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Liver Basics
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Overview of the liver
Your liver is one of the largest and most important organs in your body. You have only one liver. It is the size
of a football and weighs about 3 pounds in the average-size person. It is reddish-brown. Your liver is located
on the right side of your abdomen behind your lower ribs, and your ribs help to protect your liver.
The liver is a filter
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Your liver has many important jobs. One of the jobs that the liver does is to act as a "filter" for
your body; it filters or detoxifies the blood. Almost all the blood in your body passes through
the liver. As blood passes through the liver, it breaks down substances, such as prescription or
over-the-counter drugs, street drugs, alcohol, and caffeine. Our bodies naturally produce some harmful (toxic)
chemicals or poisons, and the liver also breaks those down. In this way the liver acts as a filter to clean your blood.
The liver is a factory
The liver is also a "chemical factory" -- performing over 500 chemical functions in your body! The liver takes certain
materials in your body and turns them into something else. For example, your liver turns proteins and sugars into things
that your body needs. The liver produces blood-clotting factors that are needed to help you heal after an injury. It also
stores vitamins, hormones, cholesterol, and minerals. Your liver lets go of these chemicals and nutrients when your body
needs them, and they flow into your bloodstream. The liver also produces a greenish fluid called bile. Tubes, called "bile
ducts," connect the liver and another organ, the gallbladder, to the small intestine. The bile that is made by the liver helps
to digest fats in the small intestine.
Summary of liver functions
The liver:
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Filters your blood
Makes proteins, including blood-clotting factors (needed to help you heal)
Stores vitamins, sugars, fats, and other nutrients
Helps regulate hormones
Releases chemicals and nutrients into the body when needed
Makes bile needed for digesting fats
And much more
Liver disease and other complications
Liver disease is caused by damage to the liver. Liver damage can be caused by many things, including:
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Viruses (such as the hepatitis viruses)
Drinking alcohol heavily
Being very overweight
Certain medications--for example, acetaminophen (Tylenol), can cause severe liver damage in people who also have
heavy alcohol use
 Exposure to industrial chemicals, including cleaning solvents, aerosolized paints, and paint thinners
Liver damage can lead to livers that are swollen, shrunken, hard, or scarred. Such livers do not work well, and you can get
very sick, or even die, if your liver stops working altogether.
Symptoms of liver disease
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Acute
If something happens to the liver suddenly, it is "acute." Some acute liver problems will cause symptoms suddenly as well.
Symptoms of acute liver disease can include:
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Tiredness or weakness
Jaundice (yellowing of the eyes and skin)
Fever
Nausea and vomiting
Dark urine or very pale colored stools
Pain under the ribs on the right side
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Up to half of all people with acute liver disease have no symptoms at all. Some types of acute liver disease get better
without treatment, and the liver heals itself entirely. On rare occasions an acute liver injury can require hospitalization and
even liver transplant right away.
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Chronic
If something is continuing to affect the liver over time, after 6 months it is "chronic." Many people with chronic liver
problems will have no symptoms at all and may not even know they have a liver problem. Sometimes they develop
symptoms only when the liver has been damaged for many years.
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Hepatitis
The word "hepatitis" means inflammation or swelling of the liver. Many things can trigger this, and the hepatitis C virus is
just one of them. Medications, alcohol, and even some genetic diseases can cause inflammation. (Genetic diseases are
ones that are passed down from your biological parents.) Sometimes liver inflammation gets better on its own, but
sometimes, as in the case of chronic hepatitis C, treatment with medications is required to stop the inflammation. If you
have hepatitis, you need to be very careful not to do things that might irritate your liver even more. Alcohol irritates the
liver, even in someone who doesn't have any other liver problems.
Summary: "Hepatitis" means inflammation of the liver. It can be caused by:
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Genetic diseases
Medications (including over-the-counter drugs)
Alcohol
Viral hepatitis (such as hepatitis A, hepatitis B, and hepatitis C)
Fibrosis and cirrhosis
Anything that damages the liver over many years can lead the liver to form scar tissue. Fibrosis is the first stage of liver scarring.
When scar tissue builds up and takes over most of the liver, this is a more serious problem called cirrhosis (pronounced "sir-o[70] sis"). Scar tissue cannot perform any of the jobs of normal liver cells, and this causes a person with cirrhosis to slowly become ill.
Not everyone with hepatitis or a chronic liver problem will develop cirrhosis. Cirrhosis does not happen overnight. In the early
years of having cirrhosis, many people will have no obvious signs or be ill and many may not even be aware they have cirrhosis at
all. Cirrhosis can be caused by anything that damages the liver after years of irritation, not just alcohol. However, heavy alcohol
use and having the hepatitis C virus for a long time (such as 20 to 30 years) increases your risk. Over time, cirrhosis can lead a
[75] person to become ill. Symptoms can include fatigue, difficulty thinking clearly, fluid in the abdomen, bleeding in the intestines,
and poor blood clotting. Anyone who has cirrhosis, with or without symptoms, needs very close medical attention.
Alcoholic liver disease
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Alcoholic liver disease is a common form of liver disease in the United States. People get alcoholic liver disease by drinking
large amounts of alcohol for many years. It doesn't matter whether the alcohol comes from hard liquor, beer, or wine. Any
type of alcohol can cause liver damage. One unit of an alcoholic beverage contains 10 grams of alcohol. A unit is roughly
equivalent to:
 one 12-ounce bottle of beer (5% alcohol)
 one 4-ounce glass of wine (12% alcohol)
 one 1-ounce shot of hard liquor (40% alcohol)
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So how much alcohol is too much? It depends on whether you're a man or a woman. Studies have shown that women
experience liver disease at lower levels of alcohol intake than men. Many liver specialists would agree that liver disease is
likely at these levels: For women: 4 or more units of alcohol daily for at least a year; For men: 6 or more units of alcohol
daily for at least a year. Some people will experience liver damage even if they drink much less. The good news is that the
livers of heavy drinkers can improve if they stop drinking entirely.
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Fatty liver
Fatty liver is the buildup of fat in liver cells. It is probably the most common type of liver disease in the United States. Fatty liver
by itself rarely leads to severe liver damage. Fatty liver can result from drinking too much alcohol. It can also happen in people
who rarely drink. In this case, it is called "nonalcoholic fatty liver disease" or "nonalcoholic steatohepatitis," or NASH. ("steato-"
means fat.) With NASH, a patient's liver shows some inflammation that in some cases can lead to liver damage and cirrhosis
[95] (scarring of the liver tissue). It is not clear why fat builds up in the liver, but people are more likely to develop the condition if
they have diabetes, are overweight, or have high levels of cholesterol or blood fats (called "triglycerides"). The amount of fat in
the liver may decrease when overweight people lose weight, when diabetics have well-controlled blood sugars, and when
cholesterol and triglyceride levels are lowered.
Liver cancer
[100} Like all other body organs, your liver can get cancer. Liver cancer is a disease in which some of the cells in your liver begin to
reproduce faster than they should. This can lead to liver tumors, which are generally diagnosed by taking pictures of the liver
with ultrasound, computerized tomography (CT) scan, or magnetic resonance imaging (MRI). Having hepatitis B or hepatitis C
can increase your chances of getting liver cancer, called hepatocellular carcinoma (or "HCC"). Most people with liver cancer do
not have any symptoms from it early on. Those who do have symptoms often have some pain in the area of their liver (right side
[105] of the abdomen, under the ribs), or they may have a build-up of fluid in their abdomen (called "ascites"). Liver cancer is very
serious and can be deadly. If you find out that you have liver cancer, you need to get treated as soon as possible.
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Liver transplants
Liver transplants are considered only when a patient might die from liver disease. This is sometimes the case when a patient has
liver cancer or when someone has advanced liver disease and the liver has stopped functioning properly. Being considered for a
[110] liver transplant does not mean that a patient is in danger of dying right away. Liver transplantation is a long process that involves
a lot of medical care. After a transplant, a patient needs lifelong drugs to keep the body from rejecting the new liver, and lifelong
follow-up care from a specialist. Survival rates after a transplant are higher than 90% at 1 year, and patients usually have a good
quality of life after their recovery.
Tests for liver damage
[115] Most people with chronic liver disease will have no ongoing symptoms, and the damage will be detected only by blood tests. The
tests (called a “liver panel”) measure:
 your level of liver enzymes (see next section)
 your level of bilirubin (pronounced "billy-roo-bin"), which rises when the liver is not working well
 a protein called albumin (pronounced "al-byoo-min"), whose levels go down when the liver is damaged
[120] Doctors can run more blood tests if they need to in order to find out what is causing the damage to your liver. Ultrasound, CAT
scans, and MRI are the three main methods of taking pictures of the liver. They can often show if the liver injury has become
serious. A liver biopsy, in which a needle is used to take a sample of the liver itself, can tell even more about the liver's health.
Some people with liver problems can have a swollen liver. Others may have severe scarring or a shrunken liver. During an
examination, a doctor can feel the liver to find out if it is shrunken, hard, or swollen.
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Liver enzymes
Enzymes are proteins found in your body that speed up certain chemical reactions. Liver enzymes
perform these jobs within the liver. Two of the common aminotransferase enzymes are known as
"AST" and "ALT." If the liver is damaged, AST and ALT pass into the bloodstream. When your doctor
looks at the results from your blood tests, AST and ALT values are higher than normal if your liver is
damaged. The damage to the liver can come from viruses, such as the hepatitis C virus, over-thecounter drugs, and prescription and street drugs. If your doctor starts you on a certain medication, he or she may need to
monitor your blood chemistries to make sure the medication is not causing further harm to your liver.
Reversing liver damage
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The liver is one of the only organs in the body that is able to replace damaged tissue with new cells rather than scar tissue.
For example, an overdose of acetaminophen (Tylenol) can destroy half of a person's liver cells in less than a week. Barring
complications, the liver can repair itself completely and, within a month, the patient will show no signs of damage.
However, sometimes the liver gets overwhelmed and can't repair itself completely, especially if it's still under attack from a
virus, drug, or alcohol. Scar tissue develops, which becomes difficult to reverse, and can lead to cirrhosis.
Keeping your liver healthy
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Here are some things to remember about keeping your liver healthy:
 Don't have unsafe sexual contact.
 Don't inject drugs like heroin or cocaine.
 Don't drink alcohol. Alcohol is a poison to the liver and also can make liver diseases such as hepatitis much
worse. If you do drink, drink lightly.
 Don't share any personal items such as razors or toothbrushes that might have blood on them.
 Ask your doctor about getting vaccinated against hepatitis A and B. There is currently no vaccine against the
hepatitis C virus.
 Follow strict food safety guidelines. Make sure that the water you drink and the food you eat are clean,
especially when traveling to other countries. Most cases of infection with hepatitis A result from poor
cleanliness during food preparation.
 If you take any medications, make sure your doctor knows about them. Also tell your doctor about any over-thecounter medicines, supplements, and natural or herbal remedies that you use. Certain medicines taken at the
same time can cause damage to your liver, even if you can buy them without a prescription.
 Maintain a healthy body weight.
 Control blood sugars if you have diabetes.
 Keep cholesterol and blood fats within the recommended range.
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