Pod Block 3 - Hiv

Front 1

What is the number 1, most important, key enzyme that HIV has?

Back 1

Reverse transcriptase

Front 2

What is the overall replication pathway of HIV, starting with entry into the host cell?

Back 2

RNA is converted into ssDNA (via reverse transcriptase)
ssDNA is converted into dsDNA
dsDNA is inserted into host chromosomes
Virus uses host polymerase to make new RNA
RNA is packaged into virus.
Virus buds

Front 3

How good is HIV at proofreading?

Back 3

Not good at all!

It is possible for the replicating virus to produce at least one mutation in every one of its 10^4 base pairs every day

Front 4

What are the three gene types found in HIV and what does each one code?

Back 4

GAG - Codes for antigens (capsid)
POL- Codes for viral enzymes
ENV - Codes for the envelope and glycoproteins

Front 5

What are M-topic HIV strains?

Back 5

Early bugs following an infection.
Their reservoir is the macrophage and they bind to CCR5

Front 6

What are T-topic HIV strains

Back 6

Strains of HIV found in later infection (after M-topic strains)
Their reservoir are T cells and they bind to CXCR4

Front 7

What is the clinical significance of CXCR4 and CCR5?

Back 7

HIV needs to bind to these in order to gain entry into the cell. If you can block these, then the bug dies.

Researches are currently working on this

Front 8

What is the half-life of HIV?

Back 8

7.5 hours

Front 9

What year was the official start of the AIDS epidemic?

Back 9

1981

Front 10

What are the major strains of HIV-1?

Back 10

M (major), O (outlier), N (new)

Front 11

What are clades?

Which is the most common in the US?
Which clades are more common in Africa and Asia?
Which clades are most commonly transmitted through heterosexual sex?

Back 11

Substrains of HIV-1-M that infect different cells.

Clades A,B,C are the most common (Clade B is the most common of those)
Clades C & E are more common in Africa
Clades C & E are also the ones transmitted predominantly through heterosexual sex.

Front 12

Where is HIV-2 most prevalent?

Back 12

West Africa

Front 13

Compared to HIV-1, HIV-2 is ___infectious, has a ___ progression and is ___ resistant to NNRTI's.

Back 13

Compared to HIV-1, HIV-2 is LESS infectious has a SLOWER progression, and is MORE resistant to NNRTI's.

Front 14

In which region of the world is the number of people living with HIV on the decrease?

Back 14

Trick question - The number of people living with HIV is on the rise everywhere in the world

Front 15

Why is the number of people living with HIV on the rise?

Back 15

Two reasons:
1. Better diagnosis
2. Better treatments mean more people are living longer

Front 16

What does HIV protein GP120 do?

Back 16

Binds to the surface of the host cell

Front 17

After how many STD's should a person get tested for HIV?

Back 17

After 1.

Actually, everyone who is sexually active should get tested.

Front 18

What is the most common mode of transmission of HIV in males?

Back 18

Male-to-male sexual contact

Front 19

What is the most common mode of transmission of HIV in females?

Back 19

Heterosexual contact

Front 20

Your friend, Johnny gets around. He brags about the number of different partners he's had and thinks condoms are for weenies. He even brags that he recently had sex with a female known to have HIV.
When you ask if he's concerned about getting HIV, he tells you that according to a chart he read, the risk is only 5 in 10,000.
What's the problem with his justification?

Back 20

The risk could be much higher (or lower) depending on many different factors including viral load.

Front 21

Which has a higher rate of transmission (all else being equal)
Male-to Female, or Female-to Male?

Back 21

Male-to-Female is higher

Front 22

Three important enzymes that HIV carries with it to facilitate replication:

Back 22

Reverse transcriptase, protease, integrase

Front 23

What is the length of the latent period for HIV?

Back 23

Can be as short as 1-2 years, or as long as 15 years

Front 24

From the time of infection, how long does it take for ELISA tests to become reliable?
What about for western blot?
What determines these time lengths?

Back 24

Takes about 3 months for a test to be reliable.
Same for western blot.
Based on the length of time it takes a person to seroconvert.

Front 25

Do all HIV tests now check for both HIV-1 and HIV-2?

Back 25

No… ELISA and PCR do, but western blot only tests for HIV-1

Front 26

With the exception of rapid testing, which HIV test is TYPICALLY done first in the clinic?

A. PCR
B. Western blot
C. ELISA

Back 26

C. ELISA

Front 27

Name four conditions besides HIV that could lower a person's CD4 count.

What does this imply clinically?

Back 27

Stress, Illness, Steroids, Idiopathic causes

Implies you can't use CD4 counts to diagnose HIV

Front 28

In the analogy of the train heading towards a cliff, which indicator represents how far the train if from the cliff, and which indicator represents how fast its going?

Back 28

How far = T-cell count
How fast = Viral load

Front 29

Indicators for HIV therapy (6):

Back 29

HIV-associated nephropathy
Treatment for Hep B indicated
CD 4 count < 350
Post-exposure prophylaxis
AIDS defining illness
Pregnancy

Front 30

Five benefits of early HIV therapy:

Back 30

Maintenance of a higher CD 4 cont
Decr. Risk of HIV associated complications that can occur even at higher CD4 levels (>350)
Decr risk of non-opportunistic conditions
Decr. Risk of transmission

Front 31

Risks for early HIV therapy:

Back 31

Side effects
Drug resistance due to incomplete suppression
Less time for a patient to be mentally prepared for adherence
Increased total time on meds
Transmission of drug resistant virus in px who do not maintain full virolgic suppression

Front 32

General side effect of the nuke class:

Back 32

Lactic acidosis

Front 33

Which HIV drug can lead to a very serious hypersensitivity reaction?
What class is this drug in?

Back 33

Abacavir - member of the nuke class

Front 34

General side effect of the NNRTIs

Back 34

Rash

Front 35

Which HIV drug is contraindicated in pregnancy?
Which class is it in?

Back 35

Efavirenz -NNRI

Front 36

What three drugs make up Atripla?

Back 36

EFZ+FTC+TDF

Front 37

Make sure you review your HIV drug flashcards from block 2.

Back 37

Did you do it?

Front 38

Following HIV exposure/infection how long does it usually take to develop acute HIV?

Back 38

Two to six weeks

Front 39

How long does acute HIV last for?

Back 39

May last from a few days to >10 weeks

Front 40

Which illness does acute HIV resemble?

Back 40

Mono

Front 41

Describe the rash that you see in Acute HIV?

Back 41

Maculopapular w/ lesions on the face & extremities (including palms)

Front 42

How can you test for acute HIV?

Back 42

PCR

Front 43

Do you treat someone with acute HIV?

What is a major downside to starting someone on treatment at this point?

Back 43

Treatment is a case-by-case basis.
If you start treatment at this point, the patient will have to be on meds for life

Front 44

What is IRIS? Why does it happen?

Back 44

IRIS = Immune reconstitution inflammatory syndrome

It affects patients who've started antiviral therapy.
Basically, as the immune system improves it begins fighting infections that were dormant before, leading to an inflammatory response

Front 45

Rank the following in order of transmission risk following needle stick:
HIV
HCV
HBV

Back 45

Rule of 3's:
HBV > HCV > HIV

Hint: They're in alphabetical order

Front 46

A very nervous medical student accidentally sticks himself while he is stitching an HIV patient up.
How long can he wait before prophylaxis would be useless?

Back 46

He needs to start ASAP.
The maximum time is within 2-4 hours

Front 47

Steps for post-exposure prophylaxis:

Back 47

Start treatment ASAP.
Use rapid test to check patient source
Treat for 4 weeks
Check HIV at baseline 3 months and 6 months

Front 48

A young woman who is HIV+ recently found out she is pregnant.
When should you not treat her?
Is it ever okay to just treat the patient with 1 drug?
Which drug should be avoided?
When would a C-section be indicated?

Back 48

You should always treat a pregnant woman for HIV.
You can use AZT alone if her viral load is <1000.
You should avoid efavirenz
A C-section is indicated if her viral load is >1000 at 38 weeks?

Front 49

Which opportunistic infection shows a butterfly appearance in the lungs?

Back 49

PCP

Front 50

Which opportunistic infection will show up on a brain MRI as a solitary ring enhancing lesion?

Back 50

Toxoplasmosis

Front 51

Which opportunistic infection do you prophylax at CD4<200? Which drugs do you use for this?

Back 51

Prophylax PCP

Use TMP/SMX or Dapsone

Front 52

Which opportunistic infection do you prophylax at CD4<100? Which drugs do you use for this?

Back 52

Toxoplasma

Use TMP/SMX or Dapsone/pyrimethamine

Front 53

Which opportunistic infection do you prophylax at CDC<50? Which drugs do you use?

Back 53

MAC

Use Z-pack or Rifabutin