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Neoplasia Block > IID: HIV/AIDS 1-3 > Flashcards

IID: HIV/AIDS 1-3 Flashcards

1
Q

What is p24 (Gag) antigen in blood a marker of?

A

HIV

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2
Q

What are some main opportunistic infections/pathogens assoc with HIV/AIDS?

A

Kaposi’s sarcoma
PCP
Candida

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3
Q

Another hallmark of HIV/AIDS (cell count)

A

LOW WBC COUNT!

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4
Q

What is the defining feature of a retrovirus and what can it do?

A

RT, which can convert RNA to DNA

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5
Q

Which viruses (and genus) cause AIDS?

A

HIV1/2, in the Lentivirus family

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6
Q

What do simple retroviral gag pol and env encode? (genes)

A 
gag-core viral prot
pol-RT
env-envelope prots
-LTRs control prot expr (long tandem repeats on virus)
-complex retrovirus has more genes
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7
Q

What are some genes in oncogenic viruses

A

v-rel: allows for modification of host chrom, causing malig

src: encoded by some viruses and causes cancer (cell signaling pathways) (eg in RSV, rous sarcoma virus)

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8
Q

Human-T-cell leukemia virus (HTLV-1)

A

-complex virus with icosahedral core, doesnt actually contain an oncogene but DOES cause cancer esp adult t-cell leuk/lymphoma (ATLL) (so carriers of this virus have a lil chance of getting ATLL)
ATLL: affects CD4+ cells, asia/africa/carib middle aged
IV drug users
no vaccines (***non HIV retroviruses are lower yield)

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9
Q

MMTV

A

mouse mammilary tumor virus
complex retrovirus w vertical germline parent to child transmission or hz thru breastmilk (sometimes HMTV found in ppl w BC)

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10
Q

Why does HIV often lead to cancers?

A

bc of immunsuppression, so pt cannot conduct normal tumor survellience

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11
Q

Where is it thought that HIV-1 originated

A

bush meat (monkeys, from SIVcpz)

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12
Q

HIV-1 virus description (env)

A

most widespread HIV strain
ENVELOPED retrovirus in the LENTIVIRUS family (env has glycoprots to attach to host cells)
Viral RNA enclosed in capsid

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13
Q

What ENZYMES does HIV-1 virus contain

A
  • RT (makes dna copy of viral rna genome)
  • integrase (integrates dna copy of viral genome into host dna, so viral mRNA and prot can be produced)
  • protease: processes precursors to viral proteins
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14
Q

What cells does HIV mainly affect?

A

CD4+ T-cells! (weakens immune sys, and overtime can cause AIDS)

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15
Q

Why is not everyone who comes in contact with HIV affected by the virus?

A

not that stable, bc attachment prot gp120 is shed fast

-since enveloped, sensitive to heat drying etc

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16
Q

what bodily fluid is HIV NOT transmitted thru

A

NOT transmitted thru saliva (has proteases that inactivate virus)/tears/sweat

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17
Q

How does a retrovirus attach?

CD4, gp120, gp41

A

virus attaches to CD4 on host cell via gp120 on its own envelope (CD4 is on T cells macros and microglia in brain, causing CNS sx). after binding, coreceptors cause gp41 to be rel from virus, which inserts into host cell memb and holds them together so membrane fusion can occur

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18
Q

RETROVIRAL ENTRY AND REPLICATION

A

Once virus enters cytoplasm, it uncoats.
Each RNA copy (2 per virion) produces a double stranded DNA copy of the RNA via RT. (i.e., goes from viral RNA to DNA).
Then this DNA is integrated into host DNA via enzyme integrase.
Then this viral DNA is transcribed into mRNA and translated into protein (the regular way)
-Then new viral particles are asembled and released from cell as immature (noninf) particles, and protease matures them to be infectious.

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19
Q

HIV/AIDS clinical course if untreated:

A

Patient infected by virus, increases viral RNA, and decreases CD4+ cells (primary infection).
Then during clinical latency, immune sys kicks in, decreases HIV RNA in blood and slightly incr T-cells.
Virus wins out, and CD4+ drops drastically (viral load incr).–this means pt has AIDS (high risk for opp infxns)

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20
Q

HIV/AIDS clinical course if treated with HAART (anti-retroviral tx)

A

Same primary stage
Drive RNA viral load very low, and can maintain CD4+ to only SLIGHTLY lower than normal
Can have relatively normal lifespan!

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21
Q

What diseases is characterized by consistently low CD4+ T-cell count?

A

AIDS (almost always found in ppl infected with HIV virus, has ab’s against HIV)

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22
Q

High vs low levels of HIV viruses predicts?

HAART predicts?

A

high vs low risk of dev AIDS
w/ HAART, low risk of dev AIDS bc low viral load
(children born to HIV infected mothers can also get AIDS)
-HIV being cause of AIDS follows Kochs postulates (criteria for det whether certain factor causes disease)

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23
Q

How does HIV kill CD4+ cells?

A

lots of ways, incl necr/apop, fusion, G2 cell cycle blockade, TAT EFFECTS (tat is prot encoded by HIV-1 that increases viral transcription), rel to affect bystander cells
Dropping CD4+ count causes AIDS

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24
Q

4 opportunistic infections seen mostly in AIDS

A

PCP (pneumonia), have drugs now, crushed ping pong ball histo
Mycobacterium avium
Candida
HHV-8 (Human Herpes Virus 8) which causes Kaposi’s sarcoma

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25
Q

Which virus causes Kaposi’s sarcoma?

A

HHV-8

26
Q

Commonly used tests for HIV infection, and window periods?

A

ELISA immunoassay- 16-25d
oral rapid
western blot 25d
flow cytometry (checks CD4+ count but not HIV necessarily)
NAT (nucleic acid test) measures viral load, 12d
Genotyping to detect viral mut that result in resistance to HAART
(shortest seems like NAT?)

27
Q

How specific and sensitive is current HIV testing?

A

> 99%!

but false positives can occur with SLE, ab’s to other infections etc

28
Q

Some examples of HIV treatments, and how they can affect certain steps in HIV infectious process

A

Fusion inhibitors prevent viral attachment
RT inhibs prevent HIV RNA from being conv to DNA to be int into host genome
INtegrase inhibs prevent integration of viral DNA from RT into host
Tat antagonists can decr HIV transcription from Tat so decr amount of virus particles transcribed to be rel
Protease inhibs can decr amount of active/mature viruses that have been released

29
Q

Why is there no vaccine for HIV?

A

HIV is enveloped w glycosylated glycoprots that arent good epitopes
Virus mutates quickly to avoid immune resp
Thousands of strains

30
Q

Does HIV encode an oncogene?

A

NO!!!

but some other retroviruses do

31
Q

Screening recommendations for HIV

A

screen adults age 15-65 (and outside this range if at incr risk), for v high risk can screen anually (eg MSM, IVDU, sex workers, unprotected sex, all pregnant women)
-ART can also prevent transmission to other ppl bc decr viral load

32
Q

What disease states incr urgency for ART use?

A 
HIV assoc conditions (malig, dementia, nephro)
OIs
lower cd4+ count
co-inf with HBV or HCV
acute/early infxn
33
Q

Types of current ART meds?

A

RT inhibs (nucleoside aka NRTIs and non-nucleoside)
Protease inhibs
Integrase inhibs
(recommend 2 NRTIs + smth else)

34
Q

Predictors of inadequate adherence to HAART

A 
regimen complexity
literacy/pt educ
drug/alc use
mental health issues
sxe and fatigue
35
Q

HAART how often to check CD4+ and Viral load count

A

check viral load count more often

viral load decr a lot (want to get to <200), and CD4+ incr gradually

36
Q

Leading cause of OI (opportunistic infection) death globally?

A

TB!!!

isoniazid + rifa

37
Q 
How to prophylatically treat OIs with CD4 counts of:
-any
<200 /thrush/OI history
<100
<50
A

-any: treat TB
<200 treat for PCP, TMP-SMX DS daily
<100 treat for toxoplasmosis: only if toxo igG+, same tx as above
<50 treat for MAC with azithro, (CMV retinitis may occur but no prophylaxis indicated), screen for cryptoccoccal meningitis

38
Q

What diseases should you vaccinate for in ALL pts with HIV/AIDS>

A

Pneumococcus
Influenza injxn
Tetanus/ Dipth/ pertussis (TDaP)
Meningococcus

(SOME may want HAV, HiB, HPV, MMR, Varicella dep on CD4+ count)

39
Q

What is IRIS (iimmune reconstitution syndrome)

A

worsening of preexisting dis after init of HAART, usu just in first few weeks tho

40
Q

who should receive ART?

A

all indivs with detectable HIV load, regardless of CD4+ count

41
Q

What type of vaccine should AIDS/HIV pts NOT receive?

A

live attenuated, bc theyre immunocompromised!

eg dont give HIV pts shingle vaccine bc live!

42
Q

at less than 500 CD4+ in HIV, what infx is most likely to occur?

A

TB! and others

43
Q

At less than 200 in AIDS, what infxn likely to occur

A

CANDIDA ESOPH
PCP
and others

44
Q

What opportunistic infections are likely to occur at less than 100 and less than 50 in HIV?

A

MAC

CMV

45
Q

AIDS defining is CD4+ count of less than…

A

200!

46
Q

how long is HIV avg latency

A

LONG! 10 yr avg

47
Q

Toxoplasma encephalitis cx

A

MULTIFOCAL brain lesions, multiple ring enhancing lesions in periventricular WM of basal ganglia

48
Q

Toxoplasma gondii
sx
cd4 count?
dx

A

protozoan with cats that eat it and poop it out, other animals eat it
sx tissue cysts
CD4<100
dx if MRI lesions, HIV, toxo IgG ab’s, treat pt

49
Q

HHV-8/Kaposi’s sarcoma

CD4 count

A

GREATER than 200!!!

50
Q

What does kaposi’s sarcoma come from

A

HHV-8 after HIV

51
Q

Kaposis sarcoma sx
Dont confuse w
Tx
histo

A

lesions on skin etc, eleph
dont confuse w bartonella
Tx w. chemo
histo: spindle cells on slides

52
Q

who is at risk for cryptococcus neoformans based on CD

A

those w CD<100 (profound immunnosupp)

53
Q

Other sx of cryptoccocus

A

high intracranial pressure
CSF may look normal
skin lesions

54
Q

for cryptococc u take latex aggl of where?

A

CSF (brain and spine)

55
Q

what is oft absent in cryptococc in HIV

A

classic meningeal signs

56
Q

PCP at what cd4 count?

A

<200, or less than 14%, use PROPYLACTIC treatmeant for OIs!

check for toxoplasma if gets to below 100

57
Q

what cells does pcp attach to

A

alveolar and fills them with foamy eosin exudate

58
Q

other pcp sx

what is elev

A 
dry cough (non prod)
LDH elev! and B-glucan
59
Q

Primary prophylaxis for OIs (CD levels) in HIV

A

at less tha 200, uses PCP prophylaxis tx
at less than 100, uses toxoplasma prophylaxis
at less than 50, use MAC prophylaxis

60
Q

Case studies: HIV pts with

1) seizure, motor issue, ring enhancing lesions
2) CD over 200 (and 500), major skin lesions
3) no meningeal signs but has headache, v high intracranial pressure
4) dry cough, HIV+

A

1) toxoplasmosis
2) kaposis sarcoma
3) cryptococcus neoformans
4) PCP

61
Q

What is a main sx in kaposi’s sarcoma

A

SKIN LESIONS!

Neoplasia Block (16 decks)

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