8.2 HIV Flashcards
What does HIV stand for and what are the 2 types?
Human Immunodeficiency Virus
HIV-1 and HIV-2
What type of virus is HIV and what family does it belong to?
HIV is a retrovirus and belongs to the lentivirus family
What are the 4 main bodily fluids are associated with HIV transmission
1) vaginal and seminal fluids
2) rectal fluid
3) breast milk
4) blood
What are the chances of an HIV positive mother passing on HIV to her child in the UK, if she has received appropriate medical intervention?
Less than 1%
List 5 other factors that increase transmission of HIV
1) A high plasma HIV viral load in the source
2) Breaches in the mucosal barrier (eg. mouth/genital ulcers, trauma following sexual assault or first intercourse, menstruation)
3) STIs enhance transmission and increase HIV shedding from the genital tract.
4) greater if ejaculation occurs
5) Non-circumcision
What does PEP stand for and what is it?
“post-exposure prophylaxis”
PEP is when you are given HIV treatment if you have been exposed/at risk of HIV
It is a 28 day therapy reduces risk of aquiring HIV from incidence
Give an example of when post-exposure prophylaxis (PEP) be recommended?
You have experienced a needle stick injury when taking blood from a person with HIV (or of unknown HIV status)
What does HIV cause and what does this make you more susceptible too?
Progressive damage to the immune system
leads to severe immunodeficency, opprtuntistic infections and death
What is the primary immune dysfunction caused by HIV?
What is the process of HIV infection (4)
Depletion and impaired function of the T helper lymphocytes
1) HIV gains access to cells via CD4 receptor and enters
2) reverse transcriptase makes a DNA copy of the RNA genome and integrates it into host DNA
3) complete virus particles are formed during replication
4) these are released from the infected cells leading to a rapidly reproducing virus
What is the mechanism of impaired function to T-helper cells?
Mechanism is uncertain but probably includes:
- enhanced apoptosis
- inhibition of CD4 lymphocyte growth
What could be measured as a marker of immune function is suspected or infected HIV patients?
Peripheral CD4 cell count
What are the 3 main clinical phases of HIV (3A’s)
1) Acute seroconversion – occurs within a few weeks of initial infection. Marks the period of time when HIV antibodies develop and are detectable. People are extremely infectious at this stage.
2) Asymptomatic – can last years to decades. People can be asymptomatic or have few symptoms. If left untreated, there is steady decline in CD4 T cells.
3) Acquired immunodeficiency syndrome (AIDS) – final stage of HIV infection but does not develop in everyone. Caused by extremely low CD4 count and damage to immune system
Following the period of clinical latency during HIV infection what symptoms may develop and how can these progress?
Iinitially, constitutional symptoms (tiredness, weight loss, fatigue), which can progress to opportunistic, potentially fatal, infections
What is meant by Seroconversion following early Infection of HIV?
What would be seen during this period and what can be said about the “set point” reached?
Serocoversion is the period when the body starts producing detectable levels of HIV antibodies. It is a partial immune response by the body in attempt to fight infection.
During this stage we get a rise in CD4 and a fall of viral load until a set point. The point reached varies from person-person:
If the set point is a high viral load ➞ person is more likely to have a rapid CD4 rate of decline after
If the setpoint is a low viral load ➞ person is more likely to have a slow CD4 rate of decline after
Around how many people experience symptoms shortly after HIV infection and what is this process called?
List 4 possible symptoms of an acute HIV infection
The majority of people (70% to 90%) will experience symptoms shortly after HIV infection during serocoversion
Symptoms include flu-like symptoms:
- sore throat
- fever
- malaise
- myalgia
What is required to be diagnosed with AIDs
Either the presence of:
1) CD4 T cell count is <200 cell/mm3.
2) presence of AIDs defining conditions (opportunistic infections directly associated with advanced HIV infection)
Give an example of 4 Aids-defining conditions
1) Cytomegalovirus retinitis (CMV retinitis)
2) Mycobacterium Tuberculosis
3) Candidiasis
4) Pneumocystitis Jiroveci
What are the 4 main routes HIV spread through?
1) sexual ➞ unprotected sex with an HIV+ individual (anal sex = highest risk)
2) injecting drug use
3) vertical transmission ➞ mother to child during intrauterine life, delivery, breast feeding
4) blood products ➞ transfusions or organ/tissue transplants (rare due to testing)
What is ART and explain simply what it does
What is HAART?
Antiretroviral Treatment- aims to suppress the virus and may help to reverse some damage to the immune system. Acts by halting viral replication at various places throughout the HIV life cycle
HART: Highly active antiretroviral therapy
What is the main challenge in the treatment of HIV
HIV is continually changing and often becoming resistant to the medications
What are the 3 main drugs used in the treatment of HIV
What is the “basic recipe”
1) nucleoside reverse transcriptase inhibitors (NRTIs)
2) protease inhibitors
3) Integrase inhibitors
Basic recipe = two NRTIs + one drug from a different class
Give 3 benefits of ART to the individual and 3 benefits to the population
Individual
1) improved life expectancy
2) decreased morbidity
3) decreased risk to partners
Population
1) decreased health care costs (less people hospitalised)
2) Productivity
3) decreased Transmission
List 2 impacts of HIV being undiagnosed on the following:
Individual
Society
Individual: late presentation, illness ➞ death
Society: transmission and cost of advanced disease
Testing is KEY!!! (HIV is detectable after 4 weeks)
List 4 conditions/symptoms that indicate HIV testing may be required
1) Unexplained weight loss
2) Chronic diarrhoea
3) Pneumonia
4) Lymphadenopathy
List 4 methods to prevent transmission of HIV
1) Condom use
2) Expanded HIV testing
3) Prompt ART
4) Use of PrEP (pre-expose prophylaxis, pill taken to prevent HIV)
What defines clinical presentation of HIV and how is it monitored?
What defines disease progression of HIV and how is it monitored?
Clinical presentation is related to degree of immune suppression ➞ monitored by measuring CD4 count.
Disease progression is related to viral load (higher load = faster progression) ➞ monitored by measuring HIV RNA
What is Aspergillosis? What is it caused by?
Aspergillosis is any illness caused by fungus when it colonizes a host
Caused by Aspergillus (genus made up of several species of molds that have the potential to cause serious fungal illnesses in humans and animals)
Where is Aspergillus commonly found?
What part of the body does it commonly affect?
parasite is commonly found in compost bins, grain, construction materials and dust
The fungus releases spores, which, when breathed in can cause respiratory disease
Inhalation of Aspergillus does not normally cause problems. List 3 instances where inhalation could be serious or fatal
1) inhalation of large numbers of spores
2) chronic lung disease
3) immunocompromised
How is Aspergillosis diagnosed and treated?
Diagnosis is usually made on the basis of case history and symptoms (can use X- rays, fungal growth & biopsies)
Treatment = Voriconazole (anti-fungal)
resistant strains = any number of common antifungals
