HIV Flashcards
where do HIV origionate from
generally chimpanzee and western gorrilla
thought to be first in humans in 1913-1930 but detected much later
epideamiology of HIV
40 million with HIV
1.3 mil diagnosed a year
630000 die from aids related illnesses
majority are southern africa
71% are virally suppressed now.
100 000 in the uk, 6000 dont know they have it. 99% acessing treatment
discuss cd4 counts.
cd4 cell count at diagnosis is important - if high at diagnosis it is a good sign you will live normal life.- subset of T helper cells. live in lymph nodes usually.
normal is 450+ - infection lowers this. if ower than 200 then AIDS is there.
mortality can be 13x greater.
viral counts rise significanctly, then go down to a set point at about 9 weeks. ( everyones is different)
more gradual decline in CD4. indicator conditions occur at 350. avg 8 years for this to happen.
diagnosis of HIV + S+S
get hiv antigens in the blood- done routinely
p24 antigen- appears at day 16 - then goes to very low levels.
seroconversion day 7-21
HIV antibodies- average 25 days.
4th gen tests should pick up at 4 weeks. otherwise can be tricky to test for as different things occur at different times.
1/3 of people dont get symptoms
generally they are non specific.
- get ‘indicator conditions’ - shingles etc stuff that comes when immune system a bit run down
routine testing reccomended- any sexual health treatment
routinely offer in drug dependency + pregnancy + other blood bourne viruses
in high preavalence areas (>5:1000) on all ED attendances.
natural history of HIV
virus - attatches to CD4 receptor cell- needs co receptor CCR5 or CXCR4.
uncoating
reverse transcrpition
intergrated into host genome (Cd4)
nuclear export of viral proteins
budding
maturation
treatments of hiv
can target every stage
but reverse transcription, intergration and maturation are the most common targets
try and do 1-2 different ways.
reverse transcriptase inhibitor (1 or 2)
plus a non nucleoside reverse transcriptase inhibitor/ protease inhib/ integrase inhib.
mostly down to 1 tablet, can do injections.
antiretrovirals- a big pain for drug/drug interactions.
discuss prevention of transmission of hiv
either one tab a day
or on demand- 2 tabs at least 2 hrs before sex, then one a day untill 48 hrs after the sex.
partner 2 study- no transmission if there is an undetectable viral load.
complications of hiv
peri-hylar haze on cxr.
pcp
pneumatoceles
pneumothoraces
exertional sp02 drop
toxoplasmosis
kaposi sarcoma- Human herpes virus 8.
to ix pcp- induced deep alveolar sputum.
exclude tb
cd4 under 200 gen
Rx: co-trimoxazole 120ml/kg 3/7 then 90mg/kg for 18 days
pred.
definition of AIDS
CD4 count below 200 along with a AIDS defining disease
(PCP, kaposis, toxoplasmosis, cryptococcosis, lymphoma)
overview of PCP + toxoplasmosis
Pneumocystis jirovecii
dry non prod couch, no chest pain, SOB + exercise desat.
CXR- central hazinesss
Mx- co-trimexazole +/- steroids.
Toxoplasmosis- a space occupying lesion.
Ix: MRI with contrast
Mx: Sulphadiazine + pyrimethamine + folinic acid
kaposis sarcoma info
nodular firm lesions either on the skin or viscerally, very vascular and bleed easily
excessive spindle cell production with eldothelial links
lesions often involve mucocutaneous sites, but can be found in lymph areas.
if on the palate they are likely to be visceral lesions.
Rx is HIV rx really, can have chaemo or radio if that does not work.
diagnosed clincally and then with skin biopsy or fine needle lymph aspirate.
structure of HIV virus
p17- cancer causing gene
what is MAC
mycobacterium avioses
found in water sources
causes: 3 main ones
pulm diseases
cervical lymphadenitis
hypersensitivity pneumanitis (hot tub related)
GI route is most common routre of contagon
antimicrobacterial treatment is the cornerstone of Rx. Rifampicin (but monitor liver very closely)
diagnosis- sputum or tissue biopsy.
