HIV Flashcards
definition of HIV
the prescence of antibiodies against the virus
-chronic viral infection
definition of AIDS
CD4 count of <200
AIDS assoc. illnesses
- candidiasis (not in mouth)
- cervical cancer
- cmv
- encephalopathy
- herpes simplex
- isoporiasis
- karposi sarcoma
- lymphoma
- p.jiroveci
- leukoencephalopathy
- salmonella
- toxoplasmosis of the brain
- wasting syndrome
transmission hiv
- sexual: anal higher risk than vaginal
- IVDU
- transfusion/ blood products
- mother to child 25%
2 types of HIV
type 1-worldwide
type 2-western africa
dx of hiv
- point of care test=antibodies to HIV serology
- PCR can do viral load
biological features of hiv
- Hypervariability especially envelope
- Error-prone replication
- High level kinetics of replication (lots of viruses)
- Rapid evolution of mutants
- Integration into host dna-latency within cells
- Infects long lived cells (eg macrophages) as well as short lived lymphocytes
boundaries of high,med and low viral load
high >100,000
medium 10,000-100,000
low <10,000
monitoring hiv
- viral load
- cd4 count
- antibodies
what brings the initial viremia of hiv under control
the hiv specific immune response which leads to a decrease in virus concentration
what type of virus is hiv
rna retrovirus so has reverse transcriptase to make dna
clinical presentationof primary infection of AIDS and seroconversion
-incubation period 2-4 weeks
-50% asymptomatic
-fever, headache
-lymphadenopathy, rash-maculopapula, roseola rash like
pharyngitis
-neuro involvement eg meningoencephalitis
seroconversion=when develop antibodies
how long till blood tests are positive
positive within 3-4 weeks
non-specific symptoms of hiv
-weight loss
-fever
-malaise
-mild immunodeficiency
-shingles and candidia, recurrent hsv, hairy oral leucoplakia, molluscum contagiosum
-parotid enlargement
-immunodysregulation
so immune thrombocytopaenia, drug allergies, s
-sebhorrheic dermatitis
what type of TB is more common in europe
extra pulmonary or non-cavitiating rather than cavitiating
% of patients with aids with tb at post-mortem
50%
lymphoma assoc. to aids
-non hodgkin large b cell immunoblastic and cerebral lymphoma
cancer assoc. to aids
kaposi sarcoma
resp illness assoc. to aids
recurrent pneum
pneum jiroveci
neuro illness asssoc. to hiv
hiv encephalopathy cmv, hsv encephalitis Progressive multifocal leukoencephalopathy - Toxoplasma encephalitis - Cryptococcal or tb meningitis - Peripheral neuropathy
gi illness assoc. to hiv
GI illness
- Diarrhoea, weight loss and colitis
- RUQ pain, abnormal LFTs, cholangiopathy
hiv treatment
antiretroviral drugs triple therapy eg zidovudine
targets for hiv therapy
- entry inhibitors
- reverse transcriptase
- integrase
- protease
serology hiv
- HIV serology is 100% sensitive and specific
- Persists in all those who have been infected- positive serology=active infection
- Spontaneous resolution doesn’t occur
- Clinical disease will occur eventually in >95% of infected persons
hiv testing
to establish informed consent for HIV testing. Lengthy pre-test HIV counselling is not a requirement, unless a patient requests or needs this.
The essential elements that the pre-test discussion should cover are:
• the benefits of testing to the individual
• details of how the result will be given.
