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MD3002 Week 5 > 1. Viral Hepatitis > Flashcards

1. Viral Hepatitis Flashcards

1
Q

Causes of hepatitis?

A 
Viral (Hep A-E)
Non-viral
Drugs e.g. paracetamol
Alcohol
Poisons e.g. Aflatoxins
Other e.g. pregnancy, circulatory insufficiency
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2
Q

What do hepatitis viruses A-E all have in common?

A

All are hepatotropic i.e. are able to infect hepatocytes (liver cells). However are all part of different virus families

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3
Q

6 stages of viral replication?

A 
Adsorption
Penetration
Uncoating
Replication of nucleic acid
Maturation/ assembly
Release
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4
Q 
Hep A Virus:
Viral features?
Transmission?
Shellfish as a source of infection?
Stages of infection?
A

Viral features:
• Picornaviridae family
• Single-stranded RNA virus
• Non-enveloped virus (naked) • Only 1 serotype

Transmission:
– Faecal-oral route
– Poor hand hygiene
– Contaminated food or water

Shellfish as a source of infection:
If water is contaminated with sewage when shellfish filter water, the virus concentrations in flesh. Eating raw or partly cooked shellfish leads to infection

Stages of infection:
• Incubation period of 2-4 weeks leads into prodromal phase (a.k.a pre-icteric stage)
• Virus excreted in faeces for 1-2 weeks before symptoms
• Translocation from GI tract to blood
• Infection of liver cells
• Passage to biliary tract and back to GI tract
• Excretion in faeces

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5
Q

HAV:
Clinical features?
Treatment?
Prevention?

A 
Clinical features:
• Fever, anorexia
• Nausea, vomiting
• Jaundice
• Dark urine, pale stools
• No chronic carriage
• Presence of anti-HAV IgM

Treatment?
• No specific treatment
• Maintain comfort and nutritional balance
• Fluid and electrolyte replacement

Prevention:
• Vaccine
• Good hygiene
• Resistant to chlorination
• Killed by boiling for 10 mins
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6
Q

Hep B Virus:
Viral features?
Antigens?

A

Viral features:
• Hepadnaviridae
• Double-stranded DNA virus
• Enveloped virus

Antigens:

  • HBsAg= Surface antigen. Indicates high transmissibility and provide immunity
  • HBcAg= Core antigen
  • HBeAg= Envelope antigen. Indicates high infectivity
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7
Q

HBV:

Transmission?

A

Transmission:
• 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 equipment

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8
Q

HBV: Stages of infection?

A

• Incubation period of 2-4 months
• 50% patients develop chronic active hepatitis
–> 20% of these proceed to cirrhosis
–> 1-4% of these risk developing liver cancer

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9
Q

HBV, difference between an acute and chronic infection?

A
  • HBsAg and HBeAg appear during incubation period
  • Viral DNA becomes 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

Chronic: No antibody for surface antigen. Surface antigen levels don’t drop down. Leads to infection

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10
Q

Stages of an acute HBV?

A
  • Incubation period of 45 – 120 days
  • Pre-icteric period of 1 – 7 days
  • Icteric period of 1 – 2 months
  • Convalescent period of 2 – 3 months in 80-90% of adult cases
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11
Q

Clinical features of icteric period of HBV? Cause?

A

Yellowish pigmentation: Skin, sclerae, other mucous membranes

Caused by hyperbilirubaemia

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12
Q

What does fulminant mean?

A

Severe and sudden in onset

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13
Q

Clinical outcomes of acute HBV infection?

A

• Fulminant hepatitis
• Chronic hepatitis or asymptomatic carrier
state
• Resolution of infection

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14
Q

HBV treatment and prevention?

A

Treatment:
• Pegylated interferon (peginterferon): superior
compared to α-interferon alone
• Nucleoside analogues such as oral lamivudine

Prevention:
• Vaccination: 3 injections over 6 months. Against the surface antigen
• HBV immunoglobulin
• Blood screening
• Needle exchange programmes
• Sexual health education
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15
Q

Hep C Virus:
Viral features?
Clinical features?

A 
Viral features:
• 6 virus types (from nucleotide sequences)
• Flaviviridae
• Single-stranded RNA
• Enveloped virus
Clinical features:
• Usually asymptomatic
• Fatigue
• Nausea
• Weight loss
• May rarely progresses to cirrhosis
• Small proportion of patients may develop hepatocellular carcinoma many years after primary infection
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16
Q

HCV:
Transmission?
Stages of infection?

A 
Transmission:
• Blood and blood products
• Blood contaminated needles
• Tattooing, body piercing, acupuncture
• Haemodialysis

Stages of infection:
• Virus replicates mainly in hepatocytes
• Incubation period 2 weeks to 6 months

17
Q

HCV: Prevention and treatment?

A

Prevention:

  • Screening: Blood test based on NAAT
  • No vaccine

Treatment:

  • Ribavirin + pegylated alpha-interferon.
  • Combination therapy(HAART) : Sofosbuvir, boceprevir, telaprivir, daclatasvir
18
Q

HBV: Clinical Features of Pre-icteric Period?

A
  • Malaise
  • Anorexia
  • Nausea
  • Pain in right upper quadrant (tender liver)
19
Q

Hep D Virus:

Viral features?

A

Viral features:
• Small (35nm) circular single-stranded RNA virus
• Defective virus
• HDV picks up HBsAg as it buds from liver cell (i.e. only comes in co infection with HBV)

20
Q 
HDV:
What is function of HBV?
Transmission?
What increases risk for HDV infection?
Treatment?
A

What is relevance of HBV:
• Found as co-infection with HBV
• HBV serves as helper virus for infectious HDV production

Transmission: Percutaneously, sexually, from infected blood

What increases risk for HDV infection: Chronic HBV carriers are at risk for infection with HDV

Treatment: None

21
Q 
Hep E Virus:
Viral features?
Incidence?
Transmission and symptoms?
Prevention?
A

Viral features:
• Caliciviridae
• Single-stranded RNA
• Non-enveloped virus

Incidence: Young adults. Can be life-threatening in pregnant woman

Transmission and symptoms:
• Waterborne disease
• Incubation period 3-8 weeks
• Usually self-limiting
• Signs and symptoms are similar to other acute forms of hepatitis

Prevention:
• Good sanitation & hygiene
• Vaccine (Hecolin)

22
Q

6 other causes for viral hepatitis?

A
  • Epstein-Barr virus
  • Cytomegalovirus
  • Yellow fever virus
  • Adenoviruses
  • Bunyaviruses
  • Flaviviruses

MD3002 Week 5 (8 decks)

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