L13 - HIV

Question 1

Just read this answer

Answer 1

Acute - influenza - virus replicates and this results in the death of the host cell -> no more virus
Latent - caused by herpesviruses and retroviruses. Viral genome incorporated into cells and causes problems for second time when reactivated
Chronic - Virus particles continue to be shed after the acute period, tebd to only result in disease after a long time

Question 2

What kind of virus is HIV?

Answer 2

A ssRNA retrovirus (latent), uses reverse transcripatse to incorporate itself into the hosts genome

Question 3

Name two ways in which HIV is transmitted

Answer 3

Sexual contact/blood (IV drugs/needlestick)/vertical transmission

Question 4

Give some examples of factors which affect the transmission of HIV

Answer 4

Type of transmission/viral load/use of condoms/breaches of skin or mucosa/anal intercourse/sexual assault

Question 5

What are the symptoms in the acute stage of infection of HIV?

Answer 5

lymphadenopathy/diarrhoea/chronic fevers/night sweats/weight loss/regular opportunistic infections

Question 6

What are some symptoms of the chornic phase of HIV (AIDS) when the CD4 count is below 200?

Answer 6

Kaposi’s sarcome (skin lesions)/PCP (funfal infection of lungs)/thrush in mouth/malignancies

Question 7

What are the initial investigations you would carry out on a patient you expect has HIV?

Answer 7

Serology for HIV antigen/antibody (results will only be +ve four weeks after infection)/CXR/ Tests depend on presentation

Question 8

What test would be used to confirm a HIV diagnosis?

Answer 8

HIV PCR

Question 9

Is HIV more prevelant in homosexuals or heterosexuals in the UK?

Answer 9

Homosexual men

Question 10

Which cells does HIV infect?

Answer 10

CD4+ T lymphocytes

Question 11

Everyone should be tested in a population where HIV is more prevelant than 2/1000 BUT patients presenting with what diseases should in particular be tested?

Answer 11

TB/bacterial pneumonia/meningitis/cancers/unexplained haemotoligcal abnormalities

Question 12

The ‘treatment’ for HIV is the use of 3 anti-retrovirla drugs. Two nucleoside reverse-transcriptase inhibitors and one of another class e.g. protease inhibitor/integrase inhibitor. Give an example of a nucleosdie reverse transcriptase inhibitor

Answer 12

Tenofovir/emtricitabine/lamivudine/abacavir/zidovudine

Question 13

AIDS can cause complications such as brain abcesses, what other diseases could cuase this?

Answer 13

Cancer/TB loads.

Question 14

What staining of bacteria indicates TB?

Answer 14

Acid-fast staining (they are acid fast bacilli)

Question 15

What are the chances of vertical transmission of HIV?

Answer 15

15-45% increases if baby was breastfed by a HIV positive Mother