoms such as itching. A

liver transplantis the only long-term cure.