10. HIV Flashcards
what are the common symptoms of HIV that usually only occur in HIV?
Oral candidiasis
Kaposi’s sarcoma
Pneumocystis pneumonia (PCP)
What is HIV?
Human immunodeficiency virus
Describe HIV
Retrovirus - ssRNA -> DNA -> ssRNA
Infects cells with CD4 surface receptor
HIV replicates inside cells, destroys cell, causes inflammation and spreads to/infects more cells
Does HIV work?
- Free virus
- Binding and fusion - virus binds to CD4 molecule and one of 2 coreceptors (CCR5 or CXCR4), common on cell surface then virus fuses with cell
- Infection - virus penetrates cell, contents emptied into cell
- Reverse transcription - single strands of viral RNA are converted into double stranded DNA by reverse transcriptase enzyme
- Integration - viral DNA is combined with cell’s own DNA by integrate enzyme
- Transcription - when infected cell divides, viral DNA is read and long chains of proteins are made
- Assembly - sets of viral protein chains come together
- Budding - immature virus pushes out of cell, taking some cell membrane with it
- Immature virus breaks free of infected cell
- Maturation - protein chains in new viral particle cut by protease enzyme into individual proteins that combine to make a working virus
How is HIV transmitted?
Contact of infected bodily fluids with mucosal tissue/blood/broken skin
From sex, blood transfusion, contaminated needles, perinatal transmission
What are the 4 stages of HIV?
Primary infection/sercoconversion
Latent infection
Symptomatic infection
Severe infection/AIDS
What are the main symptoms of acute HIV infection?
Fever, weight loss, mouth sores or thrush, myalgia, liver and spleen enlargement, nausea, vomiting, rash, lymphadenopathy, headache, neuropathy
What are some conditions associated with severe HIV?
Cryptococcal meningitis Toxoplasmosis Cold sores and ulcers Oral candidiasis Hyperglycaemia Histoplasmosis PCP TB Osteoporosis Heart disease HCV HPV PID HIV wasting syndrome
What are the factors affecting HIV transmission?
Type of exposure - type of sexual act, transfusion vs needle stick vs mucous membrane
Viral level in blood - transmission unlikely if undetectable VL
Condom use
Breaks in skin or mucosa - other STI, sexual assault
What can help a patient live to the average HIV life expectancy of 78?
Early detection
Treatment
Adherence
Healthy living - smoking, alcohol, metabolic problems
What are the 2 diagnostic blood tests that can be done for HIV?
Serology - HIV antigen, HIV antibody, +ve in 4 weeks, result on same day, may get false negative result
PCR - detects HIV nucleic acid, detects very early infection, expensive, results slow, used for follow up
What is the rapid tests for HIV?
Low cost, <1 hr Detect HIV antibody Blood test (finger-prick) Oral Home testing kits Postal testing If negative - accurate May get false positive result
What strategies would you use to reduce prevalence of HIV?
Anti-retro viral drugs (ARVs)
What are the aims of HIV treatment?
Undetectable HIV viral load Reconstitute CD4 count/immune system Reduce general inflammation Reduce risk of transmission Good quality of life Normalise lifespan
When should treatment be started?
ASAP, regardless of CD4
