HIV and AIDS Flashcards
spread of HIV
sexual transmission injection drug misuse blood products vertical transmission (mother to child) organ transplant
think of high risk and unknown risk
HIV testing
pts should be counselled before being tested for HIV
unconscious pts can be tested if you think it’s in the pts interest to have the test
HIV immunology
infects and destroys T helper cells that are CD4 +ve (CD4 receptor on their surface)
CD4 receptors aren’t exclusive to lymphocytes - also present on the surface of macrophages and monocytes, cells in the brain, skin and many other sites
natural history of HIV and CD4 count
over course of infection: CD4 count declines and HIV viral load increases
increasing risk of developing infections and tumours
severity of these illnesses is greater the lower the CD4 count
normal CD4 count
> 500
CD4 count for AIDS diagnosis
CD4 count <200
HIV infection classification
original - clinical i.e. certain infections/tumours/pneumonia that you had associated with profound immune suppression, this was considerable help in estimating the incidence of disease in the developing world where HIV testing was less readily available
pragmatic approach is to consider symptomatic vs asymptomatic disease
how many clinical stages of HIV are there
4
clinical stage I HIV
asymptomatic
persistent generalised lymphadenopathy (PGL)
performance scale 1 - asymptomatic, normal activity
clinical stage II HIV
weight loss <10% TBW
minor mucocutaneous manifestations (seborrheic dermatitis, prurigo, fungal nail infections, recurrent oral ulcerations, angular chelitis)
herpes zoster, within the last 5yrs
recurrent URTI i.e. bacterial sinusitis
+/or performance scale 2: symptomatic, normal activity
clinical stage III HIV
weight loss >10% TBW
unexplained chronic diarrhoea >1mth
unexplained prolonged fever (intermittent or constant) >1mth
oral candidiasis
oral hairy leukoplakia
pulmonary TB within past yr
severe bacterial infections
+/or performance scale 3: bedridden <50% of day during last mth
clinical stage IV HIV
HIV wasting syndrome:
pneumocystic carinii pneumonia
toxoplasmosis of the brain
cryptosporidiosis w/ diarrhoea >1mth
cryptococcosis, extrapulmonary
cytomegalovirus - disease of an organ other than liver, spleen or lymph nodes
HSV infection - mucocutaneous >1mth or any duration visceral
progressive multifocal leukoencephalopathy (PML)
any disseminated endemic mycosis
candidiasis - oesophagus, trachea, bronchi or lungs
atypical disseminated mycobacteriosis
non-typhoid salmonella septicaemia
extrapulmonary TB - lymphoma
kaposi’s sarcoma (KS)
HIV encephalopathy
+/or performance scale 4: bedridden >50% of the day during last month
HIV vs AIDS
certain infections and tumours that develop due to immune weakness are classified as AIDS illness
if you have no symptoms then you have asymptomatic HIV infection only
virtually everyone w/ an AIDS illness should recover from it and then be put on antivirals to keep them free from any future illnesses
natural hx from HIV to death
acute infection - seroconversion asymptomatic HIV related illnesses AIDS defining illness death
1y HIV/seroconversion
~30-60% of pts have a seroconversion illness (HIV antibodies first develop)
abrupt onset 2-4wks post-exposure, self limiting 1-2wks
symptoms generally non-specific and differential diagnosis includes a range of common conditions
symptoms of 1y HIV/seroconversion
flu-like illness fever malaise and lethargy pharyngitis lymphadenopathy toxic exanthema
lasts much longer than normal viral illness
looks like glandular fever but EBV serology not in keeping
treatment of HIV - when to start
asap unless very strong objection to treatment
antiviral treatments
AZT - only used now for very specific indications DDI DDC - combination therapy is key 3TC D4T
antiretroviral therapy
different classes of drugs acting on different stages in HIV lifecycle
combination antiretroviral therapy (cART) means 2/3 drugs from at least 2 groups
adherence needs to be good
cART can lead to a normal life but side effects and drug interactions can be an issue for some pts
where do antiretrovirals acts
reverse transcriptase inhibitors - inhibit viral RNA transcription into DNA
integrase inhibitor - prevent viral DNA being integrated into host genome
protease inhibitor - prevent maturation of the virus
when and what drugs to start
start all pts at diagnosis regardless of CD4
any pregnant women - start before 3rd trimester
after starting combination treatment consider adjustment if VL not adequately suppressed after 4-6wks of therapy
when to delay HIV treatment
only delay starting if concerned about an immune reconstitution illness e.g. cryptococcal meningitis
ideally start once baseline genotypic resistance known
current life expectancy
related to lowest CD4 before starting therapy in pts diagnosed 20y/o
<100 - 52
100-200 - 62
>200 - 70+
length of treatment
treatment once started is lifelong
treatment may be altered but pts will always need to be taking some form of antiviral medication
treatment of HIV is similar to that of a chronic condition rather than an infection
why does HIV treatment fail
poor adherence leads to viral mutation and resistance
incomplete suppression - inadequate potency, inadequate drug levels, inadequate adherence, pre-existing resistance
selection of resistant quasispecies
types of antiviral drugs
nucleoside reverse transcriptase inhibitors
non-nucleoside reverse transcriptase inhibitors
protease inhibitors
integrase inhibitors
nucleoside reverse transcriptase inhibitors side effects
marrow toxicity
neuropathy
LIPODYSTROPHY
non-nucleoside reverse transcriptase inhibitors side effects
skin rashes
hypersensitivity
drug interactions
neuropsychiatric side effects
protease inhibitors side effects
drug interactions
diarrhoea
LIPODYSTROPHY
hyperlipidaemia
integrase inhibitors side effects
rashes
headaches
neuropsychiatric side effects
lipodystrophy - what to do
change drugs - less likely with newer agents
cosmetic procedures - facelift, liposuction, fillers
challenges of HIV care
age related changes occur earlier than normal
osteoporosis cognitive impairment malignancy cerebrovascular disease renal disease ischaemic heart disease DM
HIV prevention
behaviour change and condoms
circumcision
TREATMENT AS PREVENTION - VL undetectable = untransmissable
pre-exposure prophylaxis (PrEP)
post-exposure prophylaxis for sexual exposure (PEPSE)
