LMP301 Lecture 16: Viral Hepatitis Flashcards Preview

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Flashcards in LMP301 Lecture 16: Viral Hepatitis Deck (111)
1

Causes of hepatitis

1. drugs
2. toxins
3. bacteria
4. viruses
5. parasites

2

define: hepatitis

inflammation of the liver

3

drugs that may cause hepatitis

- anticonvulsants
- corticosteroids
- alcohol
- tylenol/asprin overdose

4

toxins that may cause hepatitis

- DDT
- mushrooms

5

bacteria that may cause hepatitis

- thyphoid fever

6

viruses that may cause hepatitis

- hepatitis A, B, C, D, E, G
- CMV
- EBV

7

parasites that may cause hepatitis

tapeworm

8

clinical symptoms of viral hepatitis

- enlarged liver
- elevated liver enzymes
- change colour of urine/feces
- accumulation of biliburin (jaundice)

9

on a virus particle, what can be used to identify the strain?

- ssDNA or RNA
- surface proteins (HBsAg)

10

define: antigen (Ag)

a substance (protein) that prompts the generation of antibodies -> immune response

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define: antibody (Ab/IgG/IgM)

proteins produced by B-cells which play an immunological role; identify & neutralizes foreign particles through antigens

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Which antibody is first released when there is an immune response? Which is released after?

IgM, then IgG

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IgM indicates...

primary immune response

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__ are produced during the primary immune response

memory lymphocytes

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The virus particle is surrounded by...

capsule coat

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The genetic material of virus is in the form of...

DNA or RNA (single or double stranded)

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what is directly inside the capsule coat?

Viral nucleocapsid (HBcAg)

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HBcAg

Viral nucleocapsid

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HBeAg

particles associated with nucleocapsid

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Where are HBeAg found?

inside the viral capsid (HBcAg)

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When does the production change from IgM to IgG?

after mature B cells are formed

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What is it called when IgG production begins and IgM production stops?

class-switching

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class-switching is....

a stable change in the B-cell's genome, and is transmitted to all progeny cells

24

Lifecycle of a virus

1. enters hepatocyte (capsule coat removed), viral DNA moves to nucleus of host
2. viral dsDNA -> cccDNA -> template for viral mRNA
3. viral mRNA transcription & assembly of new viral particles
4. viral proteins assemble around DNA core
5. new viral particles released from outer membrane of the host

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dsDNA -[?]-> cccDNA

cellular enzymes

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___ can persist in the hepatocyte during chronic infection

cccDNA

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cccDNA is genetic material of...

virus

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Steps of viral reproduction

1. Uncoating
2. Repair (formation of cccDNA)
3. Transcription
4. Translation

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How does release of viral particles determine host cell health?

If a little bit of the particle is released at a time, host lives
if all released, host dies

30

If the host cell dies, what happens to the viral production cycle?

it halts

31

Describe the Hep A virus

- small
- ssRNA (single protein core)
- no surface proteins to identify

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how is Hep A virus transmitted?

fecal-oral
- person-to-person contact
- contaminated water
- poor hygiene & sanitation

33

Who is at high risk for Hep A?

- children in daycare
- travelers to places where sanitation is bad

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onset of symptoms for Hep A

- very abrupt
- lasts 1 ~ 8 weeks

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what is a common clinical symptom of Hep A? How many adults develop this symptom?

jaundice
70-80%

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What is responsible for causing Hep A?

HAV

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where does HAV replicate?

in liver

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how does HAV leave the body?

through stool

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when is HAV most infectious (found in stool)?

first 2 weeks of contracting disease, a lot of HAV will be found in the stool

40

When does [HAV] decline in the stool?

after jaundice appears

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what happens to those people who have Hep A?

will recover, and develop immunity to HAV

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what is a marker used for diagnosing/confirming recent/acute HAV infection?

anti-HAV IgM + ALT (liver enzyme)

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what is a marker that indicates immunity to HAV?

anti-HAV IgG, and the absence of anti-HAV IgM in serum

44

clinical symptoms of Hep A appears about...

2 weeks after infection, and lasts until week 8 (duration: 6 weeks)

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What anti-HAV IgG a marker off?

past or present infection; cannot make a definitive diagnosis of a recent infection

46

genome of HBV

double stranded circular DNA

47

What are the 2 antigens found on HBV?

- Hep B surface antigen (HBsAg)
- Hep B core antigen (HBcAg)

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What is the structure that holds viral DNA?

central core nucleocapsid

49

What is the main structural difference between HAV and HBV?

HBV has a coat over the capsid that contains surface proteins

50

transmission of Hep B

exchange of body fluids
- needle
- transplant
- sex

51

individuals at risk for Hep B

- injection drug users
- unsafe sex
- occupation working with blood
- institutionalized populations (prisoners)

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incubation period for Hep B

60 - 90 days (2-3 months)

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Onset of Hep B is very...

subtle

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Less / More people develop jaundice when infected with HBV compared to HAV

less (only 30-50%)

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What happens to individuals infected with HBV?

recover within six months and develop immunity

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2-10% of infected individuals with Hep B will progress to...

chronic infection

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15-50% of people with chronic Hep B...

die prematurely as a result of chronic liver disease

58

Markers of Hep B

- HBsAg
- HBeAg
- anti-HBc (IgM)
- anti-HBe (IgG)
- anti-HBs (IgG)

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HBsAg

Hep B surface antigen

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HBeAg

Hep B envelope antigen

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What can be used to identify the strain of Hep B?

type of HBsAg and HBeAg that can be found in serum

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Anti-HBc (IgM)

IgM antibody to the core antigen

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Anti-Hbe (IgG)

antibody to HBe antigen

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Anti-Hbs (IgG)

antibody to HBs antigen

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What can be used to identify the stage of hepatitis infection?

see which antibody is secreted by the body (IgM or IgG)

66

What is used to follow patient progress throughout hepatitis infection?

serial testing: follow patient's progress using markers (HBsAg, HBeAg, anti-HBe, anti-HBs)

67

What markers can be seen for acute hepatitis?

- HBsAg = there are surface antigens
- HBeAg = there are envelop antigens
- anti-HBc (IgM) = there is a core

(the viral parts, mostly)

68

duration of an acute Hep B infection

2 weeks - 3 months

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what markers appear during early recovery and recovery phase of Hep B?

anti-HBs & anti-HBe

(the antigens)

70

duration of early recovery period for Hep B

3-6 months

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duration of recovery for Hep B

6-12 months / years

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what is the last marker to appear for Hep B?

anti-HBs

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What does the presence of anti-HBs and anti-HBe indicate?

- Hep B is resolving (leaves acute stage)
- establishment of immunity

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individual is considered chronically infected if...

HBsAg is present for more than six months

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what markers can be seen for chronic hep B infection?

- HBsAg and HBeAg are elevated even at later stage
- antibodies to those viral particles are also constantly present

76

Hep B: indicator of disease resolution

Anti-HBe

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Hep B: indicator of recovery & immunity

Anti-HBs

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Hep B: indicator of acute infection (unique to this category)

Anti-HBc (IgM)

79

genomic material of HCV

ssRNA encased by nucleocapsid (core)

80

difference between envelope of HBV and HCV

HCV has an envelope proteins, but they can't be used to identify the strain

81

HCV is encased by...

lipid envelope

82

size of HCV

< 50 nm
very small

83

transmission of HCV

blood
- needle
- transfusion
- perinatal

84

individuals at risk for Hep C

- injection drug users
- occupational hazard
- transfusions before 1992
- institutionalized populations (prisoners)

85

60-70% of people with Hep C have what symptom?

asymptomatic!

86

20-30% of people with acute Hep C have what symptom?

jaundice

87

___% of Hep C patients become chronically infected

60-85

88

10-20% of people with chronic Hep C develop _____

cirrhosis

89

1-5% of people with chronic Hep C develop _____

hepatocellular carcinoma

90

hepatocellular carcinoma occurs over...

20-30 years (latent infection)

91

HCV is a leading cause of....

liver transplants

92

HCV reacts differently depending on...

what other "factors" you have
- alcohol use
- HIV
- drugs
...

93

duration of incubation for HCV

2-26 weeks
avg: 6-7 weeks

94

when do people infected with HCV develop symptoms?

6-7 weeks

95

define: seroconversion

development of antibodies in response to disease states

96

how long does it take before seroconversion occurs for Hep C?

8-9 weeks

97

What individuals are considered infectious for Hep C?

* positive for HCV antibody

liver enzymes could still be normal

98

why might there not be an elevation in liver enzymes for those with Hep C?

slow infection cycle allows liver to slowly adjust to the increasing strain

99

how is HCV diagnosed?

1. detecting antibodies specific to HCV (anti-HCV)
2. ruling out HAV or HBV

100

symptoms of Hep C appears during...

week 1 - week 5 of infection period

101

downside of using anti-HCV as marker for diagnosis

- may not appear if tested early
- can take >2 months to become positive
- does not distinguish between acute & chronic
- can't tell when they got the disease

102

what can be found at a constant level for those infected with HCV?

HCV RNA

103

what liver enzyme is abnormal in Hep C individuals, and what is the serologic pattern like?

- ALT
- more abundant than normal (peak about week 2-3)
- decreases and goes fluctuates, slightly above normal range later on

104

serologic pattern for anti-HCV

increase as duration of Hep C increases (exponential)

105

HCV RNA measure...

level of circulating virus = "viral load"

106

high viral load means that...

the virus is replicating a lot

107

Why is HCV RNA testing used?

- detect HCV before anti-HCV may be formed
- access viral load before and after treatment
- detect HCV infection in cases with ambiguous serology (blood test)

108

which viral hepatitis has abrupt onset

Hep A

109

which hep virus has the shortest incubation time?

hep A

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which hep virus will most likely cause a chronic infection?

hep C

111

which hep virus has the highest mortality rate?

HCV