HIV

Question 1

What is HIV?

Answer 1

A retrovirus that infects and replicates in human lymphocytes and macrophages, causing immune deficiency and susceptibility to opportunistic infections and malignancies

Question 2

How is HIV transmitted?

Answer 2

via open cuts and sores, breaks in skin , mucous membranes e.g. anus and vagina, direct injection e.g. PWID, mother to child

Question 3

How does HIV replicate?

Answer 3

HIV infects cells and causes direct killing, apoptosis of uninfected bystander cells, and killing of infected cells

Integrase, reverse transcriptase, and protease enzymes are involved in replication

Question 4

What is HIV latency?

Answer 4

The asymptomatic period between HIV infection and AIDS. HIV never stops replicating, eve when patients feel well.

Question 5

What are Sx of HIV?

Answer 5

Quite general. Weight loss, night sweats, low grade fever, fatigue, rash

Oral ulcers, angular chelitis, oral hairy leukoplakia are common, rash

Constitutional upset e.g. candida infections (thrush), diarrhoea

Question 6

What are Sx at each clinical stage of infection?

Answer 6

Stage 1 = asymptomatic, some lymphadenopathy

stage 2 = recurrent RTI, <10% weight loss, HZV, oral ulecration, angular chelitis, fungal nail infections, seborrhoeic dermatitis

stage 3 = >10% weight loss, PUO, oral hairy leukoplakia, oral candidiasis, TB, anaemia

stage 4 = PCP pneumonia, oesophageal candidiasis, Kaposi’s sarcoma, CMV, HIV encephalopathy, toxoplasmosis, multifocal leukencephalopathy, lymphoma,

Question 7

What Ix in HIV?

Answer 7

HIV tests:

• ELISA test for antibodies. Will not detect immediately after infection.
• POC (rapid)
• PCR. More expensive antibody test
• CD4 cell count indicated immune status, staging, and used to decide when to start prophylaxis against infections. Risk if <200
• HIV viral load. Measured at diagnosis, prognostic.
• drug resistance testing

OTHER

Bloods: CRP, WCC, hepB and C should be checked too

CXR if chest Sx: PJP pneumonia, check if TB

CT

Question 8

DDx for HIV?

Answer 8

Infectious mononucleosis
secondary syphilis
drug rash
viral infection: CMV, rubella, influenza, parvovirus

Question 9

Rx for HIV?

Answer 9

Now recommended to start everyone on treatment despite CD4 count

Usually 2 reverse transcriptase inhibitors e.g. tenofovir and 1 drug from another class

need good adherence to prevent drug resistance

SE: rash, hypersensitivity, sleep disturbance

Question 10

What prophylactic medications should be given for HIV?

Answer 10

Against

Question 11

How can HIV be prevented?

Answer 11

Safe sex

Post-exposure prophylaxis: ART after potential HIV exposure which can be given up to 72 hours after HIV exposure for 28 days (tenofovir) then test 8-12 week later

Pre-exposure prophlaxis: ART in those at high risk e.g. serodifferent relationships condomless anal sex in MSM

Pregnant women with HIV should start ART by 24 weeks gestation, with neonatal PEP given for 4 weeks

Question 12

How does pneumocystis jirovecii present and how is it treated?

Answer 12

SOB on exertion, malaise, dry cough. CXR shows perihilar infiltrates but can be normal, and induced sputum or BAL with staining or NAAT needed for diagnosis

Give IV co-trimoxazole for 3 weeks

Question 13

What are complications of HIV?

Answer 13

AIDS

• pneumocystic jirovecii pneumonia
• CMV

Question 14

what are different drug types used in HIV?

Answer 14

reverse transcriptase inhibitors (NRTI) e,g, tenofovir, emtricitabine

protease inhibitors e.g. atazanavir

NNRTI rilpivirine

integrase inhibitor (INSTIs) dolutegravir