VIRAL HEPATITIS
INTRODUCTION
Hepatitis refers to an inflammatory
condition of the liver. It’s commonly caused by a viral infection, but there
are other possible causes of hepatitis. These include autoimmune hepatitis and
hepatitis that occurs as a secondary result of medications, drugs, toxins, and
alcohol. Autoimmune
hepatitis is a disease that occurs when
your body makes antibodies against your liver tissue.
Viral hepatitis is caused
mainly by infection with one of the five hepatitis viruses, which use the liver
as their primary site of replication. Each of these, known as hepatitis A
through E viruses (HAV to HEV), belong to different virus families, have unique
morphology, genomic organization and replication strategy. These viruses cause
similar clinical manifestations during the acute phase of infection but vary in
their ability to cause chronic infection. While HAV and HEV cause only acute
disease with no chronic sequelae, HBV, HCV and HDV cause varying degrees of
chronicity and liver injury, which can progress to cirrhosis and liver cancers.
Though specific serological tests are available for the known hepatitis
viruses, nearly 20% of all hepatitis cases show no markers. Antiviral therapy
is also recommended for some hepatitis viruses and a preventive vaccine is
available only for hepatitis B. More research and public awareness programmes
are needed to control the disease.
TYPES
OF HEPATITIS
·
Infectious
·
Non infectious
INFECTIOUS HEPATITIS
Viral infections of the liver that are
classified as hepatitis include hepatitis A, B, C, D, and E. A different virus
is responsible for each type of virally transmitted hepatitis. Hepatitis A is
always an acute, short-term disease, while hepatitis B, C, and D are most
likely to become ongoing and chronic. Hepatitis E is usually acute but can be
particularly dangerous in pregnant women.
Hepatitis
A
Hepatitis A is caused by
an infection with the hepatitis A virus (HAV). This type of hepatitis is most
commonly transmitted by consuming food or water contaminated by feces from a
person infected with hepatitisA.
Hepatitis
B
Hepatitis B is transmitted
through contact with infectious body fluids, such as blood, vaginal secretions,
or semen, containing the hepatitis B virus (HBV). Injection drug use, having
sex with an infected partner, or sharing razors with an infected person increase
your risk of getting hepatitis B.
Hepatitis C
Hepatitis C comes
from the hepatitis C virus (HCV). Hepatitis C is transmitted through direct
contact with infected body fluids, typically through injection drug use and
sexual contact. HCV is among the most common bloodborne viral infections.
Hepatitis
D
Also called delta hepatitis, hepatitis D is a
serious liver disease caused by the hepatitis D virus (HDV). HDV is contracted
through direct contact with infected blood. Hepatitis D is a rare form of
hepatitis that only occurs in conjunction with hepatitis B infection. The
hepatitis D virus can’t multiply without the presence of hepatitis B. It’s very
uncommon in the United States.
Hepatitis
E
Hepatitis E is a
waterborne disease caused by the hepatitis E virus (HEV). Hepatitis E is mainly
found in areas with poor sanitation and typically results from ingesting fecal
matter that contaminates the water supply. This disease is uncommon in the
United States. However, cases of hepatitis E have been reported in the Middle
East, Asia, Central America, and Africa, according to the CDC
Non-infectious hepatitis
CAUSES
Alcohol and other toxins
Excessive
alcohol consumption can cause liver damage and inflammation. This is sometimes
referred to as alcoholic hepatitis. The alcohol directly injures the cells
of your liver. Over time, it can cause permanent damage and lead to liver
failure and cirrhosis, a thickening and scarring of the liver.
Other toxic
causes of hepatitis include overuse or overdose of medications and exposure to
poisons.
Autoimmune system response
In some
cases, the immune system mistakes the liver as a harmful object and begins to
attack it. It causes ongoing inflammation that can range from mild to severe,
often hindering liver function. It’s three times more common in women
than in men.
SIGNS
AND SYMPTOMS
If infectious forms of hepatitis that
are chronic, like hepatitis B and C, there may not be symptoms in the
beginning. Symptoms may not occur until the damage affects liver function.
Signs and symptoms of acute hepatitis appear quickly. They include:
·
abdominal pain
·
unexplained weight
loss
Chronic hepatitis develops slowly, so these signs and symptoms may be
too subtle to notice.
MANAGEMENT (INVESTIGATIONS
AND TREATMENT)
DIAGNOSIS
History and physical examination
To diagnose
hepatitis, history to determine any risk factors for infectious or
noninfectious hepatitis.
During a
physical examination, press down gently on the abdomen to see if there’s pain
or tenderness or liver is enlarged. If skin or eyes are yellow, it is noted
during the examination.
Liver function tests
Liver
function tests use blood samples to determine how efficiently the liver works.
Abnormal results of these tests may be the first indication that there is a
problem, especially if there are no signs on a physical examination of liver
disease. High liver enzyme levels may indicate that the liver is stressed,
damaged, or not functioning properly.
Other blood tests
If the liver
function tests are abnormal, bloodtests may be done to detect the source of the
problem. These tests can check for the viruses that cause hepatitis. They can
also be used to check for antibodies that are common in conditions like
autoimmune hepatitis.
Ultrasound
An abdominal
ultrasound uses ultrasound waves to create an image of the organs
within your abdomen. This test allows to take a close look at the liver and nearby organs. It can
reveal:
·
fluid in
the abdomen
·
liver
damage or enlargement
·
liver tumors
·
abnormalities
of your gallbladder
Sometimes
the pancreas shows up on ultrasound images as well. This can be a useful test in
determining the cause of the abnormal liver function.
Liver biopsy
A liver
biopsy is an invasive procedure that involves taking a sample of
tissue from the liver. It can be done through the skin with a needle and
doesn’t require surgery. Typically, an ultrasound is used to guide the
physician when taking the biopsy sample.
This test allows
determining how infection or inflammation has affected the liver. It can also
be used to sample any areas in the liver that appears abnormal.
TREATMENT
Treatment
options are determined by which type of hepatitis you have and whether the
infection is acute or chronic.
Hepatitis A
Hepatitis A
usually doesn’t require treatment because it’s a short-term illness. Bed rest
may be recommended if symptoms cause a great deal of discomfort. The hepatitis
A vaccine is available to prevent this infection. Most children begin
vaccination between ages 12 and 18 months. It’s a series of two vaccines.
Vaccination for hepatitis A is also available for adults and can be combined
with the hepatitis B vaccine.
Hepatitis B
Acute
hepatitis B doesn’t require specific treatment. Chronic hepatitis B is treated
with antiviral medications. This form of treatment can be costly because it
must be continued for several months or years. Treatment for chronic hepatitis
B also requires regular medical evaluations and monitoring to determine if the
virus is responding to treatment. Hepatitis B can be prevented with
vaccination. The CDC recommends hepatitis B vaccinations for all
newborns. The series of three vaccines is typically completed over the first
six months of childhood. The vaccine is also recommended for all healthcare and
medical personnel.
Hepatitis C
Antiviral
medications are used to treat both acute and chronic forms of hepatitis C.
People who develop chronic hepatitis C are typically treated with a combination
of antiviral drug therapies. They may also need further testing to determine
the best form of treatment.
People who
develop cirrhosis (scarring of the liver) or liver disease as a result of
chronic hepatitis C may be candidates for a liver transplant.
Currently,
there is no vaccination for hepatitis C.
Hepatitis D
No antiviral
medications exist for the treatment of hepatitis D at this time. According to a
study, a drug called alpha interferon can be used to treat hepatitis D.
Hepatitis D can be prevented by getting the vaccination for hepatitis B, as
infection with hepatitis B is necessary for hepatitis D to develop.
Hepatitis E
Currently,
no specific medical therapies are available to treat hepatitis E. Because the
infection is often acute, it typically resolves on its own. People with this
type of infection are often advised to get adequate rest, drink plenty of
fluids, get enough nutrients, and avoid alcohol. However, pregnant women who
develop this infection require close monitoring and care.
Autoimmune hepatitis
Corticosteroids,
like prednisone or budesonide, are extremely important in the early treatment
of autoimmune hepatitis. Azothioprine (Imuran), a drug that suppresses the
immune system, is often included in treatment. It can be used with or without
steroids. Other immune suppressing drugs like mycophenolate (CellCept),
tacrolimus (Prograf) and cyclosporine (Neoral) can also be used as alternatives
to azathioprine for treatment.
PREVENTION
1.
Hygiene
Practicing
good hygiene is one key way to avoid contracting hepatitis A and E. If you’re
traveling to a developing country, you should avoid:
·
local
water
·
ice
·
raw or
undercooked shellfish and oysters
·
raw fruit
and vegetables
Hepatitis B,
C, and D contracted through contaminated blood can be prevented by:
·
not
sharing drug needles
·
not
sharing razors
·
not using
someone else’s toothbrush
·
not
touching spilled blood
Hepatitis B
and C can also be contracted through sexual intercourse and intimate sexual
contact. Practicing safe sex by using condoms can help decrease the
risk of infection.
2.
Vaccines
The use of
vaccines is an important key to preventing
hepatitis. Vaccinations are available to prevent the development of
hepatitis A and B. Experts are currently developing vaccines against hepatitis
C. A vaccination for hepatitis E exists in China.
PATHOPHYSIOLOGY: Each of the hepatitis
viruses cause similar liver damage. The inflammatory process is activated
throughout the whole liver, and hepatocytes are destroyed by cytotoxic
cytokines and natural killer cells, both parts of the inflammatory
process. Cellular necrosis takes place.
If inflammation affects the periportal areas, cholestasis, or the interruption
of the flow of bile takes place. The liver is usually able to repair itself and
regain complete function if no other complications occur.
The antigen-antibody
complexes that are formed from the interaction of the immune system with the
infection circulate thoughout the body, which activates the complement system.
The person feels malaise, rash, arthritis, fever and angioedema from this
activation. Abnormal protiens are also produced in the blood, termed
cryogloblinemia. The person may also develop vasculitis and glomerulonephritis.
There are three phases
during a typical course of acute hepatitis.
1. Prodromal phase.
This phase begins about 2 weeks after exposure to hepatitis. The infection is
easily transmitted during this phase. The signs and symptoms are malaise,
fatigue, anorexia, nausea, vomiting, cough, hyperalgia, low-grade fever. This
stage ends when jaundice appears.
2. Icteric phase. This
phase is characterized by dark urine, jaundice and clay-colored stools. The
liver becomes enlarged, tender and smooth and the person feels pain if the
liver is percussed. This is known as the actual phase of illness. It begins 1-2
weeks after the prodromal phase and continues for 2-6 weeks.
3. Recovery phase. The
recovery begins when the jaundice starts to clear. The liver stays enlarged and
tender but the other symptoms start to diminsh. It usually begins 6-8 weeks
after exposure. The liver regains normal function 2-12 weeks after the jaundice
begins.
Chronic hepatitis is
defined as "the persistance of clinical manifestations and liver
inflammation after acute hepatitis B, hepatitis C, and hepatitis D. Liver
function tests remain abnormal for longer than 6 months, and hepatitis B
surface antigen (HbsAg) persists" .
Complications of hepatitis
Chronic hepatitis B or C can often lead to more serious health problems.
Because the virus affects the liver, people with chronic hepatitis B or C are
at risk for:
·
chronic liver
disease
·
cirrhosis
When the liver stops functioning normally, liver failure can occur.
Complications of liver failure include:
·
bleeding disorders
·
hepatic
encephalopathy, which can involve
fatigue, memory loss, and diminished mental abilities due to the buildup of
toxins, like ammonia, that affect brain function
·
hepatocellular
carcinoma, which is a form of liver cancer
·
death
People with chronic
hepatitis B and C are encouraged to avoid alcohol because it can accelerate
liver disease and failure.
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