Glossary
Acute Hepatitis Infection: A new, suddenly
occurring infection. It occurs with a person’s first exposure
to the hepatitis B virus.
Adefovir dipivoxil (Hepsera): An oral nucleoside
analogue drug that interferes with the replication of the hepatitis
B virus (e.g. it can slow down or stop the virus from reproducing).
It was approved for chronic hepatitis B in September 2002.
Albumin: A protein made in the liver that assists
in maintaining blood volume in the arteries and veins. If the
liver is damaged, then the albumin can drop to very low levels,
which may cause fluid to leak into the tissues from the blood
vessels, resulting in edema or swelling. In acute liver failure,
there is an accumulation of fluid in the abdomen that is known
as "ascites".
Alpha-fetoprotein (AFP): A protein secreted
into the blood during pregnancy or when cancer cells are present.
Increased levels may indicate the development of liver cancer,
which is why the simple AFP blood test is included in the regular
monitoring of those which chronic HBV.
Antibody: A protein molecule produced by the
immune system in response to a foreign body, such as the hepatitis
B virus. Antibodies can be produced in response to a vaccine
or to a natural infection. They circulate in the blood to protect
against future infections.
Anti-HCV (antibody to hepatitis C virus):
The antibody produced against the hepatitis C virus (HCV). Its
presence in the bloodstream often indicates HCV infection. This
antibody has not been shown to protect people against hepatitis
C.
Antigen: A protein on the surface of a virus,
bacteria or cell that can stimulate the immune system to produce
antibodies as a defense mechanism.
Ascites: A large, abnormal accumulation of
fluid in the abdomen that can occur due to liver failure, cirrhosis
and liver cancer. This condition requires immediate medical attention.
Asymptomatic: Refers to infection or disease
without signs of illness. Many patients with hepatitis B or C
do not have any symptoms during a new or chronic infection; they
are considered to be asymptomatic.
Bilirubin: The liver usually clears this end
product of hemoglobin (the portion of the red blood cell that
carries oxygen in the blood) when it normally breaks down. If
the liver is damaged and bilirubin accumulates in the blood,
a person can become jaundiced (yellowed eyes and skin).
Bloodborne Pathogens: Substances present in
the blood that can cause infection or disease. Hepatitis B and
hepatitis C viruses are bloodborne pathogens since they are spread
through blood and can cause a liver infection.
Carcinoma: A new growth or malignant tumor
that can occur throughout the body (e.g. hepatocellular carcinoma
refers to liver cancer).
Centers for Disease Control and Prevention (CDC): This
federal organization is concerned with the prevention and control
of communicable diseases such as hepatitis B and C. It conducts
extensive research and provides information about public health
topics.
Chronic Hepatitis B Infection: A patient who
tests positive for the hepatitis B virus for more than 6 months
is considered to have a chronic hepatitis B infection.
Cirrhosis: A serious liver condition characterized
by irreversible scarring of the liver that can lead to liver
failure and death. Alcohol and chronic viral hepatitis (such
as chronic hepatitis B and C) can cause continuous inflammation
of the liver, which can lead to excess scar formation or fibrosis.
Scarring results in the loss of liver cells and impairs liver
function.
Clinical Trials: Carefully controlled studies
that are conducted in humans who volunteer to test the effectiveness
and safety of new drugs, medical products or techniques. All
drugs in the United States undergo three phases of clinical trials
before being approved for general use.
Clotting Factors: Proteins made in the liver
that are important in maintaining normal blood clotting. Disruption
in the blood's ability to clot may indicate that the liver is
not creating enough clotting factors. A severe shortage in clotting
factors may indicate that a liver transplant is needed.
Complete Blood Count (CBC): A test that measures
the number of red blood cells, white blood cells, the amount
of hemoglobin, hematocrit, and platelets. Low white blood cell
and platelet counts may indicate liver scarring.
Complications: New medical problems that arise
while treating existing ones.
DNA Polymerase: An enzyme essential to the
replication of the hepatitis B virus. Most of the current antiviral
drugs used against HBV interfere with the DNA polymerase in order
to stop the virus from reproducing.
Decompensated Cirrhosis: A late-stage cirrhosis
accompanied by abnormal blood tests and other complications.
At this stage of the disease, evaluation for liver transplant
becomes an option.
E-Antibody (HBeAb or anti-HBe): Produced by
the immune system temporarily during acute HBV infection or consistently
during or after a burst in viral replication. Spontaneous conversion
from e-antigen to e-antibody (a change known as "seroconversion")
is a predictor of long-term clearance of HBV in patients undergoing
antiviral therapy.
Encephalopathy: Serious brain function abnormalities
experienced by some patients with advanced liver disease. Symptoms
most commonly include confusion, disorientation, insomnia, and
may progress to a coma.
Entecavir: An oral nucloeside analogue drug
that interferes with the replication of the hepatitis B virus
(e.g. it can slow down or stop the virus from reproducing). It
was the third oral drug approved for chronic hepatitis B in April
2005.
Enzymes: Naturally occurring chemical substances
in the human body that help a chemical reaction take place.
Epidemiology: A field of medical science that
studies the incidence, distribution, and control of disease in
a population. This information is often used to determine causes
and methods of controlling diseases.
False-Positive: A test result that mistakenly
gives a positive reading.
Fatty Liver: Refers to a condition where fat
accumulates in liver cells. This accumulation of fat does not
generally cause liver damage, but it needs to be monitored. It
is detected by liver biopsy.
Fibrosis (hepatic): Growth of fibrous tissue
in the liver where there is usually liver cell damage or destruction.
Fibrosis can lead to cirrhosis, an even more serious liver disease.
Food and Drug Administration (FDA): A federal
organization charged with protecting the public health. It establishes
safety and effectiveness guidelines for healthcare products such
as the drugs that are used to treat hepatitis B and C.
Gastroenterology: The field of medicine that
focuses on the function and disorders of the GI system, which
includes the esophagus, stomach, pancreas, intestines, and liver.
Genome: Refers to the genetic material of
an organism such as a human or a virus.
Genotype: A pattern of genetic information
that is unique to an individual or group. The hepatitis B virus
has a pattern of genetic information unique to itself. Doctors
may determine the genotype to help decide the best treatment.
Currently, there are seven known genotypes for hepatitis B; however,
its significance is not well established for clinical use. Hepatitis
C treatment can be based on genotype.
Hepatitis: Refers to “inflammation of the
liver”, which can be caused by many things such as viruses, bacterial
infections, trauma, adverse drug reactions, or alcoholism. Inflammation
of the liver caused by viruses is called “viral hepatitis”. There
are many different viruses that attack the liver:
Hepatitis A: Formerly called “infectious hepatitis”,
it is caused by the hepatitis A virus (HAV) and is an acute infection.
There is no chronic infection. Most patients recover completely
within 6 to 10 weeks. Hepatitis A is spread mainly via feces
and contaminated food and water. There is a safe vaccine for
HAV.
Hepatitis B: Formerly called “serum hepatitis”,
it is caused by the hepatitis B virus (HBV). Approximately 10%
of infected adults progress to chronic hepatitis B; 90% of newborns
born to HBV infected women develop chronic infections; and young
children have a 30-50% chance of developing a chronic infection.
It is spread primarily through blood, unprotected sex, shared
needles, and from an infected mother to her newborn during the
delivery process. There is a safe vaccine for HBV.
Hepatitis C: Formerly known as “non-A, non-B
hepatitis”, it is caused by the hepatitis C virus (HCV). Approximately
85% of infected adults will develop chronic hepatitis C infections.
It is spread through infected blood, primarily in those who use
illicit street drugs and those who received blood transfusions
prior to1992 (the first year that a blood test for HCV became
available for screening the blood supply). There is no vaccine.
Hepatitis D: Known as “delta hepatitis”, it
is caused by the hepatitis D virus (HDV). This virus can only
co-infect patients who are already infected with hepatitis B.
Hepatitis D infection is rare in the United States. It occurs
primarily in recipients of multiple blood transfusions, including
patients with hemophilia or those undergoing renal dialysis,
and among people who share contaminated needles. There is no
vaccine.
Hepatitis E: Also referred to as “enterically
transmitted non-A, non-B hepatitis”, it is caused by the hepatitis
E virus (HEV). It is spread through fecal contamination of water;
occurs primarily in developing countries; and is found rarely
in the United States. Hepatitis E infection results in an acute
infection much like hepatitis A; it does not cause chronic infection.
There is no vaccine.
Hepatitis F: Only a handful of cases have been
reported from France with subsequent experimental transmission
to primates. The virology, epidemiology and clinical importance
of the hepatitis F virus are uncertain. There is no commercial
test nor is there a vaccine.
Hepatitis G: The hepatitis G virus (also called
hepatitis GB virus or HGBV-C) is a distant relative of the hepatitis
C virus. It appears to be transmitted through transfusions (one
to two percent of US blood donors have HGV RNA detectable in
their serum). Its role in acute and chronic hepatitis remains
unclear. Recent studies suggest that the virus may not even replicate
in the liver. At the present time, HGV does not appear to be
an important cause of clinical liver disease. There is no commercial
test nor is there a vaccine.
Hepatitis B Blood Panel: There are three common
hepatitis B tests that make up the Hepatitis B Blood Panel. This
is a simple test that requires only one blood sample, which can
be obtained during an office visit to the doctor.
1. Hepatitis
B Surface Antigen (HBsAg): The surface protein of
the hepatitis B virus that is used as a marker to detect infection.
If this blood test is positive, then the hepatitis B virus
is present.
2. Hepatitis
B Surface Antibody (HBsAb or anti-HBs): The antibody
formed in response to the surface protein of the hepatitis
B virus. It can be produced in response to vaccination or recovery
from an actual hepatitis B infection. If this test is positive,
then the immune system has successfully developed a protective
antibody against the hepatitis B virus that provides long-term
immunity.
3. Hepatitis
B Core Antibody (HBcAb or anti-HBc): This antibody
only refers to a part of the virus itself; it does not provide
any protection or immunity against HBV. This test is often
used by blood banks to screen blood donations. A positive test
indicates a person may have been exposed to the hepatitis B
virus, but the result can only be confirmed in relationship
to the above two tests.
HBeAg: A marker of a high degree of HBV infectivity,
it correlates with a high level of HBV replication. It is primarily
used to help determine the clinical management of patients with
chronic HBV infection.
Hepatitis B Immune Globulin (HBIG): A medication
that is given as a “post-exposure” treatment to prevent hepatitis
B. This means that HBIG is given after a person has been exposed
to potentially infected blood or infected bodily fluids, which
can include but is not limited to - contact with blood or through
a needlestick, infants born to infected women, and through sexual
contact or close household contact with an infected person. HBIG
is often used as a post-liver transplant treatment.
HBV-DNA: A marker of viral replication. It
correlates well with infectivity. It is used to assess and monitor
the treatment of patients with chronic HBV infection.
Hepatocellular Carcinoma (HCC): A malignant
tumor of the liver, otherwise known as liver cancer. Chronic
hepatitis B and C infections may increase the risk of developing
liver cancer.
Hepatocyte: A liver cell.
Hepatologist: A doctor who specializes in
the study and treatment of liver disease. Ideally, patients with
chronic hepatitis B or C should see a “hepatologist”.
Hepatology: The field of medicine that focuses
on diseases of the liver. It is a sub-specialty within gastroenterology.
Histology: The field of medicine that studies
tissue under the microscope. Histological evaluations of liver
biopsy samples are helpful in the diagnosis and monitoring of
possible liver damage in chronic HBV and HCV carriers.
IgG anti-HBc: A subclass of the hepatitis B
core antibody (HBcAb or anti-HBc) is a marker of past or current
infection with HBV. If it and HBsAg are both positive (in the
absence of IgM anti-HBc), this indicates chronic HBV infection.
IgM anti-HBc: A subclass of the hepatitis B
core antibody (HBcAb or anti-HBc). Positivity indicates recent
infection with HBV (less than 6 months). Its presence indicates
acute infection.
Immune System: The body’s defense system against
invasion by foreign bodies such as bacteria, viruses, fungi,
parasites, and malignant cells.
Immunology: The branch of medicine that studies
the immune system, immunity, and allergies.
Infection: The results of the presence of
harmful microorganisms in the body. Infections can be acute (sudden)
or chronic (persistent).
Injection: A method of administering drugs
or nutrients into the body using a needle.
- Intramuscular (IM): into muscle tissue.
- Intravenous (IV): into a vein.
- Subcutaneous (SQ): beneath the skin.
Interferon: A protein that is produced by the
body to protect against infection. Many different cells including
liver cells produce natural interferon. Interferon also can be
manufactured artificially through biotechnology for the treatment
of chronic hepatitis B and C.
Interferon Alpha-2b (Intron A): A drug that
mimics naturally occurring “interferon”, which is an infection-fighting
immune substance produced by the body. It is self-administered
at least three times a week by injection. This was the first
drug approved for chronic hepatitis B in 1991. Available for
both adults and children greater than 2 years old.
Investigational Drug: A new drug that is undergoing
clinical trials to prove its effectiveness and safety (see clinical
trials).
Jaundice: A condition characterized by yellowing
of the skin and eyes. Jaundice is a symptom of many disorders,
which can include viral hepatitis, alcoholism, poisoning, and
abnormal breakdown of red blood cells or gallbladder disease.
This symptom requires immediate medical attention.
Lamivudine (Epivir-HBV, Zeffix, Heptodin): An
oral nucleoside analogue drug that interferes with the replication
of the hepatitis B virus (e.g. it can slow down or stop the virus
from reproducing). It was the second drug approved for chronic
hepatitis B in December 1998. Available for both adults and children.
Liver: The largest glandular organ in the
body. The liver has many functions that include, but are not
limited to the production of protein and cholesterol, the production
of bile and clotting factors, the storage of sugar in the form
of glycogen, and the breakdown of carbohydrates, fats, and proteins.
The liver also breaks down and excretes many medications.
Liver Biopsy: The removal of a small piece
of tissue from the liver using a special needle. The tissue is
examined under a microscope to look for the presence of inflammation
or liver damage (see histology).
Liver Enzymes: Proteins that catalyze chemical
reactions needed for bodily functions. Levels of certain enzymes,
such as ALT and AST are higher when the liver is injured, as
they leak into the bloodstream when the cell is injured or destroyed.
Liver Function Tests (LFT’s): Refers to a
group of blood tests used to evaluate the function of the liver.
The tests can be used to diagnose and monitor chronic viral hepatitis
as well as other liver diseases. The two most common tests include
the following liver enzymes:
- Aspartate Aminotransferase (AST): An enzyme
that is released into the blood by the liver and other tissues
or organs. It is generally used as a marker for liver or biliary
damage.
- Alanine Aminotransferase (ALT): An enzyme
that is released into the blood by damaged liver cell. It is
used as a marker for liver cell damage. The ALT test is considered
to be a more accurate reflection of liver inflammation than
AST because other organs such as the heart can also produce
AST. (e.g. the level of AST will increase on a blood test during
a heart attack). ALT levels are included in the regular monitoring
of all chronic hepatitis B patients; this test can also useful
in deciding whether a patient would benefit from therapy or
evaluating the effectiveness of an ongoing treatment.
Needlestick: Refers to an accidental puncture
of the skin while handling hypodermic needles or syringes. This
is most common among health care providers such as physicians,
nurses, and emergency response personnel.
Non-Responders: Patients who do not respond
to therapy or a vaccine within a specific period.
Patient Compliance: Patients who correctly
follow all the instructions about a course of therapy as directed
by their physician are considered to be “compliant” with a treatment
protocol (see protocol below).
PCR (polymerase chain reaction): A highly
sophisticated scientific method of detecting the presence of
hepatitis B virus DNA or hepatitis C virus RNA in the blood.
This test can be conducted on the same sample of blood obtained
with the hepatitis B panel of blood tests; no extra doctor’s
visit is needed.
Peg Interferon Alfa-2a (Pegasys): A pegylated
interferon drug that mimics naturally occurring “interferon”,
which is an infection-fighting immune substance produced by the
body. It is self-administered once a week by injection and seems
to have fewer side effects than the interferon alpha. Approved
for treatment of chronic hepatitis B in May 2005.
Percutaneous: Passage or absorption of substances
into the body through unbroken skin.
Perinatal Transmission (vertical transmission): Transmission
of an infectious disease, such as hepatitis B, from mother to
newborn. All pregnant women should be tested for hepatitis B
since newborns have a 90% chance of becoming chronically infected
if they do not receive the first dose of hepatitis B vaccine
and a single dose of HBIG within 12 hours after delivery. The
infant will also need additional doses of hepatitis B vaccine
at one and six months of age to ensure a complete immune response.
Persistent: A disease or other medical condition
that returns or continues over a long time.
Platelets: Cells that are produced in the
bone marrow. Platelets control bleeding by causing the blood
to clot. The liver produces the clotting factors involved in
this process. If the liver is damaged, then clotting will also
be impaired.
Post-Transfusion Hepatitis: Liver inflammation,
or hepatitis, that occurs when the body reacts unfavorably to
a blood transfusion. This is now rare in the United States due
to careful blood screening procedures.
Protein: A substance made of a string of amino
acids. Proteins are the “building blocks” of the human body.
Protocol: A detailed plan of a scientific
experiment or medical treatment. A specific step-by-step procedure
is used in clinical trials to test new drugs and treatments for
diseases such as chronic hepatitis B.
Recombinant DNA: Genetic material that has
been altered and recombined in the laboratory by cutting up DNA
molecules and splicing together specific DNA fragments. Many
drugs, including the hepatitis B vaccines, are produced using
recombinant DNA methods.
Reconstitution: The process of adding liquid
to a dry powder to make a new solution. Prescription drugs that
are given by injection are often provided as a dry powder, which
must be reconstituted (e.g. liquid must be added) before it can
be used.
Recreational Drugs (illicit drug use): Illegal
drugs, such as marijuana, crack, cocaine, and heroin. People
who use these drugs have a much greater risk of acquiring a hepatitis
B or C infection as a result of sharing needles or engaging in
other behaviors that increase their risk of exposure to infected
blood.
Relapse: The return (or recurrence) of symptoms
of a disease after a period of improvement.
Remission: A period of time during which all
or some of the symptoms of a disease have disappeared or decreased
in severity. Remission may occur spontaneously or as a result
of medical treatment.
Retreatment: Treatment that is restarted after
a patient has suffered a relapse or has not responded to treatment
the first time.
Risk Factors: Refers to behaviors and conditions
that increase the possibility of an individual developing a disease.
Smoking is a risk factor for lung cancer. Jobs that expose a
person to blood or the use of illegal drugs are risk factors
for acquiring a hepatitis B or C infection.
Screening: Testing blood samples or blood
donations for the presence of disease. Before blood donations
are accepted, they are screened for hepatitis B, hepatitis C,
and HIV/AIDS and other bloodborne pathogens.
Self-Administration: Therapy, such as interferon
injections, that patients give to themselves rather than having
it done by a health care provider.
Seroconversion: A change in status from antigen
positive/antibody negative to antigen negative/antibody positive.
For example, seroconversion of e-antigen positive to e-antibody
positive indicates a significant decrease in the amount of hepatitis
B virus. Seroconversion of hepatitis B surface antigen positive/surface
antibody negative to surface antigen negative/surface antibody
positive connotes being "cured" of a chronic HBV infection
since the virus has been cleared from the liver and bloodstream.
Serology: Refers to the study of serum (the
clear portion of a body fluid) for its antibody content. When
a person is exposed to a microorganism, such as the hepatitis
B or C virus, the body produces specific antibodies against it.
In laboratory testing, the antibodies react with antigens in
specific ways that can be used to confirm the identity of the
microorganism, however, this test is not used to diagnose a current
infection.
Spleen: An organ located in the left upper
abdomen that removes old red blood cell and other blood cells
from circulation. The spleen can enlarge in a person who has
cirrhosis.
STD (sexually transmitted disease): A disease
that is transmitted through sexual contact.
Sustained Response: A response to therapy
that continues over a long time period. For example, a patient
treated for chronic hepatitis B or C who remains free of the
virus for at least 6 months after stopping treatment is considered
to have a sustained response to therapy.
Symptom: Any change in the body or its functions,
as perceived by the patient, which could indicate the presence
of disease.
T-Cells: A type of white blood cells that
are involved in rejecting foreign tissue, regulating immunity,
and controlling the production of antibodies to fight infection.
Therapy: Treatment of a disease.
Transaminases: Refers to SGOT or SGPT, which
are older terms for the ALT and AST amino transferases (see liver
function tests).
Transfusion: The introduction of whole blood
or components of blood (such as plasma, platelets) from one person
to another.
Transmission: The way or method by which a
disease can be spread.
Vaccine: A medication that stimulates the
production of antibodies to protect against a specific disease.
There is a hepatitis A vaccine, hepatitis B vaccine, and a combination
vaccine that provides protection against both hepatitis A and
B at the same time.
Variceal Bleeding: Abnormal bleeding from
ruptured blood vessels in the esophagus that results from severely
impaired blood flow through the liver. Patients with advanced
cirrhosis are at greatest risk for this complication. This is
a life-threatening emergency and requires immediate medical attention.
Viral hepatitis: Inflammation of the liver
caused by viruses that specifically attack the liver: hepatitis
A, B, C, D, E, F, and G viruses.
Viral Load: Measurement of the actual amount
of virus in the bloodstream such as hepatitis B and C.
Viremia: Refers to the presence or amount
of a given virus in the bloodstream.
Virus: A tiny microorganism, smaller than
bacteria, which can invade the body and cause disease. A virus
can reproduce itself exactly or mutate and make small changes.
The ability of a virus to change slightly in each infected person
is why treatment of viral diseases is so difficult.
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