HIV

Question 1

Pathology

Answer 1

HIV binds to CD4
-Depletion and impaired function of CD4+ cells →
immune dysfunction

Question 2

Virology

Answer 2

ssRNA retrovirus
1. After entry, viral reverse transcriptase makes DNA
copy of viral RNA genome.
2. Viral integrase enzyme integrates this with host DNA
3. Core viral proteins synthesised by host and then cleaved by viral protease into mature subunits
4. Completed virions released by budding

Question 3

Acute infection

Answer 3

Normally asymptomatic
Transient illness 2-6wks after exposure
Fever, malaise, myalgia, pharyngitis, macpap rash

Question 4

AIDS

Answer 4

AIDS

Question 5

Diagnosis

Answer 5

ELISA: detect serum (or salivary) anti-HIV Abs
Western Blot: for confirmation
PCR: can detect HIV virions Rapid Antibody Tests: results should be confirmed by Western Blot

Question 6

Stages

Answer 6

Stage 1:
- Primary infection - Cd4+ > 500 cells - asymptomatic

Stage 2:
Latent infection - Cd4+ < 500 cells - mild symptoms

Stage 3:
Symptomatic infection- Cd4+ < 350 cells - advanced symptoms

Stage 4 AIDS- cd4+ < 200 cells - HIV or AIDs - severe symptoms

Question 7

AIDs defining illnesses

Answer 7

Kaposi’s sarcoma - vascular neoplasm caused by herpes
Pneumocystis Pneumonia - pneumocystis jiroveci fungus
Oral candidiasis

Question 8

Testing

Answer 8

Opt out approach

Question 9

HAART

Answer 9

2 x nucleoside reverse transcriptase inhibitors
AND 1 :
• Non-nucleoside reverse transcriptase inhibitor
• Protease inhibitor
• Integrase inhibitor
• CCR5 inhibitor

Question 10

When to give HAART

Answer 10

As soon as possible

Question 11

HIV exposure

Answer 11

Post-needle-stick = 0.3% (1/300)

• Report to occupational health
• Immunise against hep B (active + passive)
• Test blood from both parties: HIV, HBC, HCV
• Repeat recipient testing @ 3 and 6mo

Question 12

PEP

Answer 12

Post exposure prophylaxis

• In high-risk exposure from HIV + or unknown source.
• Start ASAP
• Continue for at least 28d