HIV

Question 1

Describe HIV structure

Answer 1

ssRNA retrovirus

Question 2

How can HIV be transmitted?

Answer 2

• unprotected sex
• vertical transmission
• infection of HIV positive bodily fluids *e.g. needle sharing, blood splashed in an eye)

Question 3

How can you prevent HIV transmission during birth?

Answer 3

Dependent on the mother’s viral load:
- <50copies/ml: normal vaginal delivery
- >50copies/ml: consider pre-labour C section
- over 400copies/ml: pre-labour C section recommended.
.
- IV zidovudine given during labour + delivery if viral load is unknown or >1000copies/ml
.
- prophylaxis for the baby: zidovudaine, lamivudine + nevirapine for 4 weeks

Question 4

What are the two forms of prophylaxis for HIV?

Answer 4

• PrEP: truvada (emtricitabine/tenofovir)
• PEP: truvada (emtricitabine/tenofovir) and raltegravir for 28 days

Question 5

How does HIV infect the cell?

Answer 5

• infects with CD4 surface receptor
• replicates inside the cell > kills the cell > inflammation > infects more cells

Question 6

Symptoms of HIV

Answer 6

• fever
• weigh loss
• malaise
• headache
• thrush
• rash
• N+V
• sores in mouth

Question 7

Diagnosis of HIV

Answer 7

• nucleic acid test (PCR)
• antigen/antibody test (serology)
• antibody rapid tests

Question 8

When do AIDs defining illnesses occur?

Answer 8

when CD4 count drops <200 which allows for opportunistic infections + malignancies to occur

Question 9

Examples of AIDs defining illnesses

Answer 9

• TB
• Kaposi’s sarcoma
• pneumocystis jirovecii pneumonia PCP
• candidiasis
• lymphomas
• cytomegalovirus infection

Question 10

What do patients with a CD4+ count of <200 need + why?

Answer 10

co-trimoxazole OD as primary prophylaxis for PCP

Question 11

What do patients with a CD4+ count of <50 need + why?

Answer 11

• azithromycin once weekly to protect against mycobacterium avium-intracelluare infection
• ophthalmology assessment with dilated fundoscopy to look for evidence of intra-ocular infections

Question 12

Baseline investigations for all patients with newly diagnosed HIV

Answer 12

• confirmatory HIV test
• CD4 count + viral load
• HIV resistance profile
• HLA B*5701 status
• serology for syphilis, hep A/B/C
• IgG for measles, varicella, rubella + toxoplasma
• FBCs, U&Es, LFTs, bone + lipid profile
• annual cervical cytology for women

Question 13

Monitoring of HIV

Answer 13

_CD4 count_
- normal: 500-1200 cells/mm^3
- risk of AIDs defining illnesses: <200cells/mm3
.
_viral load_
- testing for HIV RNA per ml of blood
- undetectable: 20 copies/ml

Question 14

Treatment of HIV

Answer 14

combination antiretroviral therapy:
two NRTIs e.g. truvada (tenofovir + emtrictabine) + a 3rd agent e.g. bictegravir

Question 15

Aims of HIV treatment

Answer 15

normal CD4 count (500-2000)
undetectable viral load (<20)

Question 16

What vaccinations should someone with HIV have?

Answer 16

• hepatitis B
• pneumoccous
• flu
• avoid live vaccines e.g. BCG