Viral Hepatitis Flashcards
1
Q
What are the main causes of hepatitis?
A
- Viral
- Non-viral; e.g. Toxoplasma gondii
- Drugs; e.g. paracetamol
- Alcohol
- Poisons; e.g. Aflatoxins, Amanita phalloides (mushrooms)
- Other; e.g. pregnancy, circulatory insufficiency
2
Q
What are the classifications of hepatitis?
A
Hepatitis A-E
Hepatitis F - ‘delisted’
Hepatitis G - ‘orphan’
3
Q
Describe hepatitis A-E
A
- All are hepatotropic - All demonstrate an ability to infect hepatocytes (liver cells)
- All belong to different virus families - All possess entirely different properties
4
Q
What are the 6 stages of viral replication?
A
- Adsorption
- Penetration
- Uncoating
- Replication of nucleic acid
- Maturation/assembly
- Release
5
Q
What is meant by the term hepatitis?
A
inflammation of the liver
6
Q
What are the viral features of HAV?
A
- Picornaviridae family
- Single-stranded RNA virus
- Non-enveloped virus (naked)
- Only 1 serotype
7
Q
How is HAV spread?
A
o Faecal-oral route
o Poor hand hygiene
o Contaminated food or water
8
Q
What are the main clinical features of HAV?
A
- Fever, anorexia
- Nausea, vomiting
- Jaundice
- Dark urine, pale stools
- Liver moderately enlarged
- Spleen palpable in 10% patients
- No chronic carriage
9
Q
How many viruses can be present in one gram of faeces?
A
100 million
10
Q
What are the stages of infection of HAV?
A
- Incubation period of 2-4 weeks (prodromal phase)
- Virus excreted in faeces for 1-2 weeks before symptoms
- Translocation from FI tract to blood
- Infection of liver cells
- Passage of biliary tract and back to GI tract
- Excretion in faeces
11
Q
What is the prognosis of HAV?
A
Prognosis excellent (mortality 0.1%) in young adults
12
Q
How could HAV cause death?
A
- Death if fulminant hepatic necrosis occurs
13
Q
How is HAV diagnosed?
A
- Diagnosed by presence of anti-HAV IgM
14
Q
What is the main treatment of HAV?
A
- No specific treatment
- Maintain comfort and nutritional balance
- Fluid and electrolyte replacement
15
Q
What is the main methods for prevention of HAV?
A
- Vaccine
- Good hygiene
- Resistant to chlorination
- Killed by boiling for 10mins
16
Q
What type of virus is HAV?
A
- Picornaviridae family
17
Q
Describe the viral features of HBV
A
- Hepadnaviridae
- Double-stranded DNA virus
- Enveloped virus
18
Q
What is the transmission method of HBV?
A
- Sexual intercourse
- Intra-uterine, peri- and post-natal infection
- Blood or blood products
- Contaminated needles and equipment used by intravenous drug users
- In association with tattooing, body piercing and acupuncture
- Contaminated haemodialysis
19
Q
Describe the antigens of hepatitis B
A
- HBsAg – surface antigen o Indicates high transmissibility o HBsAb provides immunity and appears late (not in carriers) - HBcAg – core antigen o HBcAb appears early in infection - HBeAg – envelope antigen o Derived from core o Indicates high infectivity
20
Q
Who is at risk HBV?
A
Anyone coming into contact with blood/body fluids from someone infected with HBV
e.g. sexual transmission, vertical transmission (mother - baby), living with a person with chronic HBV, drug users etc.)
21
Q
What are the stages of infection go HBV?
A
- Incubation period of 2-4 months
- 50% patients develop chronic active hepatitis
o 20% of these proceed cirrhosis - 1-4% of these risk developing liver cancer
22
Q
Describe the stages of acute infection of HBV
A
- Incubation period of 45-120 days
- Pre-icteric period of 1-7 days
- Icteric period 1-2 months
- Convalescent period of 2-3 months in 80-90% of adult cases
23
Q
How to distinguish between acute infection and chronic infection in Hep B?
A
- HBsAg and HBeAg appear during incubation period
- Viral DNA become detectable
- Antibodies to core antigen (HBcAg) appear concomitantly with rise in liver transaminases
- Antibodies to HBeAg and HBsAg only appear during convalescence
- Continued presence of HBsAg and absence of antibodies to it indicate that infection has become chronic
24
Q
Clinical features of the pre-iteric period of HBV
A
- Malaise
- Anorexia
- Nausea
- Pain in right upper quadrant (tender liver)
25
What are the clinical features of the steric period of HBV?
```
- Yellowish pigmentation
o Skin
o Sclerae
o Other mucous membranes
- Caused by hyperbilirubinemia
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26
What are the clinical outcomes of acute infection by HBV?
- Fulminant hepatitis
- Chronic hepatitis or asymptomatic carrier state
- Resolution of infection
27
What is the treatment for HBV?
- Pegylated interferon (peginterferon): superior compared to -interferon alone
- Nucleoside analogues such as oral lamivudine
28
What are the methods used for prevention go HBV?
- Vaccination: 3 injections over 6 months
- HBV immunoglobulin
- Blood screening
- Needle exchange programmes
- Sexual health education
29
Describe the viral features of HCV
- 6 virus types (from nucleotide sequences)
- Flaviviridae
- Single-stranded RNA
- Enveloped virus
30
What are the clinical features of HCV
- Usually asymptomatic
- Fatigue
- Nausea
- Weight loss
- May rarely progress to cirrhosis
- Small proportion to patients may develop hepatocellular carcinoma many years after primary infection
31
What are the modes of transmission of HCV?
- Blood borne products
- Blood contaminated needles
- Tattooing, body piercing, acupuncture
- Haemodialysis
32
What are the stages of infection of HCV?
- Virus replicates mainly in hepatocytes
| - Incubation period 2 weeks to 6 months
33
What are the screening procedures for HCV?
- Blood test available for HCV based on NAAT
| - Current incidence of transfusion associated HCV is low
34
What are the main treatments used for HCV?
- Ribavirin + pegylated -interferon
- Combination therapy
- No vaccine currently available
35
What are the viral features of HDV?
- Small (35nm) circular single-stranded RNA virus
- Defective virus
- HDV picks up HBsAg as it buds from liver cell
36
What is unique about Hep D?
- Found as co-infection with HBV
| - HBV severs as helper virus for infectious HDV production
37
How is HDV transmitted?
- Transmitted percutaneously, sexually, from infected blood
38
Who is mainly at risk for HDV?
- Chronic HBV carriers are at risk for infection with HDV
39
What is the main treatment for HDV?
- No specific treatment available
40
What are the viral features of HEV?
- Caliciviridae
- Single-stranded RNA
- Non-enveloped virus
41
What is the peak incidence of HEV?
- Peak incidence in young adults
42
What type of disease is HEV?
- Waterborne disease
| - Usually self-limiting
43
What is the incubation period of HEV?
- Incubation period 3-8 weeks
44
Who is HEV life threatening in?
pregnant woman
45
What are the main methods for prevention of HEV?
Good sanitation and hygiene
| Vaccine (Hecolin)
46
What are the main other causes of Viral Hepatitis?
- Epstein-Barr virus
- Cytomegalovirus
- Yellow fever virus
- Adenovirus
- Bunyaviruses
- Flaviviruses
