Hepatitis
Contents
• Hepatitis
• Symptoms
• Structure of HBV
• Stages
• Types
Objectives
At the
end of this lecture, students will be able to –
• Identify the symptoms of hepatitis
• Describe the structure of HBV
• Explain different stages of hepatitis
Hepatitis
• Inflammation
of liver
• Results
in damage to hepatocytes with subsequent cell death
Etiology of hepatitis
• Viral
infections – Hepatitis A, B, C, D, E ; Epstein barr virus, yellow fever virus,
cytomegalo virus & herpes virus
• Autoimmune
chronic hepatitis
• Toxins
, Alcohol
• Drugs
used for the treatment of tuberculosis e.g. Isoniazid
Symptoms of hepatitis
|
Initial symptoms |
Final symptoms |
|
Hepatic symptoms are flu like |
Jaundice |
|
Mild fever, Chills |
Dark urine |
|
Headache |
Pale faeces containing puss cells |
|
Nausea, Vomiting, Diarrhoea |
Pruritis |
|
Anorexia, Fatigue |
Enlargement of spleen |
|
Slight abdominal pain |
Urticaria |
|
Aching of joints |
Dizziness, Drausiness, circulation problem |
Types of hepatic viruses
|
Name of virus |
Content |
Mode of spread |
|
Hepatitis A virus (HAV) |
RNA |
Faeces |
|
Hepatitis B virus (HBV) |
DNA |
Parenteral, Sexual contact, Blood transfusion, Babies born
to HBV infected mothers |
|
Hepatitis C virus (HCV) |
RNA |
Parenteral transmission, IV drug abuse, needle sharing |
|
Hepatitis D virus (HDV) |
RNA |
Super infection |
|
Hepatitis E virus (HEV) |
RNA |
Transmitted enterically |
|
Hepatits G virus (HGV) |
RNA |
Parenterally transmitted hepatotropic virus |
Structure of HBV
• Only
DNA containing virus
• Belongs
to group ‘hepadnaviridae’
• Diameter-
42 nm; incubation period is 6-8 weeks
• Comprises
of core and a capsule
• Core
consists of DNA & DNA polymerase
• Core
is surrounded by markers
– Hepatitis
B core antigen (HBc
Ag)
– Hepatitis
B envelope antigen (HBe
Ag)
– Hepatitis
B surface antigen (HBs Ag)
Mode
of transmission of
• Present
in all body secretion
• A
close contact with an infected person spreads the disease
• By
blood transfusion
• Not
through fecal matter
Stages of hepatitis (Assessed by different markers)
Stage 1
• HBs Ag is identified in
asymptomatic phase
• It
appears even before the onset of a disease
• Reaches
the peak level during disease stage
• The
counts become less with in 3-6 months
Stage 2
• HBe Ag, HBV DNA, DNA
polymerase appears
• HBe Ag – indicates the
progression of infection
• Continues
viral replication
Stage 3
• IgM
and anti HBc is detected
• Ab
is identified just before the onset of symptoms
• After
several months of infections IgG and anti HBc
Phases of HBV infection
Proliferative phase
• Shows
the presence of symptoms
• DNA
of HBV has accessory replicative chromosomes and forms virions
• HBs
antigen binds with MHC class molecule and activated CD8+ T-cells
Integrative phase
• Viral
DNA gets incorporated into the host genome
• Damage
of hepatocytes by activation of CD8+ T-
cells
Types
of Hepatitis
Acute hepatitis – comprises of 4 phases
1. Incubation period
–depends on type of virus
• HAV
– 12 weeks
• HBV
– 10 weeks
• HCV
– 7 weeks
• HDV
– 6 weeks
• HEV
– 2-8 weeks
Patient does not show any signs or symptoms in incubation
period
2. Symptomatic pre –
icteric phase
• Non
specific symptoms like fatigue, nausea, vomiting, weight loss, low fever,
headache, muscle & joint aches, diarrhoea
3. Symptomatic
icteric phase
• Yellow
coloration appears
• Jaundice
appears in 3rd stage
4. Phase of recovery
• Takes
place depending upon the severity of infection
Chronic hepatitis
• Hepatic
diseases remain for more than 6 months
• Inflammation
& necrosis takes place
• Fatigue,
Malaise, Lack of apetite, mild jaundice
• Symptoms
are highly variable & not predictive in nature
Summary
• Hepatitis
is inflammation of liver that results in damage to hepatocytes with subsequent
cell death
• It
may occur due to viral , autoimmune chronic hepatitis, Toxins, Alcohol and
drugs
• HBV
is main causative organism
• Types of hepatitis include acute and chronic
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