It
is a clinical challenge treating patients with Hepatitis C (HCV),
which very often is found in asymtomatic patients donating blood
or patients incidentally found to have elevated liver enzymes
on routine blood tests. Some though may complain of fatique
or malaise.
Less than 15% of patients with chronic HCV clear the virus after
an acute infection and only about 1% do so after a chronic infection
has developed. Using the rule of 20’s, about 20% of chronic
HCV patients will develop cirrhosis in about 20 years. The risk
of liver cancer in HCV related cirrhosis is about 20%. In patients
receiving Interferon monotherapy there is a 20% chance of achieving
a sustained response.
HCV
is an RNA Virus that mutates frequently, which may explain
why the antibody tire appears late (4-6 weeks after the onset
of symptoms) and why there may not be complete immunity to
reinfection and this has made it difficult to develop a vaccine.
There are 6 major genotypes of the HCV. Genotypes 1a and 1b
are the most common in the U.S., and though these do not produce
as severe a liver disease as 2a they are more resistant to
alpha interferon therapy.
Third
generation EIAs are currently available and are highly sensitive
in making a diagnosis. A suspected false positive test should
be confirmed by an RIBA test, which is both sensitive and
specific. There are 2 assays to measure viral load: the PCR
and the branched DNA test. These detect the virus in a suspected
case of exposure before the patient develops antibodies or
symptoms.
HCV
is found mainly in the liver and blood. Body fluids such as
saliva, urine, semen and vaginal secretions have rarely been
shown to contain the virus and have not been shown to transmit
the virus. Sexual transmission is therefore rare and unlike
Hepatitis B, and if monogamous and heterosexual, no special
precautions are required. Most infection spread has been through
practices which include snorting cocaine, tattooing and from
blood transfusions. (prior to 1990) and dialysis machines.
Maternal fetal transmission occurs in about 5% of cases and
in about 30%, the source is undetected.
Therapy
is recommended for all patients with chronic HCV with raised
ALT levels, HCV RNA positivity and a liver biopsy showing
some degree of fibrosis and/or moderate to severe inflammation.
Therapy is not recommended for patients with advanced cirrhosis
or mild hepatitis with normal liver enzymes although the later
is debatable. Contraindications to therapy include severe
neuropsychiatric illness, bone marrow compromise or organ
transplant recipients (other than liver). The currently recommended
regimen is a combination of Interferon and Ribavirin for 24-48
weeks depending on the genotype and clinical response. Newer
therapies are being developed but until then HCV is the most
common reason for liver transplant (40%) and almost a billion
dollars is spent a year on the treatment of HCV. Early detection
and more aggressive therapy will hopefully bring this number
down.
-
Peter D'sa MD, Gastroenterologist
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