Lecture 6 - HIV (Blood Borne Diseases) Flashcards
If HIV goes untreated what usually occurs?
AIDS Develops leading to death
If Hep B and Hep C go untreated what usually develops?
Liver Cirrhosis
What unusual infections tend to develop as a result of untreated HIV?
Oral candidiasis
Kaposi’s sarcoma
PCP (Pneumocystis pneumonia)
What is Oral candidiasis?
What are its signs?
Its oral thrush
Causes white spots/patches on tongue, cheeks, gums and throat
What is Kaposis sarcoma?
Type of cancer caused by Human Herpes Virus 8
Cancer grows in skin or mucous membranes of GI tract
Red/purple lesions on skin form
What is PCP?
A serious fungal infection of the lungs causing pneumonia (fluid build up in the lungs)
Caused by Pneumocysitis jirovecii
What type of infections are common in patients with HIV/AIDS?
Reactivated viruses
Yeast infections
Mould infections
Protozoan infections
What is the outcome of HIV infection?
NO CURE
Chronic infection but Treatment in place to hopefully avoid disability
DEATH IF UNTREATED
What type of virus is HIV?
Retrovirus
HIV is a retro virus:
What does this mean in terms of its genetic information?
It has Single stranded RNA
What cells does the HIV virus target?
Cells with CD4 receptor
(Normally T cells)
Which cells in the body have the CD4 receptor?
IMMUNE CELLS
T-helper lymphocytes
Macrophages
Monocytes
What enzyme does HIV use once its invaded a cell with a CD4 receptor?
Reverse transcriptase
What is the function of reverse transcriptase?
Convert the single stranded RNA into double stranded DNA
How does HIV cause damage to CD4 cells and therefore the body?
Binds to CD4 receptor on cell
Invades cell
Its RNA is converted to DNA by reverse transcriptase
The viral DNA combines with cells DNA
Chains of viral proteins now produced by cell
Viral proteins leave cell taking membrane with t
Virus goes on to infect more cells
REDUCES NUMBER OF IMMUNE CELLS IN THE BODY
How is HIV transmitted?
Contact of infected bodily fluids itch mucosal tissue/broken skin/blood:
-Sexual contact
-Blood transfusion
-Contaminated needless
-Perinatal transmission
How can perinatal transmission occur?
Cross from placenta to child
During delivery via infected birth canal
Infected breast milk
What are the 4 stages of HIV infection?
Primary infection
Latent infection
Symptomatic infection
Severe infection/AIDS
What happens to viral load and CD4 cell count in primary infection?
CD4 count drops as viral load rapidly increases
Once immune system starts destroying HIV, CD4 count recovers and Viral load drops
What happens in the latent infection stage?
Remaining HIV begins slowly destroying CD4 cells causing their levels to slowly fall
Viral load now begins to slowly increase
What happens in the symptomatic infection stage?
CD4 cell levels are rapidly dropping due to more and more HIV viruses destroying them
First opportunistic infection occurs at this stage or recurrent infections begin
What happens in the severe infection/AIDS stage?
CD4 cell levels extremely low
What are the symptoms of Acute HIV infection?
Very non specific symptoms so:
If someone has flu like symptoms and a possible exposure to HIV think HIV
What happens to the bodies vulnerability to infections as CD4 cell levels drop?
Increases and severity of infections increases
What tends to happen when CD4 cell count drops below 200cells/microlitre?
Severe infections
AIDs defining symptoms and cancers linked with HIV/AIDs
What factors affect HIV transmission?
Type of exposure (Type of sexual act, needlestick or mucous membrane?)
Viral load (Higher = more likely infection)
Condom usage
Any breaks in skin or mucosa
What is the 90:90:90 HIV target?
90% of all people should be aware of their HIV status
90% of all positive individuals should be on treatment (antiretrovirals)
90% of these people on treatment should have an undetectable viral load
If HIV is detected early is life expectancy dramatically affected?
No as long as CD4 cell count is preserved enough and patient adheres to treatment
What are the 3 types of HIV tests?
Serology
PCR
Rapid tests
What is tested for in serology test for HIV?
Antigens (HIV proteins)
Antibodies (made by body in response to virus)
Normally HIV antigens since body takes a while to begin producing antibodies against the virus
What is tested for in PCR for HIV?
Detects viral nucleic acid
What is tested for in rapid testing for HIV?
Detect HIV antibody
What is the advantages of serology testing for HIV?
And disadvantage?
Can detect positive 4 weeks after infection
Results on same day
May get false negative
What are the advantages of PCR HIV testing?
Highly sensitive
Detects infection after a few days
What are the disadvantages of PCR HIV testing?
Expensive
Slow
What are the advantages of Rapid tests for HIV?
1 disadvantage
Very fast
If negative = accurate
May get false positive
Who should be tested for HIV?
Everyone of the rate exceeds 2 in 1000 in a population
Also if people have certain other infections
What can different types of Anti-Retroviral drugs do?
Prevent viral entry in CD4 cell
Inhibit reverse transcriptase
Inhibit enzyme (Integrase) that integrates the transcripted viral DNA into the cell
Why are multiple ARVs usually given to a patient?
The virus rapidly develops resistance so multiple drugs makes it harder for the virus to survive
What are the strategies for treating and reducing HIV prevalence?
Increase condom use
ARV
Widespread testing and screening
Test all pregnant women
Post expose prophylaxis and Pre exposure prophylaxis
What are some ethical dilemmas with HIV?
Stigma
Harming unborn baby
Patient confidentiality vs:
-Health of
Mother
Unborn child
Sexual contacts
Older child
Risks to patients and staff
