EXAM #2: HIV I Flashcards

1
Q

List four reasons that HIV is very challenging to treat and manage?

A

1) High genetic mutation rate
2) Evades cellular and humoral immunity
3) Evades traditional vaccine strategies
4) “Hides” in resting memory CD4+ T-cells

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2
Q

What is the definition of AIDS?

A

1) CD4+ T-cell count less than 200 OR

2) AIDS defining illness

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3
Q

What is the importance of the “viral load set point?”

A

High viral load set-point= progress to AIDS quickly

Low viral load set-point= slow progression to AIDS

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4
Q

What virus causes Kaposi Sarcoma?

A

HHV-8

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5
Q

At what CD4+ T-cell count to HIV+ patients get Kaposi Sarcoma?

A

400

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6
Q

At what CD4+ T-cell count to HIV+ patients get toxoplasmosis and cryptococcosis?

A

100

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7
Q

At what CD4+ T-cell count to HIV+ patients get MAC?

A

50

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8
Q

What is the difference between a single pneumococcal pneumonia diagnosis vs. recurrent pyogenic bacterial pneumonia?

A
Recurrent= AIDS defining
Single= NOT defining, but should include HIV as part of differential
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9
Q

What is the current trend of HIV infections in the US?

A
  • No real change in incidence year-to-year

- More people are living longer with HIV

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10
Q

What group has the highest risk of new HIV diagnosis?

A

Male-to-male (MSM)

*Note that in this group the incidence of HIV infection is INCREASING

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11
Q

What is the trend of HIV diagnoses in African Americans?

A

Account for roughly 1/2 of all diagnoses

*Minorities are “disproportionately affected”

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12
Q

What percent of the population is HIV+ but doesn’t know it?

A

Roughly 20%

*Note that they account for roughly half of the new HIV infections

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13
Q

What % of CD4+ T-cells is associated with AIDS?

A

AIDS= CD4+ T-cell % less than 14

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14
Q

What is acute retroviral syndrome?

A

Initial viral illness after infection with HIV

*Commonly a prolonged flu/mono like illness

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15
Q

What symptoms can be associated with acute retroviral syndrome aside from flu/mono sx?

A
  • Pharyngitis, rash* or headache
  • Aseptic meningitis
  • Oral/ genital ulcers

*This can differentiate from EBV

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16
Q

In terms of HIV diagnosis, what is the first test that will be positive?

A

Viral RNA (week - two weeks post exposure)

17
Q

What protein makes up the HIV viral capsid?

A

p24

18
Q

How is HIV diagnosed?

A

1) HIV RNA PCR

2) HIV antigen (p24)/antibody testing

19
Q

What is the gold standard for HIV screening?

A

ELISA

20
Q

How is the diagnosis of HIV confirmed?

A

1) HIV-1 Western Blot

2) Multispot HIV-1/HIV-2 test

21
Q

A reactive HIV antigen/antibody screening test is positive; multispot test for HIV-1/2 is negative. What should you do?

A

HIV RNA PCR

22
Q

What are the current screening recommendations for HIV screening?

A

15 - 65 y/o as an “opt out” test i.e. you can elect not to do the test

23
Q

When is repeat screening for HIV recommended?

A

High risk individuals (MSM)–should be tested once a year

24
Q

What are the HIV screening recommendations for pregnant women?

A

Test all women*

*Law in IA

25
Q

How does HIV-2 differ from HIV-1?

A

1) Less transmissable
2) Less pathogenic
3) Less likely to cause AIDS

*Coinfection is possible

26
Q

What receptors/ co-receptors mediate HIV viral entry?

A

Receptor= CD4

Co-receptor=

  • CCR5
  • CXCR4
27
Q

What co-receptor does the HIV that is sexually transmitted have a trophism for?

A

CCR5

28
Q

What is a CXCR4 trophism associated with?

A

Faster progression to AIDS

29
Q

What is the protein on the AIDS virus that binds to CCR5?

A

gp120

30
Q

What are the benefits of a delta 32 CCR5 mutation? What is the difference between homozygous and heterozygous mutations?

A

Interferes with the co-receptor for HIV

  • Heterozygous= slow progression to AIDS
  • Homozygous= v. challenging to get infected with HIV