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GALLSTONES–
LAPAROSCOPIC CHOLECYSTECTOMY
BILE
The
liver is the largest gland in the body, and controls the metabolism.
As a result, waste substances are released in a liquid called bile
(gall). Bile includes cholesterol (in a different form to that
circulating in the blood), bile pigments which colour the bile
yellow-brown, and bile salts needed for digestion. The liver
produces up to three cups of bile per day. Apart from getting rid of
waste, bile has an essential action as a detergent to dissolve fats
from food so that they can be digested properly. Bile passes through
a series of tubes called the bile ducts, which lead it from the
liver to the gut. About halfway down the bile duct, there is a side
alley leading to the gallbladder.
THE GALLBLADDER
The
gallbladder is a small pear-shaped bag located beneath the liver on
the right side of the abdomen. The gallbladder stores bile, and
concentrates it holding ready for digestion. The gallbladder can
store up to one cup of concentrated bile. Shortly after eating a
meal, the gallbladder squeezes and its bile is released back into
the bile duct, and then into the gut. Bile helps fat digestion, and
some bile is reabsorbed, returning to the liver, whilst the waste
materials within it are eliminated from the body in the stools -
which is why they are usually coloured brown.
GALLSTONES
Gallstones
are solid pieces of material that form in the gallbladder, and are
usually a little softer than stones. Around one in ten people have
gallstones, most commonly as they get into mid-life. Women develop
gallstones more commonly than men and at a younger age. Gallstones
vary in size and may be as small as sand grains or as large as a
plum. The gallbladder may develop a single, often large, stone or
many smaller ones, even several thousand. As the gallbladder
concentrates bile, it can cause cholesterol and/or bile pigments to
crystallise, eventually growing large enough to form gallstones.
This can be encouraged by a combination of factors, including
inherited body chemistry, body weight, sluggish gallbladder
movement, and perhaps diet. Some proteins in bile can promote or
inhibit cholesterol crystallisation. Obesity is a major risk factor
for gallstones, with a large clinical study showing that even being
moderately overweight increases the risk of developing gallstones,
probably because it causes excess cholesterol in bile, low bile
salts, and decreased gallbladder emptying. Curiously, very low
calorie, rapid weight-loss diets, and prolonged fasting, seem to
also cause gallstone formation. Increased levels of the female
hormone oestrogen, from pregnancy, hormone therapy, or contraceptive
pills may increase bile cholesterol levels and decrease gallbladder
emptying. Low-fibre (roughage), high-cholesterol diets, and diets
high in starchy foods have been suggested as contributing to
gallstone formation. Cholesterol stones are white or yellow and make
up about 80% of gallstones, but most are mixed and contain some
pigment. They develop when bile contains an imbalance, with too much
cholesterol and not enough bile salts. Pure pigment stones are
small, dark and made of bilirubin, accounting for the other 20%, and
may result from cirrhosis, biliary tract infections, and hereditary
blood cell disorders, such as sickle cell anaemia or spherocytosis.
WHAT
DISEASES CAN GALLSTONES CAUSE?
Most
people with gallstones do not know they have them, as they do not
experience any trouble from them. However, gallstones can lead to
gallbladder pain, or leave the gallbladder and enter the bile duct,
also causing blockage leading to (yellow) jaundice, inflammation
with rigors (shivering), or acute pancreatitis. Gallbladder pain can
be caused by muscular spasm when the gallbladder attempts to expel
the stones (biliary colic), or more seriously, irritation or
inflammation due to infection (acute cholecystitis). The pain varies
from a brief feeling of indigestion after eating, to severe attacks
of up to several hours duration, with nausea, vomiting or belching,
and sometimes bloating. Pain is usually felt in the middle or right
side of the upper abdomen, and sometimes, due to the way the
gallbladder develops in early life, pain can be 'referred' around
the right rib margin pain to the back and around the shoulder or
shoulder blade. In jaundice bile cannot flow into the gut and spills
into the blood, causing a yellow skin and eye colour. Digestion is
also impaired causing bloating, the stools turn a putty colour, and
due to the overspill into blood, some, urine becomes dark. Bile
infection can occur in this situation causing 'rigors' or severe
shivering attacks.
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