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
