Causes:
Hepatitis B and C are the most
common causes of chronic hepatitis. Together they account for more than
75% of the cases in the world. Hepatitis B is far more common in China
and sub-Saharan Africa and among male homosexuals and IV drug users.
Chronic hepatitis C behaves
differently from hepatitis B. The disease is generally mild, with fatigue
being the main symptom. However, ten or more years later, the complications
of cirrhosis appear in some patients, sometimes unexpectedly. By contrast
with hepatitis B, the percentage of patients infected who develop cirrhosis
is much greater. While
primary liver cancer can
also develop from hepatitis C, it appears to be much less common than after
hepatitis B.
Autoimmune
hepatitis varies from mild to serious disease. The percentage of patients
who develop cirrhosis is high and it may appear early. Most of the patients
are young women but post menopausal women and males may get the disease.
Only a few cases of primary liver cancer have been reported with this disease.
Twenty-five percent of the cases of chronic hepatitis result from damage
to the liver by the immune system. The trigger for autoimmune chronic hepatitis
is unknown, but the damage to the liver is caused by the individual's lymphocytes
and by antibodies produced in the individual's own tissue. Autoimmune chronic
hepatitis is usually a progressive disease ending in cirrhosis.
Hepatitis
A and E (formerly called epidemic or enteric non-A, non-B) are rarely,
if ever, responsible for causes of chronic hepatitis.
Hepatitis D
infection needs the hepatitis B virus to multiply. Hepatitis D can cause
acute hepatitis in someone who is a carrier of the hepatitis B virus and can
cause acute hepatitis at the same time that the hepatitis B virus does. In
any event, the combination of hepatitis B and D is worse then hepatitis B
alone and is more likely to cause serious chronic hepatitis and cirrhosis.
IV drug users have a high incidence of hepatitis D.
Other Causes:
Viruses of the herpes family,
which cause cold sores, genital herpes, chicken pox, shingles and infectious
mononucleosis, can cause acute hepatitis, especially when the immune system
is not functioning properly. It is unlikely that they will produce chronic
hepatitis. Other viruses, as yet undiscovered, may be responsible for some
cases of chronic hepatitis.
Few medications still in use
and several that have been withdrawn from the market can also cause chronic
hepatitis. These include: isoniazid, used for tuberculosis; methyldopa,
used for hypertension; nitrofurantoin, used for urinary tract infections;
phenytoin, used for seizure disorders and selected other prescription medications.
These medications must be taken for long periods of time and the number
cases of chronic hepatitis produced by these medications is small.
Chronic hepatitis caused by
drugs is usually recognized early. Stopping the medicine before cirrhosis
has developed usually reverses the disease.
Inherited Disorders:
Some inherited disorders of
metabolism also can appear as chronic hepatitis. The most frequent of these
conditions is Wilson's Disease a familial disorder of copper metabolism.
Alpha-1 Antitrypsin Deficiency and tyrosinemia may appear as chronic hepatitis
although other features help in distinguishing these rare conditions from
those caused by viruses.
Signs and Symptoms:
-
Fatigue, mild discomfort in
the upper abdomen, loss of appetite and aching joints are the common symptoms
of chronic hepatitis.
-
Fatigue is by far the most common symptom and it
might be quite disabling. Often it gets worse as the day wears on. Some
patients, however, may have no symptoms. Others may have signs of liver
failure, inducing jaundice, abdominal swelling (due to fluid retention
called ascites), or coma, depending on the severity of the liver disease
and whether or not cirrhosis has developed.
-
Most complications are vague
and may be mistaken for other diseases or simply a consequence of aging.
Disorders of other organs like the thyroid, intestine, eyes, joints, blood,
spleen, kidneys and skin may occur in about 20% of patients depending on
the cause of the chronic hepatitis.
When the hepatitis is mild
and limited in extent, it is called chronic persistent hepatitis (CPH).
When it is more extensive and seems to be destroying the cells of the liver,
it is called chronic active hepatitis (CAH).
Treatment:
Interferon has been approved for the treatment of hepatitis B and C. The treatment
has been shown to reduce the inflammation and liver damage caused by the
virus in 25-30% of cases by eliminating the virus, thus reducing the development
of scar tissue and avoiding the development of cirrhosis.
In people treated with interferon
studies show that 50% will respond to treatment and 50% of those patients
will relapse when interferon is stopped. Research is going on to address
the relapse rate.
Additional clinical
trials are being conducted to identify the most effective dose and
duration of therapy with interferon. Studies are continuing in an attempt
to reduce the side effects of the medication that exists. These include
"flu like" symptoms, and less often, fever, depression, hair loss, nausea
and vomiting. Currently, the treatment consists of an injection three times
a week over a period of six months.
Blood tests are needed to monitor
progress during treatment and a liver biopsy (retrieving a small specimen
of the liver through a needle inserted into the liver) is an accepted procedure
prior to and following treatment.
Fifty percent of the patients
treated will experience remission of the disease. When the treatment is
stopped 50% will relapse. However, only about 20% of untreated patients
will go on to develop cirrhosis over a period of years. Research into the
management of those who relapse is ongoing.
Interferon does not seem to
work well in patients :
-
With
substance abuse (alcohol or illegal drugs),
-
Who
are not very sick,
-
Whose
test results are not very abnormal,
-
Whose
immune system is not functioning well because of AIDS,
-
With
hepatitis B who were infected from their mothers at birth,
-
Carriers who are no longer contagious or infectious,
-
With significant heart, lung or kidney diseases, or couples who are trying to conceive.
Knowing the cause of the disease
is helpful in estimating the prognosis.
Only a small percentage of
patients with chronic hepatitis B develop cirrhosis. In those patients,
cirrhosis develops early in the course of the disease with complications
appearing in the first few years. Chronic hepatitis often causes acute
hepatitis or flare-ups and periods with no signs. Scarring becomes more
extensive with each flare-up. Patients in the Orient have about a 15% chance
of developing primary liver cancer, usually after the age of 50 with men
more likely candidates than women. This complication is much less common
in the Western World.
The disease becomes life threatening
only after cirrhosis has developed. More than half of all patients live
at least 15 years from the time of the first diagnosis and this number
is continuously improving. Previously, prognosis was thought to depend
on what was found on liver biopsy. This is now only partly true. Prognosis
is worse and complications more numerous and severe if cirrhosis has already
developed. Much attention has been paid to the location and extent of the
inflammation of the liver.
Steroid therapy remains the
only useful treatment for autoimmune disease, but it may have to be given
for a lifetime and may also not prevent the ultimate development of cirrhosis.
Liver transplantation has become an accepted form of therapy when chronic hepatitis becomes life
threatening, usually as a result of complications of cirrhosis. Recurrence
of hepatitis C or autoimmune hepatitis does not seem to occur, but hepatitis
B, if virus is still present and the patient is contagious, will recur
in the new liver and often be acute. Attempts are being made to prevent
this recurrence.
The most important treatment
for hepatitis B is prevention. Hepatitis B vaccines should be given to
all who are exposed to this disease on a regular basis. All pregnant women
should be tested for hepatitis B. Carriers of hepatitis B, many of them
unaware that they are infected, can pass it on to their babies as well
as their sexual contacts. All newborns should be vaccinated against hepatitis
B. Three injections are needed to provide adequate immunity.
An important aspect of treatment
is supportive care. Diet should be well balanced. The use of high carbohydrate,
high protein or low fat diets have no scientific basis, and in some instances,
such diets may be harmful. Vitamin and mineral supplementation also has
no place in the management of chronic hepatitis unless some deficiency
is present. No substance is known that will help the main symptom, fatigue.
However, a good physical fitness program may lessen this distressing symptom.
Patients should be advised to limit the amount of salt that they use in
an attempt to forestall the accumulation of fluids as ascites or ankle
swelling. Since almost all drugs must be detoxified by the liver, and since
the injured liver does not perform this task well, limiting the amount
of drugs that a patient uses to only essential ones is important. This
includes discouraging the use of sedatives and tranquilizers.
Looking to the Future:
Learning more about the viruses
responsible for chronic hepatitis and how to control them will occur in
the next decade. Similarly, learning about the body's immune system and
how to control it has already begun. Preventive efforts will be enhanced
so that fewer cases of chronic hepatitis will develop. The goal of eliminating
this group of diseases seems to be just over the horizon, and while our
skills at transplantation are rapidly increasing, the form of therapy for
chronic hepatitis, like the disease itself, will disappear.
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Chronic Hepatitis