Natural History of
HCV
Hepatitis C is often asymptomatic. Most
symptoms begin only when irreversible liver damage (cirrhosis)
is established. The best outcomes for HCV patients depend upon early
recognition of the infection. Any person with risk
factors should be screened for HCV. Multiple studies have shown that
earlier treatment of patients who have chronic liver disease associated
with hepatitis C results in improved outcomes.
Chronic infection with HCV is an
epidemic within the United States. A majority of patients who acquire
hepatitis C will progress to some form of chronic liver disease. Recent
evidence published in the New England Journal of Medicine indicates some
patients may have a long course in which the disease does not causes
significant damage to the liver. However, it is difficult to identify
those patients since their clinical characteristics are unknown. There are
no blood or radiologic tests which identify this group of HCV patients.
Most patients who acquire HCV infection
are not aware that they have become infected. Acute infection with HCV is
usually associated with flu like symptoms and not jaundice (turning
yellow). As a result, patients may have the infection for years before
being identified. Most patients are identified during routine physical
exam or blood donations. Abnormal liver function tests are identified
during these evaluations. When abnormal liver function tests or a history
of risk factors are identified, further testing is recommended.
Once the infection has been established,
the liver experiences inflammation which over 20 years may result in
cirrhosis. It is thought that 85 % patients infected with HCV will develop
some form of chronic inflammation of the liver. Of these patients, about
20 % will develop cirrhosis of the liver after about 20 years of
infection. Some patient populations seem to tolerate the infection better
than others. These patients are under investigation to identify the means
by which this is accomplished.
The primary goal for patients with HCV
is early institution of therapy to prevent the development of cirrhosis.
Once cirrhosis is present, the response rates for treatment decrease
significantly. In addition, the possibilities of developing complications
from cirrhosis (such as hepatocellular carcinoma and portal hypertension)
increase rapidly.
Patients with Hepatitis C infection may
have normal, fluctuating or persistently elevated ALT
levels. It is important that these liver
function test abnormalities be present for at least 6 months. However,
if an individual has recently had been identified as having elevated liver
function test, and has one or more of the above risk
factors, an immediate test for the Hepatitis C antibody test (EIA) is
appropriate.
Hepatitis C is a heterogeneous
infection. Its interrelationship with the human immune system is variable
and difficult to correlate. However, some trends have been identified. In
some patients serious liver disease may occur within the first several
years. However, in most patients chronic liver disease requires infection
for 20 to 30 years. When acquired in older age, the disease may progress
more rapidly. Ingestion of alcohol has been clearly associated with an
increased rate of hepatic inflammation. HCV patients who drink often have
an acceleration of their disease.
Associated Diseases
Hepatitis C is thought to be associate
with multiple other diseases:
Lichen
planus.
Mixed
cryoglobulinemia
Porphyria cutanea
tarda (PCT).
Mooren's corneal
ulcers.
Clinical Presentation
The most common presentation of
hepatitis C is a patient with no complaints. Many patients, especially
when questioned closely, report a history of fatigue and malaise.
Intermittent right upper quadrant abdominal pain may also be present.
However, the typical patient with
hepatitis C will be asymptomatic and have normal, intermittently elevated,
or persistently elevated liver function test.
The primary problem for patients with
HCV and their physicians is communication regarding possible risk factors
for acquisition of the HCV virus. If you have a history of any of the risk
factors, please contact your physician.
Diagnosis of Hepatitis C
The initial test for hepatitis C is the
enzyme-linked immunoassay. This is also known as the enzyme immunoassay (EIA).
This test looks for the antibody to HCV in the blood. Over the past 10
years three generations of EIA antibody tests for hepatitis C has been
developed. The most commonly used today, EIA 3, is 95 percent specific and
sensitive for hepatitis C. However, this test, even when positive, needs
to be confirmed with a polymerase chain reaction (PCR)
to evaluate the presence of HCV virus. If the PCR is positive, further
blood testing for the viral load (amount of virus in one milliliter of
serum) and the genotype (type of HCV
present) can be performed.