HIV/AIDS Flashcards
What is HIV?
A single stranded RNA retrovirus
How dos HIV infect humans?
Infects and replicates within the human immune system using host CD4 cells
What can HIV lead to without treatment?
Destruction of the immune system and AIDS
What was the prevalence of HIV in the UK in 2015?
~101,000
What % of the population of the UK had HIV in 2015?
0.16%
What % of people infected with HIV were unaware of their status?
13%
What % of people with HIV were men?
69%
What proportion of people with HIV are MSM?
Just under half
What cells does HIV replicate within?
CD4
What are CD4 cells also known as?
T helper cells
How does HIV infect a host CD4 cell?
Penetrates cell and empties the contents. The viral RNA is converted to DNA and combines with the host DNA
What enzyme causes HIV RNA to become DNA?
Reverse transcriptase
What enzyme integrates viral DNA into the host DNA in HIV?
Integrase
What happens when the CD4 cell divides in HIV?
Viral DNA is read and viral protein chains are created and push out of the cell retaining some cell membrane to form an immature virus
How does the immature HIV virus develop?
Viral protein chains are cut and assemble to create a working virus
What enzyme cuts the viral proteins in an immature HIV virus?
Protease
What happens to the host CD4 cell when HIV replicates?
It is destroyed
What is seroconversion in HIV?
The process pf producing anti-HIV antibodies during primary infection
What happens to the levels of CD4 cells during seroconversion?
Fall due to initial rapid replication of HIV
How dos HIV infect humans?
Infects and replicates within the human immune system using host CD4 cells
What can HIV lead to without treatment?
Destruction of the immune system and AIDS
How can the clinical features of HIV be divided?
Into stages of infection
What symptoms can be experienced during HIV seroconversion?
Flu-like symptoms
What happens to the levels of CD4 cells during seroconversion?
Fall due to initial rapid replication of HIV
How infectious is the patient during seroconversion?
Highly infectious
What can happen to HIV over the months-years following seroconversion?
Can enter a latent phase
What symptoms do many patients with HIV display after seroconversion?
None
What happens to CD4 levels after seroconversion?
Continue to fall
What happens to HIV viral load after seroconversion?
Increases
What happens to the patient as CD4 levels fall and viral load rises in HIV?
- Become more susceptible to infections
- Increasingly infectious
- Increasingly symptomatic
Over what period does HIV generally develop into AIDS?
10 years
How can HIV be transmitted?
- Unprotected sexual contact
- Sharing needles
- Medical procedures
- Vertical transmission
What types of sexual contact can spread HIV?
- Vaginal
- Anal
- Oral
What medical procedures can transmit HIV?
- Blood products
- Skin grafts
- Organ donation
- Artificial insemination
How can HIV be spread by vertical transmission?
- In-utero
- Childbirth
- Breast feeding
What factors can increase likelihood of contracting HIV when in contact with infectious components?
- Higher viral level
- Concurrent STI’s causing anogenital inflammation
- Breaks in the skin or mucosa
Is HIV preventable?
Yeah
What should practitioners be able to advise patients regarding HIV?
- Transmission reduction
- Safe sex
What are the risk factors for HIV?
- MSM
- IVDU
- High prevalence areas
- Unprotected sex with a partner who has lived or been to Africa
What are the stages of HIV infection?
- Seroconversion
- Asymptomatic infection
- Persistent generalised lymphadenopathy (PGL)
- Symptomatic HIV
- AIDS
How long after exposure do fourth generation HIV tests give reliable results?
4-6 weeks
What alternatives are available to fourth generation HIV testing?
- Rapid test kits
- Home sampling kits
What are the features of HIV seroconversion?
- Fever
- Muscle aches
- Malaise
- Lymphadenopathy
- Maculopapular rash
- Pharyngitis
What % of patients with HIV present at seroconversion stage?
20-60% (this is a massive range lol)
What is the viral load of HIV in asymptomatic infection stage?
Low - but continuing slow replication
Can HIV be cured?
No
How long can the asymptomatic infection stage of HIV last?
Many years
What is persistent generalised lymphadenopathy (PGL) in HIV?
Nodes >1cm in diameter at 2-extra inguinal sites for 3 months or longer (not due to any other cause)
What happens after the latent (asymptomatic) phase of HIV?
Becomes symptomatic
What symptoms may a patient have in symptomatic HIV infection?
- Weight loss
- High temperatures
- Diarrhoea
- Frequent minor opportunistic infections
What minor opportunistic infections can be present in the symptomatic phase of HIV?
- Candidiasis
- Herpes zoster
What is the symptomatic phase of HIV known as?
AIDS-related complex
What is AIDS-related complex regarded as?
An AIDS prodrome
What can happen to HIV infection if left untreated?
Can develop into AIDS
What happens in AIDS?
The immune system is significantly weakened and patient develops some defining illnesses
What are some AIDS-defining illnesses?
- Pneumocystis jiroveci pneumonia
- Non-hodgkin’s lymphoma
- TB
- Kaposi’s sarcoma
What are the first line investigations for HIV?
Fourth generation tests
What are fourth generation tests for HIV?
ELISAs that test for serum (or salivary) HIV antibodies and p24 antigen
How long after infection do fourth generation HIV tests give reliable results?
4-6 weeks
How long can rapid testing kits take to give a result on HIV infection?
30 minutes
What are the disadvantages to fourth generation HIV test alternatives?
- Less reliable
- Require confirmation by ELISA
What public health management is important when managing HIV?
Contact tracing
What treatment is given to manage HIV?
HAART (highly active anti-retroviral therapy)
What are the regular tests required to monitor HIV?
- CD4 count
- HIV viral load
- FBC
- U&E
- Urinalysis
- ALT, AST and bilirubin
What is the prognosis of HIV when using HAART?
Excellent
What is the risk of HIV transmission from a person complying fully with HAART?
Low risk
What can treatment of HIV with HAART reduce?
AIDS-related and non-AIDS-related mortality
What classes of drugs can be used to treat HIV?
- Nucleoside reverse transcriptase inhibitors (NRTIs)
- Protease inhibitors (PIs)
- Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
- Integrase strand transfer inhibitors (InSTIs)
How are are anti-HIV drugs used?
In combination
How do anti-HIV drugs reduce viral load?
Target enzymes involved in replication and maturation of HIV
How are anti-HIV drugs combined?
Often into a once-daily single tablet
What are some examples of single tablet HIV treatments?
- Atripla
- Stribild
- Eviplera
- Ttriumeq
What is Atriplas?
Tenofovir + emtricitabine + efavirenz
What is Stribild?
Elvitegravir + cobicistat + tenofovir + emtrictabine
What is Eviplera?
Tenofovir + emtricitabine + reilpivirine
What is Triumeq?
Abacavir + lamivudine + dolutegravir
What is key to successful management of HIV?
Good compliance for the rest of their lives
What can non-adherence to HARRT result in?
Resistance mutations making treatment difficult or impossible
What other factors must be considered when managing HIV?
Psychological impact of living with or being diagnosed with HIV
What additional tests may HIV patients require in the future?
- Pregnancy testing
- Resistance testing
What can people who believe they have been exposed to HIV be treated with?
Post-exposure prophylaxis (PEP)
Within what period from HIV exposure can someone commence PEP?
72 hours
What is the aim of PEP for HIV?
Reduce the risk of being infected
How long does a HIV PEP course last?
1 month
What is a HIV PEP regime?
Truvada OD + Raltegravir BD
How can HIV be transmitted vertically?
- In-utero
- Delivery
- Breast feeding
How can vertical transmission of HIV be reduced?
- Antenatal antiretroviral therapy during pregnancy and delivery
- Avoidance of breastfeeding
- Neonatal post-exposure preophylaxis
What do the collective interventions reduce the risk of HIV vertical transmission to?
<1%
What is the risk of vertical transmission of HIV with no interventions?
1 in 4
Are caesarean section births indicated in HIV?
Not if the viral load is undetectable at delivery
