HIV

Question 1

What is the structure of HIV?

Answer 1

Diploid genome - 2 molecules of +ssRNA, enveloped

Question 2

What are the three structural genes of HIV?

Answer 2

env, gag, pol

Question 3

What does env code for?

Answer 3

gp120 and gp41: Formed from cleavage of gp160 to form envelope glycoproteins

Question 4

What does gp120 do?

Answer 4

Docking glycoprotein- Attaches to host CD4+ T cell

Question 5

What does gp41 do?

Answer 5

Transmembrane protein that Fusion and entry into host cell

Question 6

What does gag code for?

Answer 6

p24 - capsid protein

Question 7

What does pol code for?

Answer 7

reverse transcriptase; synthesizes dsDNA from genomic RNA, which then integrates into host chromosome

Question 8

What does HIV bind?

Answer 8

CD4 as well as coreceptor - CCR5 on macs (early infection), CXCR4 on T cells (late infection)

Question 9

What protein mutation can confer immunity to HIV infection?

Answer 9

CCR5. Homozyg = immune. Heterozyg = slower course.

Question 10

What are tat and rev?

Answer 10

Two regulatory genes required for transcription.

Question 11

What is the ELISA test forHIV used for?

Answer 11

Presumptive diagnosis - it is a rule-out test, a sensitive test with a high false positive rate and a low threshold.

Question 12

What is Western blot assay for HIV used for?

Answer 12

Rule in test - Specific, low false-positive rate, and high threshold.

Question 13

What is viral load used for?

Answer 13

Monitor effect of drug therapy. High viral load associated with poor prognosis.

Question 14

What is the cutoff for immuncompromised, and for AIDS?

Answer 14

Immunocomp: CD4+ < 400

CD4+ < 200, CD4+ % <14, or HIV+ with AIDS-defining illness eg Pneuomocystis

Question 15

When may ELISA/Western blot be falsely negative?

Answer 15

First 1-2 months of infection.

Question 16

When may ELISA/Western blot be falsely negative?

Answer 16

Babies born to infected mothers; anti-gp120 crosses the plasma.

Question 17

What is the presentation of candida albicans in HIV+ with CD4 <500?

Answer 17

Oral thrush

Question 18

What are the associated findings of candida in HIV+?

Answer 18

Scrapable white plaque, pseudohyphae on microscopy

Question 19

What the presentation of EBV in HIV+ < 500?

Answer 19

Oral hairy leukoplakia

Question 20

What are the associated findings of EBV in HIV+ < 500?

Answer 20

Unscrapable white plaque on lateral tongue

Question 21

What the presentation of Bartonella in HIV+ < 500?

Answer 21

Bacillary angiomatosis

Question 22

What are the associated findings of Bartonella in HIV+ < 500?

Answer 22

Biopsy with neutrophilic inflammation

Question 23

What the presentation of HHV-8 in HIV+ < 500?

Answer 23

Kaposi Sarcoma

Question 24

What are the associated findings of HHV-8 in HIV+ < 500?

Answer 24

Biopsy with neutrophilic inflammation - spindle cells

Question 25

What the presentation of Cryptosporidum spp in HIV+ < 500?

Answer 25

Chronic, watery diarrhea

Question 26

What are the associated findings of Cryptosporidum spp in HIV+ < 500 ?

Answer 26

Acid-fast oocysts in stool

Question 27

What the presentation of HPV in HIV+ < 500?

Answer 27

Squamous cell carcinoma, commonly of anus (men who have sex with men) or cervix (women)

Question 28

What the presentation of toxoplasma gondii in HIV+ < 200?

Answer 28

Brain abscesses - multiple ring enhancing lesions on MRI

Question 29

What is the presentation of HIV itself with CD <200?

Answer 29

Dementia (ok?)

Question 30

What is the presentation of JC virus reactivation with CD <200?

Answer 30

progressive multifocal leukoencephalopathy

Question 31

What are the associated findings of JC virus reactivation with CD <200?

Answer 31

Non-enhancing areas of demyelination

Question 32

What is the presentation of Pneumocystis jirovecci CD <200?

Answer 32

Ground glass opacities on CXR

Question 33

What is the presentation of Aspergillus with CD <100?

Answer 33

Hemoptysis, pleruritic pain - cavitation or infiltrates on chest imaging

Question 34

What is the presentation of Cryptococcus with CD <100?

Answer 34

Meningitis

Question 35

What are the associated findings of Cryptococcus with CD <100?

Answer 35

Thickly encapsulated/budding years on India ink stain

Question 36

What is the presentation of Candida with CD <100?

Answer 36

Esophagitis - white plaques on endoscopy, yeast and pseudohyphae on biopsy

Question 37

What is the presentation of CMV with CD < 100?

Answer 37

``` Retinitis Esophagitis Colitis Pnuemonitis Encephalitis ```

Question 38

What are the associated findings of CMV with CD < 100?

Answer 38

retinitis - cotton wool spots/extensive hemorrhage esophagitis - linear ulcers bx - cells w/ intranuclear (owl eye) inclusions

Question 39

What is the presentation of EBV with CD < 100?

Answer 39

B-cell lymphoma - Non-Hodgkin, CNS lymphoma

Question 40

What are the associated findings of EBV with CD < 100?

Answer 40

CNS lymphoma - ring enhancing, may be solitary (vs toxo)

Question 41

What is the presentation of Histoplasma capsulatum with CD < 100?

Answer 41

Fever, weight loss, fatigue, cough, dyspnea, nausea, vomiting, diarrhea

Question 42

What are the associated findings of Histoplasma capsulatum with CD < 100?

Answer 42

Oval yeast cells within macrophages

Question 43

What is the presentation of Mycobacterium avium-intracellluare with CD < 100?

Answer 43

Non-specific systemic symptoms - fever, night sweats, weight loss, or focal lymphadenitis