Gallstones
Gallstones, also known as bilestones or
biliary calculi, are lumps of solid matter which harden out of liquid
bile. They are composed of cholesterol, bile pigments, bile salts,
calcium salts, and excretory elements, in varying proportions.
Gallstones are typically green, yellow, brown, or black in color,
depending on the proportions of their content. Other physical
properties like hardness, size, and density may also vary accordingly.
As the name suggests, gallstones or biliary calculi can develop
anywhere along the biliary tract where bile is present - in the
gallbladder, in the various bile ducts, and in the liver (intrahepatic
stones). They range in size from a grain of sand to a golf ball, so the
gallbladder and liver can hold thousands of small stones, or a few big
stones, or both.
The formation of gallstones (cholelithiasis) occurs when bile
contains more cholesterol than it can keep in liquid form, or when
chemical imbalances cause normal cholesterol levels in bile to become
less soluble and crystallize.
Cholesterol crystallization into stones may be the result of a
high-cholesterol diet, excretion of certain drugs into bile, stagnant
bile, an unhealthy liver producing unhealthy bile, or simply a person's
natural tendency. Drugs which suppress cholesterol in blood actually
transfer the excess cholesterol into bile, thus increasing the risk of
gallstones.
Gallstone
Symptoms
The majority of people with gallstones remain
free of symptoms for many years, and may never know they have
gallstones. However, when symptoms do develop, they tend to recur. Some
of the straightforward symptoms of gallstones are:
- pain in the upper abdomen
- pain between the shoulder blades,
sometimes up to the nape
- enlarged and tender area below the
right rib cage
- abdominal bloating after meals
- yellow skin and eyes (jaundice)
- nausea or vomiting
- fever or chills
Gallstone colic, the pain caused by
gallstones, is severe and steady. It arises when a stone moves out of
the gallbladder or liver and enters the bile ducts. Each attack can
last from 1 to 4 hours, followed by a lingering soreness that persists
for about a day. The pain can be so intense that people become
desperate enough to get rid of their gallbladder.
Gallstone Diagnosis
The major component of most gallstones is
cholesterol, which is not radio-opaque. This explains why many
gallstones do not show up on a plain X-ray; only stones with high
calcium content are radio-opaque and visible. Oral cholecystogram, an
X-ray of the gallbladder after ingesting a
radio-opaque material, is reasonably effective but is rarely used
because of possible adverse reactions.
Ultrasound scanning is the most common method for detecting stones in
the gallbladder. It uses sound waves which will bounce off solid
objects to show their presence. Ultrasound is non-invasive, painless,
does not involve radiation, and has no known side effects.
However, a drawback of ultrasound scanning is that excess fatty tissue
surrounding the gallbladder can block the sound waves, and produce
false negative results. This means that obese people may not be easily
diagnosed with gallstones. Ultrasound scanning also has difficulty in
detecting stones lodged in the bile ducts and liver.
When strong symptoms of gallstones cannot be cannot be confirmed by
ultraound or X-ray, more expensive techniques like computed tomography
(CT scan), endoscopic retrograde cholangiopancreatography (ERCP), or
magnetic resonance cholangiopancreatography (MRCP) can be used.
Gallstone Effects on Health
In the
long-term, gallstones can congest and damage the all-important liver,
slowly and indirectly causing health problems which seem unrelated,
such as high
blood cholesterol, high blood pressure (portal hypertension),
atherosclerosis, enlarged spleen, heart attack, stroke, excessive uric
acid, kidney stones, gout, headache (liver encephalopathy), general
fatigue, loss of appetite, hormone imbalance, abnormal growths, and
many more.
In order to understand the effects of
gallstones on the rest of the
body, it is necessary to look at areas which are physically related
to gallstones:
- bile, the source of gallstones
- the biliary tract, where
gallstones can form
- organs attached to the biliary
tract - liver, gallbladder, and
pancreas.
Bile
Bile is the thick digestive
fluid produced by the liver. Like gallstones, it consists of
cholesterol, bile pigments, bile salts, calcium salts, and excretory
elements. It is usually green, yellow, or brown in color, while other
physical properties like viscosity and density may also vary, depending
on the proportions of its content. Bile is needed for the following
functions:
- to emulsify fats so that they can
be digested and absorbed by the intestines
- to excrete certain waste products
from the body, such as destroyed red blood cells, excess cholesterol,
drugs, and chemical by-products
- to stimulate peristalsis in the
intestines so that the contents can be moved along easily and finally
evacuated as feces.
The
Biliary Tract
The biliary tract is a system of ducts which
carry bile from the liver to the gallbladder and the intestines. There
are thousands of bile capillaries inside the liver which join like the
twigs and branches of a tree to form two large ducts outside the liver,
the left hepatic duct and the right hepatic duct. These two ducts unite
to form the common hepatic duct, which joins the cystic duct from the
gallbladder to form the common bile duct. The common bile duct merges
with the pancreatic duct just before entering the duodenum at the
sphincter of Oddi.
 Gallstones
can form anywhere along the biliary tract
The
Liver
The liver is the largest and arguably the most
complex and important organ in the body. The ancient Chinese considered
the liver, not the heart or brain, as the center of the body which
governs health.
Located in the upper right portion of the abdomen, beneath the lungs,
above the stomach and intestines, this dark reddish-brown organ weighs
between 1.2 to 1.6 kg and acts as the body's chemical factory.
Among the hundreds of liver functions that have been identified, some
of the better-known functions are:
- Digestion
- it secretes bile which flows into the
intestines to help digest fats.
- Metabolism
- it converts nutrients from the stomach
and intestines into fats,
carbohydrates (sugar), amino acids (proteins) and vitamins, forms that
are easier for the rest of the body to use. Heat is released in the
process.
- Synthesis
- it produces cholesterol, some of which
becomes bile. The rest of the
cholesterol is used by other parts of the body to build cell membrane
and certain hormones like estrogen, testosterone and adrenal hormones.
The liver also produces blood-clotting fibrinogen and prothrombin, as
well as the anticoagulant heparin.
- Regulation
- it regulates the amount of sugar, amino
acids, hormones and other
chemical levels in the blood. Excess blood sugar is converted to
glycogen for storage in the liver. Excess amino acids and hormones are
broken down and excreted from the body.
- Storage
- it stores nutrients like glycogen, fats
and vitamins, releasing them
into the bloodstream when needed.
- Recycling
- it extracts bile salts from the small
intestine, and secretes them
again into bile.
- Detoxification
- it breaks down toxic substances and
worn-out red blood cells, then
excretes them as harmless by-products into the bile and the blood.
Chemicals from processed foods, drinks, and prescription drugs are
broken down this way.
- Excretion
- it removes waste products from the body.
By-products in the bile
enter the intestines, then leave the body through the feces.
By-products in the blood are filtered out by the kidneys, then leave
the body through the urine.
The Gallbladder
The
gallbladder is a pear-shaped muscular storage sac which holds bile,
situated below the right lobe of the liver. Bile secreted between meals
flows from the liver through the cystic duct into the gallbladder.
During a meal, the hormone cholecystokinin-pancreozymin causes the
gallbladder to contract and squeeze bile into the duodenum to help
digest fats and certain vitamins. After the food has been digested, the
gallbladder relaxes and is ready to store bile again.
Bile is continuously produced by the liver, and its viscosity changes
according to its chemical and excretory content. Bile flows easily when
it is thin, and the gallbladder serves as a good storage area so that
it does not constantly drip into the duodenum when no food is present.
Bile does not flow easily when it is thick, and the gallbladder helps
to squirt enough of it into the duodenum when food is present. In other
words, the gallbladder has a regulatory function to ensure that the
right amount of bile is released into the duodenum at the right time.
Gallstone
Complications
Complications caused directly by gallstones
are
usually accompanied by severe episodes of abdominal pain. The following
are some of these complications.
Cholecystitis
- inflammation of the gallbladder when the flow of bile from the
gallbladder is stopped. This occurs when a stone blocks the exit of the
gallbladder or enters the cystic duct.
Cholestasis
- a more serious stoppage of the flow of bile from the liver into the
duodenum. This occurs when a stone enters and blocks the common bile
duct, and can further lead to the following complications.
Jaundice
- yellow coloration of the skin and eyes, with dark urine. Even though
the flow of bile has stopped, the liver continues to produce bile. Dead
blood cells or bilirubin, which is normally excreted through bile,
backs up into the bloodstream, and is then deposited in the skin and
passed into the urine.
Cholangitis
- inflammation of the bile ducts outside the liver, due to bacterial
infection of the stagnant bile. If not overcome, this inflammation can
spread to the liver.
Biliary
cirrhosis - inflammation and obstruction of the bile ducts
inside the liver. As the inflammation spreads to the rest of the liver,
normal liver cells die and are replaced by fibrous scar tissue. The
scarring disrupts the function of the liver, and in severe cases can
lead to death. Cirrhosis is also a major risk factor for cancer.
Pancreatitis - inflammation of the pancreas when a stone
blocks the pancreatic duct or the sphincter of Oddi. Not only is the
flow of bile obstructed, pancreatic secretions into the duodenum
containing digestive enzymes are also blocked. The blockage is usually
temporary and will clear by itself; but if it continues, the blocked
enzymes will start to digest the cells of the pancreas.
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