HIV Flashcards
what type of virus is HIV?
an RNA retrovirus
what enzyme do retroviruses use to replicate?
reverse transcriptase
what are the two broad groups of HIV?
HIV 1
HIV 2
what group of HIV is responsible for the global epidemic?
HIV 1 group M
how long does it take for a new generation of HIV to be produced?
6-12 hours
what is infected in HIV?
CD4 cells
how long does it take for HIV infection to be established?
three days
what is the target site for HIV?
CD4+ receptors
what cell types are CD4+ receptors found on?
t helper cells
dendritic cells
macrophages
microglial cells
what are HIV patients susceptible to?
viral, fungal and mycobacterial infections
infection induced cancers
what is a normal CD4 cell count?
500 - 1600
at what CD4 count is there the highest risk of opportunistic infection?
<200
what is the average time to death without treatment in HIV?
9-11 years
when does the onset of primary HIV infection occur?
2-4 weeks post infection
how does primary HIV infection present?
fever rash myalgia pharyngitis headache
what is risk of transmission like in primary HIV infection?
very high
massive viral load
what is an opportunistic infection?
an infection caused by a pathogen that does not normally produce disease in a healthy individual
what organism causes pneumocystis pneumonia?
pneumocystis jiroveci
what is the CD4 threshold for pneumocystis pneumonia?
<200
how does pneumocystis pneumonia present?
insidious onset
SOB
dry cough
what sign can be seen in pneumocystis pneumonia?
exercise oxygen desaturation
what can be seen on CXR in pneumocystis pneumonia?
interstitial infiltrates
reticulonodular markings
how is pneumocystis pneumonia diagnosed?
bronchoalveolar lavage (BAL)
immunofluorescence
PCR
how is pneumocystis pneumonia managed?
high dose co-trimoxazole +/- steroid
what is the prophylaxis given for pneumocystis pneumonia?
low dose co-trimoxazole
who is given prophylaxis for pneumocystis pneumonia?
everyone with CD4 count <200
what organism causes cerebral toxoplasmosis?
toxoplasma gondii
what is the CD4 threshold for cerebral toxoplasmosis?
<150
what does cerebral toxoplasmosis cause ?
formation of multiple cerebral abscesses
how does cerebral toxoplasmosis present?
headache fever focal neurological symptoms seizures reduced consciousness raised ICP
what is the CD4 threshold for cytomegalovirus?
<50
what does cytomegalovirus cause?
retinitis
colitis
oesophagitis
how does cytomegalovirus present?
reduced VA floaters abdominal pain diarrhoea PR bleeding
what type of screening should all individuals with CD4 <50 receive and why?
ophthalmic screening
complications of cytomegalovirus
what organism causes HIV associated neurocognitive impairment?
HIV 1
what causes increased incidence of HIV associated neurocognitive impairment?
reduced CD4 count
how does HIV associated neurocognitive impairment present?
reduced short term memory +/- motor dysfunction
what organism causes progressive multifocal leukoencephalopathy (PML)?
JC virus
what is the CD4 threshold for PML?
<100
how does PML present?
rapidly progressive
focal neurological symptoms
confusion
personality changes
what skin infections can be seen in HIV patients?
herpes zoster
herpes simplex
HPV
name three AIDS related cancers
kaposi’s sarcoma
non Hodgkin’s lymphoma
cervical cancer
what organism is associated with kaposi’s sarcoma in HIV?
human herpes virus 8
what is kaposi’s sarcoma?
a vascular tumour
how is kaposi’s sarcoma managed?
anti retrovirals
local therapies
systemic chemo
what organism is associated with non-hodgkin’s lymphoma in HIV patients?
EBV
what test should be offered to all patients with complicated HPV disease?
HIV testing
what are the three possible methods for transmission of HIV?
sexual
parenteral
mother to child
what is the most common mode for transmission of HIV?
sexual transmission
what factors can increase risk for sexual transmission of HIV?
anoreceptive sex
trauma
genital ulceration
concurrent STIs
what are three possible methods of parenteral transmission of HIV?
injecting drugs
infected blood products
iatrogenic
when can mother to child transmission of HIV occur?
in utero
delivery
breast feeding
what three markers can be used to detect HIV infection?
viral RNA
p24 antigen
HIV antibody
what is the first marker to become positive in HIV?
viral RNA
when is the p24 antigen positive in HIV?
around 6 weeks
when is the HIV antibody detectable in HIV?
can take three months
what do third generation HIV tests test for?
antibody
what do fourth generation HIV tests test for?
antibody and antigen
what is needed to perform a rapid HIV test?
finger prick blood specimen or saliva
how long does a rapid HIV test take?
20-30 mins
how long is the window period in which you can have HIV but have negative test?
45 days
this is for 4th generation tests
when should HIV treatment be started?
ASAP at all CD4 counts
what are the four groups of available anti-retroviral drugs?
reverse transcriptase inhibitors
integrase inhibitors
protease inhibitors
entry inhibitors
what are the two types of reverse transcriptase inhibitors?
nucleoside analogues
non nucleoside analogues
what does HAART stand for?
highly active anti-retroviral therapy
what is HAART?
a combination of three drugs from at least two drug classes to which the virus is susceptible
what are the four possible groups of anti-retroviral drugs?
reverse transcriptase inhibitors
integrase inhibitors
protease inhibitors
entry inhibitors
what are the two types of reverse transcriptase inhibitors?
nucleoside analogues
non nucleoside analogues
what does HAART stand for?
highly active anti-retroviral therapy
what is HAART?
a combination of 3 drugs from at least 2 classes to which HIV is susceptible
what does PrEP stand for?
pre exposure prophylaxis
who is given PrEP?
high risk individuals
what are the possible dosing schedules for PrEP?
daily or on demand
what drugs are given as PrEP?
tenofovir or emtricitabine
what is PEP?
post exposure prophylaxis
when should PEP be started?
within 72 hours of a high risk exposure
how long is PEP given for?
four weeks
what is given as PEP?
tenofovir/emtricitabine
raltegravir
what should be given to pregnant women with HIV?
HAART during pregnancy
how can a mother with HIV deliver if she has an undetectable viral load?
vaginally
how can a mother with HIV deliver if she has a detectable viral load?
c section
how long should neonates born to HIV positive mothers receive PEP?
two to four weeks
how can HIV positive mothers feed their babies?
exclusively formula feeding
