Glossary of Liver Terms

All definitions are provided by members of the C.L.A.S.S. Scientific Advisory Board.

Click on a letter below to show the glossary term and definition. Click again to collapse the panel, and select another to open.

— A —


Without bile pigment in the stools. Causes stools to be pale in color.


Actigall (Ursodiol) is a drug used to treat some biliary disorders. The drug itself is a bile acid and after being absorbed it is excreted into bile and can result in the dissolution of certain types of gall stones that are composed predominantly of cholesterol. It is also recommended to treat primary biliary cirrhosis and appears to slow the progression of this disease. It is also used in some cases to treat biliary atresia, but there is currently insufficient evidence that it is effective in these patients.

Alagille syndrome


The term alcoholic is generally defined as someone who is addicted to alcohol. Addiction in turn is defined as a maladaptive pattern of drinking that leads to significant personal problems as defined by 3 or more of the following in the same 12 month period: 

  1. Drinking larger amounts or over longer period than intended.
  2. Persistent desire or unsuccessful efforts to cut down or control drinking.
  3. Drinking that interferes with family, friends, or job.
  4. Continued drinking despite negative consequences such as divorce, lost job, DWI conviction.
  5. Tolerance, meaning that over time it takes more alcohol to get drunk than it used to.
  6. Withdrawal, meaning that the person has unpleasant symptoms if they stop drinking.

alpha 1-antitrypsin deficiency

ammonia intoxication

Urea and ammonia are two by-products of the metabolism (usage and break-down) of proteins. They are handled and eliminated via very sophisticated mechanisms within liver cells. In the case of liver damage, be it acute or chronic (long-lasting with slow progress), the ammonia accumulates to become toxic, particularly to the brain which swells in its presence.


A technical term meaning jaundice-free.


Ascites is fluid within the abdomen. It can occur for a variety of reasons including liver disease, kidney disease, heart failure, and malnutrition. The starving children in pictures of famine stricken areas have large swollen abdomens due to ascites that is from malnutrition. Their diet contains too little protein which leads to abnormally low amounts of a protein in the blood called “albumin.”

Albumin normally keeps fluid in the blood stream through a physical force called “colloid osmotic pressure.” When the albumin level is too low, either because it is lost in the urine or because of malnutrition, the colloid osmotic pressure falls. If the colloid osmotic pressure is below venous pressure, fluid leaks out of the blood stream and ascites results.

Some people with kidney failure develop leaky kidneys that spill albumin into the urine, leading to low blood levels of albumin. People with heart failure develop ascites because pressure builds up the veins that lead to the heart. If this increased venous pressure exceeds colloid osmotic pressure, ascites results. People with liver failure develop ascites for two reasons: Since the liver makes albumin out of dietary protein, liver failure patients may have a low amount in their blood stream even if they have adequate nutrition because of the liver’s decreased ability to make new protein. Also, liver failure patients develop portal hypertension which can tend to elevate the venous pressure above colloid osmotic pressure.

avascular necrosis of the joint (also called “aseptic necrosis”)

A condition where the bone dies for unknown reasons. It is most common in the femur (thigh bone), but it can also happen in the knees and arms. The usual symptom is pain and the diagnosis is made by x-rays. Symptoms can appear before the diagnosis can be made by x-ray. Sometimes there are little or no symptoms. It is more common after kidney transplantation compared to liver and heart transplantation. Treatment may include adjustment of prednisone dosage, pain management, and sometimes joint replacement.

— B —

biliary atresia

A congenital (developmental) malformation of the biliary tract where the biliary ductules outside the liver do not form to collect the bile from the liver cells to bring it out into the intestine. According to the degree or severity of the defect, there may be different types which usually involve the gallbladder.

biliary cirrhosis

see primary biliary cirrhosis and secondary cirrhosis

biliary stasis


Bilirubin is a chemical breakdown product of hemoglobin. Hemoglobin is a substance in red blood cells that grabs onto oxygen in the lungs and carries it to the tissues in the body where it releases it. When red blood cells wear out they are trapped in the spleen and destroyed, releasing bilirubin into the blood. This type of bilirubin is called unconjugated. The liver takes the bilirubin out of the blood and conjugates it by attaching a portion of another molecule to the bilirubin molecule. Conjugated bilirubin can then be excreted in bile by the liver. The bile then goes through the bile duct into the intestine. Eventually the bile winds up exiting the body in feces. Bile gives the feces its brown color. If the liver is not producing bile or if the bile duct is blocked, the color of feces is tan.


A biopsy is whenever tissue is removed from an organ or tissue in order to tell something about the organ or tissue. There are many types of biopsies:

  • A fine needle biopsy (sometimes called a “fine needle aspiration”) involves inserting a long, very thin, needle and aspirating cells for analysis.
  • A core needle biopsy involves placing a specially designed needle into the organ in order to draw out a tiny cylinder of tissue for analysis.
  • A wedge biopsy involves an actual operation: A sliver of the organ is taken out with a scalpel for analysis.

Fine needle biopsies are usually used to determine whether a lump or “mass” is a cancer or something else. Since only a few cells are provided with a fine needle biopsy, it is not possible to be certain that a lump is not cancer, but it may be possible to prove the lump is cancer, or that it is something else.

Core needle biopsies are used when it is necessary to see the cells and how the cells are arranged, in order to make a diagnosis. Liver and kidney biopsies are usually core biopsies. In order to tell the cause of a patient’s kidney disease, or whether a liver transplant is being rejected, it is often necessary to biopsy the organ in question.

Open biopsies, or wedge biopsies, are usually done when needle biopsies are unsafe because of the risk of bleeding. Since the needles are small, any bleeding will almost always stop on its own after a needle biopsy. However, in a patient who has an abnormal tendency to bleed, a needle biopsy may not be safe; therefore, these patients need open biopsies. During an open biopsy the surgeon can use electrocautery and sutures to stop bleeding after the biopsy is taken.

— C —


An immunosuppressive drug used with other immunosuppressants to prevent the rejection of the transplanted organ. Also known by its chemical name, myophenolate mofetil.


A term meaning that one organism is made up of cells with more than one genetic background. All transplant patients are chimera's since they have cells from another person living within them.


Cholangitis is a bacterial infection in the bile duct. The symptoms and signs can include fever, elevation in bilirubin level, jaundice, chills, confusion, low blood pressure, elevations in liver enzymes, especially alkaline phosphatase. In general, something must be abnormal for cholangitis to occur: either there is some sort of obstruction to bile flow, such as a gall stone lodged in the duct, or scarring of the duct due to an inflammatory disease (e.g. sclerosing cholangitis), or some other sort of blockage, or the biliary anatomy is abnormal due to previous surgery. Patients that have abnormal biliary anatomy because they have had a porto-enterostomy (Kasai) or an operation that includes a roux-en-y reconstruction of the bile duct can have cholangitis for no good reason. However, in patients that have had a Kasai operation, recurrent cholangitis is considered to be a sign of impending liver failure and is sometimes used as an indication for liver transplantation. The treatment is antibiotics, plus relief of the obstruction, if one exists.


Medication categorized as a resin which acts like a “sticky” substance that binds many other chemicals including metals, vitamins, and bile acids. For this last reason it is frequently used to treat itching in patients with liver disease.


Cholestasis is a non-specific term for a build up of bile in the liver. This can happen for many different reasons. At times the cholestasis is related to a transient injury of the liver and it will often go away on its own. It can also be caused by drugs, in which case it may go away if the drug is discontinued. Cholestasis can also be the result of liver diseases such as sclerosing cholangitis, biliary atresia, primary biliary cirrhosis, and others.


Cirrhosis is a process in the liver that is characterized on biopsy as having scarring and nodule formation. It is thought to occur following the death of many, many liver cells. A simplified explanation is that something hurts the cells of the liver, which then die, leaving a scarred liver. A liver with cirrhosis may be small and shrunken, as in the case of cirrhosis due to hepatitis or excessive alcohol, or it may be very much enlarged, as in the case of primary biliary cirrhosis and biliary atresia. In all cases it is nodular and firmer than it should be. Normal liver is very soft and spongy. A liver with cirrhosis is very firm and hard. The exact cause of cirrhosis is not known.

clotting studies

Clotting studies are laboratory measurements of the body’s ability to clot. Examples include prothrombin time (PT), partial thromboplastin time (PTT), platelet count, and bleeding time. Each measurement looks at particular factors that are necessary in order for one to have a normal ability to clot.


Describes a condition present from birth. Congenital malformations include all disorders present from birth whether they are inherited or caused by environmental factors.

costal margin

Refers to the lower edge of the rib cage.


A drug, derived from a fungus, that inhibits the body’s immune responses. It is a standard drug for patients with organ transplants and is also used in some autoimmune diseases. Most organ recipients are kept on cyclosporine, or a similar drug called “tacrolimus,” for as long as they have a functioning organ transplant.

— D —


Decompensation means simply that a process that was formally stable has become unstable leading to failure. For example, a person who develops lung disease will begin to breath deeper and more quickly. They then are said to have “compensated” lung disease. However, if the lung disease gets bad enough, the person will not be able to breath fast enough and deeply enough without tiring. When this happens, the person is said to have “decompensated” lung disease.


A drug that causes the body to excrete sodium (salt). These drugs work by making the kidneys produce more urine, hence more salt is lost.

— E —

esophageal varices

Esophageal varices are enlarged veins in the esophagus. The esophagus is the muscular tube that connects the back of your throat to your stomach. It runs down the chest between the two lungs, behind the heart. Varices usually develop because of a build up in pressure in the veins leading to the liver. This problem, called “portal hypertension,” occurs in patients with liver disease. The increased pressure in the veins leading to the liver causes blood to try to find a way back to the heart other than through the liver. There are several channels that allow blood to do this, but ordinarily only a tiny amount of blood is going through these channels. When portal hypertension occurs, these channels, called “collateral circulation,” become swollen with blood. Esophageal varices and hemorrhoids are examples of these collaterals. Esophageal varices can burst spontaneously and lead to massive bleeding which may be apparent because the patient vomits blood or begins to have bloody bowel movements.

— F —

fatty liver

This is just what it sounds like: fat in the liver. It tends to occur in people that are overweight. Another term used is steatosis. Non-alcoholic steatohepatitis (NASH) is a problem that has been recently identified and written about in medical literature. It seems to be an advanced form of fatty liver. The significance and prognosis of NASH has not been defined well yet. Fatty liver will often go away with dietary modifications. Livers that are fatty may function normally, but for reasons that are unclear they make very poor transplant grafts. Fatty livers often do not work following the period of cold time associated with a transplant, therefore if a liver is extremely fatty it is not used for transplantation.

failure to thrive


Refers to the presence of scar tissue or collagen fibers in any tissue. In the liver, fibrosis or scarring of the liver damages the architecture and thus the functionality of the organ. Fibrosis, combined with the liver’s ability to regenerate, causes cirrhosis (regeneration within the scar tissue).

— G —



A tissue or organ that is removed and placed somewhere else. If the graft is from one person to themselves (for example, a hair transplant for bald men where their own hair is moved from the back of the head to the top), it is called an “autograft.” If the graft is between identical twins, it is called an “isograft” (this kind of graft is not rejected). If the graft is between members of the same species (for example, between father and son), the graft is called an “allograft.” If the graft is between different species (for example, a heart valve graft from a pig to a human), it is called a “xenograft” (pronounced ZEE-no-graft).

— H —


Enlargement of the liver to such an extent that it can be felt below the ribs.


The study of the structure of living tissue. For example, the "histology" of a tumor is determined by a biopsy of the tumor which is looked at under a microscope.


Hyperlipidemia means that there are excess levels of fats in the blood. These fats can be triglycerides, or cholesterol. Hyperlipidemia is often associated with increased risk of heart disease and strokes. There are genetic disorders that predispose to hyperlipidemia. Hyperlipidemia can also be caused by some medications including prednisone and others.

— I —


A technical term for jaundice.

immune system

The cells and proteins in the body that respond to infection and fight it off.


Anything that inhibits or weakens the immune system. Immunosuppressants can be drugs like prednisone and cyclosporine or can be diseases like cancer and AIDS.


A drug that suppresses the immune system by inhibiting cells that divide rapidly.


Anything that invades the body and reproduces. Infections can be bacteria, protozoa, fungi, or viruses. Bacteria and fungi are one celled creatures that cause many infections including strep throat, bladder infections, and some lung infections. Fungi cause “athlete’s foot” and thrush, an infection in the mouth. Protozoa are small organisms with many cells that can cause infections in the guts or in the lungs. Most healthy people do not get protozoal infections, but people with suppressed immune systems can. Viruses are not really organisms; they are tiny particles that can live only inside another cell. They reproduce by taking over a cell and causing that cell to make more virus particles, rather than doing what the cell is supposed to do. Viruses cause most colds and flu cases.


Within the blood stream.

— J —


Yellowish discoloration of all the tissues in the body, including the white of the eyes and the skin, that occurs when the blood contains abnormal amounts of the pigment bilirubin, which is normally excreted in the bile.

— K —

Kasai procedure

— L —

No terms in glossary.

— M —


Malabsorption is a problem with absorbing nutrients from the intestines. Malabsorption can happen for a variety of reasons including diseases of the bowels that impair absorption. Another example is pernicious anemia, a disease of the stomach that results in impairment of vitamin B12 absorption. Some vitamins (A, D, E, and K) require bile for absorption. In patients with liver diseases that lead to insufficient bile production, absorption of these vitamins is often impaired.


The way in which chemicals in the body are changed by the body. Poisons and toxins are disposed of by metabolism. Nutrients are used to build cells by metabolism.

milk thistle

Milk thistle is an herb that is said to be good for people with liver problems. It is thought that the active component in the herb is a substance named silymarin. Silymarin has been studied scientifically many times and to date no evidence has appeared that it has an important beneficial effect.

— N —

No terms in glossary.

— O —


A doctor that specializes in eyes.


OKT3 is a monoclonal antibody. Antibodies are proteins that are made by the immune system to fight infections. Antibodies usually attach to the surface of cells in the body and can cause the cell to die by a variety of mechanisms. Monoclonal antibodies are antibodies that are all exactly the same. They are made by taking the cell from an animal that makes antibodies and fusing that cell with a cancer cell from the same species of animal. This results in a cell that will live forever and make lots and lots of the same antibody. Most monoclonal antibodies are made in mice. 

The OKT3 monoclonal antibody binds to a protein on the surface of T cells called CD3. When this happens, the cell doesn't die, but it "activates" as if it had encountered a germ to fight against. The cell then secretes a number of chemicals into the blood and becomes dormant for a period of days. These chemicals tend to make the person receiving the antibody sick as if they have a bad infection: fever, headache, joint aches, nausea, diarrhea, muscle pain. Generally OKT3 is given either at the time of a transplant to prevent rejection from occurring, or to patients that have received a transplant and later developed rejection. OKT3 is very effective in both settings, but the side effects are very bothersome to the patient for the first 3-4 days.

— P —


The study of disease. Pathologists tend not to work with living patients, but with specimens of tissue or blood which are analyzed in order to provide information that will benefit the patient. Pathologists oversee the labs where blood tests are run and look at specimens from biopsies under microscopes to diagnose diseases like cancer. Pathologists also do autopsies on cadavers to find the cause of death.


Medication derived from a barbiturate which acts in the nerve cells of the nervous system. It is broken down and metabolized in the liver creating an increase in several enzymes that handle other medications or chemical substances. Even though it’s a sedative and anti-seizure medication, it was used in the past as a way to try to enhance the excretion of bile. Because of those ‘metabolic’ characteristics, it also alters the way the liver handles many other medications.

prophylactic antibiotics

Antibiotics prescribed or used to prevent certain specific infections.

portal hypertension

Portal hypertension is high pressure in the portal system. The portal system is made up of the veins that collect blood from the stomach, bowels, pancreas, and spleen. These veins come together and make up the portal vein which leads to the liver. When the liver is diseased, the blood cannot get through the liver very easily, so the pressure in the portal vein increases. This causes a number of problems including an enlarged spleen (splenomegaly), the collection of fluid in the abdomen (ascites), and a tendency to bleed from enlarged veins in the stomach and esophagus (varices).

primary biliary cirrhosis

A disease of the liver that leads to liver failure. It is more common in women than men and is thought to have an autoimmune cause, meaning that the body's own immune system damages the liver.


A technical term for itching.


PTLD stands for post transplant lymphoproliferative disease. This is a problem that occurs in transplant patients and is believed to be caused by an interaction between immunosuppression medications and a chronic viral infection called EBV (Epstein Barr Virus). PTLD occurs in a small percentage of transplanted patients and can progress to lymphoma, a cancer of the blood cells. PTLD can sometimes be treated by decreasing or stopping the immunosuppression medications.

— Q —

No terms in glossary.

— R —


When the body fights against a tissue or organ as if it were infected or damaged. This process usually results in damage to that organ or tissue.


A disease of weak bones caused by not getting enough vitamin D. Patients with liver disease can get rickets because their liver may not make enough bile, which is necessary to absorb vitamin D. Patients with kidney disease can get rickets because vitamin D is activated in the kidneys.

— S —

secondary biliary cirrhosis

Liver disease due to chronic obstruction of the bile duct. The bile duct can be obstructed by many different things including: Gall stones that migrate out of the gall bladder and get lodged in the bile duct. A tumor of the bile duct or a nearby structure like the duodenum (first portion of the small intestine). Inflammation (swelling) of the pancreas.


Organ that belongs to the Reticulo-endothelial, Hematological and Immune Systems. Localized in the abdomen, opposite the liver, under the rib cage on the left side of the abdomen. The spleen removes old or used and deformed blood cells including red cells, white cells, and platelets and generates a type of white cells, called “lymphocytes” which are responsible for the production of antibodies. The spleen is connected to the Portal System which explains why it becomes larger when blood gets congested in the portal vein in the presence of cirrhosis or a clot.


Splenomegaly is an enlarged spleen. The spleen is located on the left side of the abdomen just beneath the diaphragm. If you place your left palm flat on your abdomen with the middle finger touching the umbilicus and pointing to your right hip, the heel of your palm is approximately in the spot where your spleen is. Splenomegaly occurs when the spleen has a disease, or when portal hypertension develops due to liver disease. Splenomegaly often occurs during the disease mononucleosis (called the “kissing disease”).

Splenomegaly can cause a decrease in one’s platelet count. Platelets are little cells that circulate in the blood just like red blood cells that carry oxygen and white blood cells that fight infection. Platelets plug up holes in blood vessels and form a plug so that bleeding stops. When you cut your finger, the bleeding stops because platelets have plugged up the holes in all the blood vessels that were cut. In patients with splenomegaly, the platelets get trapped in the spleen more than they should, leading to a decreased number of platelets in the blood stream.


Refers to things that are not moving or changing.


A hormone that controls metabolism in the body.

— T —


A drug, derived from a fungus, that inhibits the body’s immune responses. It is a standard drug for patients with organ transplants. Most organ recipients are kept on either tacrolimus or a similar drug called “cyclosporine” for as long as they have a functioning organ transplant.

T cells

T cells are cells that fight infection. T cells are a kind of lymphocytes. Lymphocytes are white blood cells that are involved in acquired immunity. Acquired immunity is the ability to fight off something that we were exposed to in the past. This is how vaccines work: once the immune system is exposed to a particular structure of an organism, it will respond vigorously the next that that organism is encountered, usually fighting the organism off before it makes one sick. T cells are lymphocytes that originally developed in the thymus, an organ in the chest in front of the heart. The other lymphocytes are B cells which develop in the spleen.

— U —

No terms in glossary.

— V —

No terms in glossary.

— W —


To reduce slowly.

— X —

No terms in glossary.

— Y —

No terms in glossary.

— Z —

No terms in glossary.

end faq