FN: HIV

Question 1

Immunology

Answer 1

1. HIV binds via gp 120 to CD4 - Th cells, monocytes, macrophages, neural cells
2. CD4+ cells migrate to lymphoid tissue where virus replicates –> infectino of new CD4+ cells
3. Depletion and impaired function of CD4+ cells - immune dysfunction

Question 2

Virology

Answer 2

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

Question 3

Natural Hx

Answer 3

1. Acute infection: usually asympto
2. Seroconversion
3. Asymptomatic infection

Question 4

Seroconversion

Answer 4

1. Transient illness 2-6 wks after exposure
2. Fever, malaise, myalgia, pharyngitis, macpap rash
3. Rarely meningoencephalitis

Question 5

Asymptomatic infections

Answer 5

But 30% will have PGL

• Notes >1 cm in diameter
• > 2 extra-inguinal sites
• > 3mo

Question 6

AIDS related Complex

Answer 6

1. AIDS prodrome
2. Constitutional symptoms: fever, night sweats, wt. loss
3. Minor opportunistic infections
   - Oral candida
4. Oral hairy leukoplakia (EBV)
5. Recurrent HSV
6. Seborrhoeic dermatitis

Question 7

AIDS

Answer 7

Defining illness

CD4 usually

Question 8

OTher effects of HIV

Answer 8

1. OSteoporosis
2. Dementia
3. Neuropathy
4. Nephropathy

Question 9

Diagnosis

Answer 9

1. ELISA: detect serum (or salivary) anti-HIV abs
2. Western Blot: for confirmation
3. PCR: can detect HIV virions in the windown period
4. Rapid antibody tests: false positives are a problem and results should be confirmed by western blot

Question 10

Recent exposure window for diagnosis

Answer 10

Usually 1-3 wks

Can be 3-6 months

Question 11

Investigations

Answer 11

1. HIV diagnostic tests
2. Drug resistance studies e.g. genotyping for reverse transcriptase or protease mutations
3. Mantoux test
4. Serology: toxo, CMV, HBV, HCV, syphilis

Question 12

Monitoring

Answer 12

CD4 count
Viral load (HIV RNA)
FBC, U+E, LFTs, lipids, glucose

Question 13

HAART indications

Answer 13

CD4

Question 14

REgimens

Answer 14

1 NNRTI + 2 NRTIs

PI+ 2 NRTIs

Question 15

1 NNRTI + 2 NRTIs

Answer 15

NNRTI - efavirenz
NRTI - emtricitabine + tenofovir (Truvada)
Atripla - efavirenz + emtricitabine + tenofovir

Question 16

PI + 2 NRTIs

Answer 16

PI = lopinavir (+ low dose ritonavir = kaletra)

Question 17

Aim of Regimens

Answer 17

1. Undetectable VL after 4mo
2. If VL remains high despite good compliance
   - Change to a new drug combination
   - Request resistance studies

Question 18

Prophylaxis

Answer 18

CD4

Question 19

HIV exposure

Answer 19

1. Seroconversion post-needle-stick = 0.3% (1/300)
2. Report to occupational health
3. Immunise agaisnt hep B (active + passive)
4. TEst blood form both parties: HIV, HBC, HCV
5. Repeat recipient testing @ 3 and 6mo

Question 20

Pep start and used for

Answer 20

Start PEP in high-risk exposure form HIV+ or unknown source

Start ASAP as possible
Continue for at least 28d
E.g. Truvade + Kaletra