HIV

Question 1

HIV

Answer 1

human immunodeficiency virus

Question 2

HIV1 HIV2

Answer 2

HIV1 = retrovirus responsible for most HIV infections
HIV2 = similar illness but has a longer latent period

Question 3

how many people HIV +ve in the world

Answer 3

30 mil
2.5mil/yr
2mil deaths/yr
most in africa

Question 4

Immunology

Answer 4

HIV binds via its gp120 envelope to CD4 receptors on helper t lymphocytes, monocytes, macrophages and neural cells

CD4 +ve cells migrate to lymphoid tissue where the virus replicates = billions of new virions which infect more CD4 +ve cells

impaired function or deletion of CD4 cells = decrease in immune func

Question 5

virology of HIV

Answer 5

RNA retrovirus - 9 subtypes

after cell entry viral reverse transcriptase makes a DNA copy of the RNA genome

viral integrase enzyme then integrates this into DNA host

the core viral proteins are synthesised as polypeptides to make the building blocks of the virus

Question 6

viral load

Answer 6

the number of circulating viruses (viral load) predicts progression to AIDS

Question 7

acute primary infection

Answer 7

seroconversion
transient immunosuppression and fall in CD4 count followed by rise
acute rise in viral load then fall to set point
symptoms: fever, malaise, myalgia, pharyngitis, maculopapular rash

Question 8

phase 2 infection

Answer 8

• asymptomatic phase (years)
  progressive loss of CD4 T cells resulting in poor immunity, clinical latency (+/- progressive generalised lymphadenopathy)
• Early symptomatic HIV (‘AIDs related complex’)

Question 9

phase 3 infection

Answer 9

AIDS!!!
symptoms of immune deficiency
CD4

Question 10

PGL

Answer 10

persistent generalised lymphadenopathy

nodes >1cm diameter and 2 or more extra inguinal sites persisting for >3mo

Question 11

what are AIDs related symptoms?

Answer 11

inc temp
night sweats
diarrhoea
decreased weight
minor opportunistic infection eg oral candida, herpes zoster

Question 12

AIDS CD4 count

Answer 12

CD4

Question 13

HAART

Answer 13

highly active antiretroviral therapy

Question 14

Diagnosis HIV

Answer 14

serum or salivary HIV antibodies by ELISA

Question 15

if recent infection?

Answer 15

HIV-antibodies might be negative
check for HIV RNA (PCR) or core p24 protein antigen in plasma
or repeat ELISA 6w and 3mo

Question 16

which subtypes common in UK

Answer 16

A and B

Question 17

which subtype common in Africa

Answer 17

D

Question 18

which types have a worse prognosis

Answer 18

hybrid / recombinant types as they bind to immune cells more readily

Question 19

HIV prevention

Answer 19

blood screening
disposable equipment
antenatal retrovirals if HIV +ve and C sec bith and bottle feeding
PEPSE - post exposure prophylaxis following sexual exposure
HAART rx as protection
behavioural - sex ed, reduce freq of partner change, condom use

Question 20

TB and HIV

Answer 20

if pt has cough, fever, night sweats or weight loss they have TB until proven otherwise

Question 21

long term non progressors

Answer 21

those infected with the virus but dont get ill as they have alterations in immune system which are protective

Question 22

where does the virus often sit latent for a long time

Answer 22

genital tract
CNS
GI system
bone marrow

Question 23

UN AIDS aim

Answer 23

90/90/90 goals
90% of people living with HIV being diagnosed
90% diagnosed on antiretroviral therapy (ART)
90% viral suppression for those on ART by 2020

Question 24

AIDS

latent period?

Answer 24

acquired immune deficiency syndrome
latent period 5-10 y - HIV2 slower / long term non progressors can be longer
more rapid in rapid progressors, children and elderly

Question 25

red flags for high risk group

Answer 25

fever, rash and non spec symptoms
1 take a sexual hx
2 think of HIV seroconversion illness
3 tell lab check for antigen as well

also if recurrent shingles, candidiasis etc