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Flashcards in Infection Deck (188)
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90

How is group M of HIV 1 subclassified!!?
What is the clinical relevance?

A-K - CRF (circulating recombinant forms on co-infection)
West mainly B
Same tx but different response

91

What is the histological structure of the hiv virus?

Enveloped
SsRNA with reverse transcriptase

92

What is the lifecycle of HiV

Gp120 binds to CD4
Virus fuses with plasma expelling contents
Reverse transcriptase converts rna to dna
Dna intergrates into host genome
Production of viral mrna and proteins
Caspid assemble and buds from cell

93

At what point is a hiv infection irreversible?

Once the dna intergrates into the host genome

94

How long is the incubation period for HiV
What happens at the end of it?

2-6 weeks
Seroconversion

95

How does hiv seroconversion present?

Only 25% ill enough to attend hcp
Non specific illness, fever, rash, sore throat, lymphadonopathy, headache

96

How many hiv infected people get seroconversion? What does it mean prognostically?

50-75%
May be at risk of more accelerated disease course.

97

What is the term for the period between seroconversion and symptomatic hiv? What may be present?

Latent period
Lymphadenopathy

98

What may be detectable in a hiv pt undergoing a seroconversion reaction?

Lymphopdnia
Low cd4;cd8 ratio
Circulating viral rna
Viral p24 antigen

99

What causes symptomatic hiv?
How does it present?

Neurotoxins from hiv, cytokine abnormalities, low immunity

Aseptic meningitis, dementia, polyneuropathy, puritis, anaemia, anorexia, diarrhoea, weight loss ,

100

What are aids defining illnesses?

Candida of lower airways/oesophagus
Karposi's sarcoma
Tb
Pneumocystis jiroveci
Cmv retinitis
Hiv encephalitis

101

What is the hiv core antigen?

P24

102

What blood test will first show hiv?
When?

Viral p24 antigen
2 to 8 weeks

103

What IgG tests can be used to detect hiv?

IgG to envelope - takes 3 months to build
IgG to core (p24) - detectible after weeks but lost as disease progresses

104

How are hiv antigens detected and assessed?

Elisa followed by western blotting

105

How would you not hiv test a baby of a infected mother?

Using IgG - it crosses the placenta so all babies will be positive

106

What are the general classes of antiretrovirals?
What is the term for the combination used in. hiv?

Reverse transcriptase inhibitors
Protease inhibitors
Fusion inhibitors

107

What are the subtype of reverse transcriptase inhibitors?

Nucleoside (NRTISs)
Nucleotide (NtRTIs)
Non-nucleoside (NNRTIs)

Highly active antiretroviral therapy (haart)

108

What is a big side effect associated with NRTIs?

Effect mitochondria so lactic acidosis

109

What is the lifecycle of HBV?

Attaches to and enters hepatocyte
Looses coat and core enters nucleus
Processing of dna with reverse transcriptase
New virons enter blood

110

How is hepatic damage caused in hbv?

Immune response against virus

111

What are the immediate outcomes post infection with HBv? What percentage of patients do which?

Acute infections - clear (89%)
Acute infection - death (1%)
Acute infection - chronic infections (10%

112

What are the symptoms of acute hbv infection?

Malaise
Jaundice
Nausea/vomiting
Weight loss
Diarrheoa

113

What causes death in acute hbv infection?

Fulminant hepatic failure

114

What age group is more likely to develop a chronic hbv infection?

Children (esp infants)

115

How can chronic hbv present?

Progressive - cirrhosis - risk of liver carcinoma
Non-progressive

116

How do hbv antibodies change over the course of a disease with recovery?

Initial rise in HBs antigen and HBc IgG
HBs antigen falls
HBs IgG rises

117

How do hbv antibodies change in a chronic disease?

Rise and maintainance of HBc IgG and HBc antigen

118

If someone is vaccinated against hbv what antibody would you expect to be high? What would indicate that they had been infected?

HBs IgG

If infected HBc antigen and IgG

119

How can HBV be prevented?

Lifestyle changes/PPE
HBs antigen vaccination
PEP with immunoglobulin