EXAM #2: HIV I Flashcards Preview

Infectious Disease > EXAM #2: HIV I > Flashcards

Flashcards in EXAM #2: HIV I Deck (30):
1

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

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

2

What is the definition of AIDS?

1) CD4+ T-cell count less than 200 OR
2) AIDS defining illness

3

What is the importance of the "viral load set point?"

High viral load set-point= progress to AIDS quickly
Low viral load set-point= slow progression to AIDS

4

What virus causes Kaposi Sarcoma?

HHV-8

5

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

400

6

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

100

7

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

50

8

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

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

9

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

- No real change in incidence year-to-year
- More people are living longer with HIV

10

What group has the highest risk of new HIV diagnosis?

Male-to-male (MSM)

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

11

What is the trend of HIV diagnoses in African Americans?

Account for roughly 1/2 of all diagnoses

*Minorities are "disproportionately affected"

12

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

Roughly 20%

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

13

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

AIDS= CD4+ T-cell % less than 14

14

What is acute retroviral syndrome?

Initial viral illness after infection with HIV

*Commonly a prolonged flu/mono like illness

15

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

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

*This can differentiate from EBV

16

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

Viral RNA (week - two weeks post exposure)

17

What protein makes up the HIV viral capsid?

p24

18

How is HIV diagnosed?

1) HIV RNA PCR
2) HIV antigen (p24)/antibody testing

19

What is the gold standard for HIV screening?

ELISA

20

How is the diagnosis of HIV confirmed?

1) HIV-1 Western Blot
2) Multispot HIV-1/HIV-2 test

21

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

HIV RNA PCR

22

What are the current screening recommendations for HIV screening?

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

23

When is repeat screening for HIV recommended?

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

24

What are the HIV screening recommendations for pregnant women?

Test all women*

*Law in IA

25

How does HIV-2 differ from HIV-1?

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

*Coinfection is possible

26

What receptors/ co-receptors mediate HIV viral entry?

Receptor= CD4

Co-receptor=
- CCR5
- CXCR4

27

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

CCR5

28

What is a CXCR4 trophism associated with?

Faster progression to AIDS

29

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

gp120

30

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

Interferes with the co-receptor for HIV
- Heterozygous= slow progression to AIDS
- Homozygous= v. challenging to get infected with HIV