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Flashcards in HIV I Deck (40)
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1
Q

64% of new HIV infections every year occur in ___.

A

64% of new HIV infections every year occur in Sub-Saharan Africa

2
Q

~70% of new infections of HIV in the US in 2016 were attributed to ___.

A

~70% of new infections of HIV in the US in 2016 were attributed to male-male sexual contact.

3
Q

The highest single-exposure risk for contracting HIV is contact via ___. The second is contact via ___.

A

The highest single-exposure risk for contracting HIV is contact via blood transfusion. The second is contact via vertical transfer (mother to child).

4
Q

The primary viral factor which affects transmission is ___.

A

The primary viral factor which affects transmission is the level of virus in the HIV infected individual

5
Q

Host factors which affect transmission

A
  • Complicating additional STIs (which may cause ulceration or otherwise local susceptibillity to infection)
  • Type of sexual behavior (anal sex risk > vaginal sex risk > oral sex risk)
  • Gender of sexual partners (highest risk M to M, lowest risk W to W)
  • CCR5 variants of individuals involved
6
Q

Most often, the transmitted HIV is . . .

A

Most often, the transmitted HIV is macrophage-tropic HIV (also known as R5 HIV) and this virus preferentially utilizes the CCR5 co-receptor, not the CXCR4 receptor

7
Q

When is antiretroviral post-exposure prophylaxis most effective?

A

Within the first few days of infection, before HIV has a chance to multiply locally

8
Q

Pathway of HIV infection and dissemination

A
9
Q

HIV serology studies

A
10
Q

Symptoms of the early viremic phase of HIV

A
  • malaise,
  • fever,
  • rash,
  • lymphadenopathy,
  • oral ulcers,
  • diarrhea
11
Q

Acute phase of HIV infection is defined as . . .

A

. . . the time between the appearance of HIV RNA and before HIV infection is detectable by immunoassays, lasts between 5 and 40 days after RNA appears. Duration depends on s on the generation of immunoassay used for testing

12
Q

Generations of HIV detection

A
  • 1st generation: HIV IgG, high level, earliest ~50 days
  • 2nd generation: HIV IgG, low levels, earliest ~35 days
  • 3rd generation: HIV IgM, low levels, earliest ~22 days
  • 4th generation: HIV-1 p24 antigen, earliest ~15 days
  • Nucleic acid tests: HIV-1 RNA, earliest ~10 days
13
Q

Recommended HIV testing algorithm

A
14
Q

HIV “window” period

A

when virus is present in the blood, but seroconversion has not yet occurred

15
Q

It is very difficult to diagnose HIV before ___-post infection. If tests come back negative but HIV is still suspected, ___.

A

It is very difficult to diagnose HIV before 15 days-post infection. If tests come back negative but HIV is still suspected, order a serum HIV RNA assay now and have the patient come back in a few days for another protein assay.

16
Q

Natural progression of HIV

A
17
Q

Acute HIV infection may be generally characterized by . . .

A

Acute HIV infection may be generally characterized by a mononucleosis like illness that occurs within weeks after infection

18
Q

Untreated individuals with low viral “set points” progress ___, while untreated individuals with high viral “set points” progress ___.

A

Untreated individuals with low viral “set points” progress more slowly, while untreated individuals with high viral “set points” progress more rapidly.

19
Q

As the level of CD4+ T cells drops below ___, individuals are at increased risk for opportunistic infections.

A

As the level of CD4+ T cells drops below 500, individuals are at increased risk for opportunistic infections.

20
Q

Gut mucosal CD4 T cells in HIV

A

Acute infection is associated with massive depletion of mucosal CD4+ T cells that are typically enriched with cells co-expressing CCR5. This gut mucosal CD4+ T cell depletion can lead to infection and inflammation of the entire bowel.

21
Q

Ways in which HIV chronically stimulates the immune system to create CCR5 fodder

A
  • Direct effects of HIV as a ligand for toll like receptors on plasmacytoid dendritic cells leading to production of interferon-α
  • microbial translocation across the gut and activation of TLR4 leading to the production of pro-inflammatory cytokines
  • co-infection with viruses (eg CMV) leading to CMV specific T cell activation
  • reduced ratio of Thelper-17 and regulatory T cells, especially in the gastrointestinal tract
22
Q

Major groups of antiretrovirals for HIV

A
  • HIV protease inhibitors
  • Reverse transcriptase inhibitors
  • Integrase inhibitors
  • Entry inhibitors
23
Q

Cobicistat

A

Inhibits the hepatic p450 enzyme which metabolizes many antiretrovirals

24
Q

Drug-resistance in HIV. . .

A

. . . develops rapidly when a single antiretroviral is used

25
Q

General principles of antiretroviral therapy

A
  • Everyone receives a combination of at least two active drugs
  • Common regimens include:
    • NRTI plus protease inhibitor
    • NRTI plus integrase inhibitor
    • NRTI plus NNRTI
  • Diagnose as early as possible
  • Start treatment at time and location of diagnosis
  • Protect people at risk
  • Respond quckly to new clusters of HIV cases
26
Q

Approximately ___% of all DNA transcripts produced contain an error due to the lack of proof reading ability by reverse transcriptase

A

Approximately 50% of all DNA transcripts produced contain an error due to the lack of proof reading ability by reverse transcriptase

27
Q

__% of newly infected individuals are unaware of their disease for years before diagnosed.

A

15% of newly infected individuals are unaware of their disease for years before diagnosed.

28
Q

The “Berlin” patient

A
  • Only case known where an individual was cured of HIV
  • HIV positive man that contracted AML
  • He required a bone marrow transplant, relapsed, and was given a second transplant from a donor homozygous for the CCR5 delta 32 mutation
  • This patient remains with no detectable HIV RNA after 9 years on no ART
29
Q

___ with provirus are not susceptible to ART.

A

Resting memory T cells with provirus are not susceptible to ART.

30
Q

Major anatomical reservoires of HIV provirus

A
  • Lymph nodes
  • Thymus
  • MALT
31
Q

A 30-year-old man has receptive anal intercourse with his HIV positive partner for over ten years without infection. He is found to have a homozygous mutation on his CD4 cells. What is likely to explain the mechanism of his apparent immunity to HIV?

A

Impaired viral fusion via gp120 due to mutation in CCR5

32
Q
A

Atypical lymphoctes, characteristic of EBV, CMV, HIV

Not infected, but highly, highly activated CD8+ T cells

33
Q

___, ___, and ___ are clinically indistinguishable in early stages.

A

EBV, HIV, and CMV are clinically indistinguishable in early stages.

34
Q

Innate immune mediator timecourse

A
35
Q
A

Ring enhancing lesions

The lighter-centered one is fluid filled. The borders are lining inflammatory cells.

36
Q

Patients with positive IgG are ___ at risk for toxoplasa

A

Patients with positive IgG are not at risk for toxoplasa

37
Q

Ring enhancing lesions on an HIV patient’s radiograph is usually . . .

A

. . . toxoplasma or B cell lymphoma

38
Q

CNS disease in HIV

A
39
Q

A patient with a CD4 count of 82 starts on HAART and returns a month later with acutely worsening symptoms but a CD4 count of 250. What is the likely diagnosis?

A

Immune reconstitution inflammatory syndrome (IRIS)

40
Q

If CD4 is <200, prophylactic ___ is recommended to prevent ____.

A

If CD4 is <200, prophylactic bactrum is recommended to prevent toxoplasmosis and pneuocystis jirovecii.