HIV Flashcards
(42 cards)
1
Q
What is the difference between HIV / AIDS?
A
HIV:
- having contracted the human immunodeficiency virus
AIDS:
- HIV progresses and the person becomes immunodeficient
- they are susceptible to opportunistic infections
- now referred to as late-stage HIV
(acquired immunodeficiency syndrome)
2
Q
What is HIV and how does it cause illness?
A
- it is a RNA retrovirus
- the virus enters and destroys CD4 T-helper cells of the immune system
- reverse transcriptase integrates HIV DNA into host DNA, which takes 3-5 days after exposure
- HIV virions budding out will destroy the host T cell
3
Q
How does HIV typically present?
A
- there is an initial seroconversion flu-like illness within a few weeks of infection (primary HIV)
- the person is then asymptomatic until the condition progresses to immunodeficiency
- immunodeficient patients develop AIDS-defining illnesses** + **opportunistic infections
- this progression can take several years
4
Q
Why does it take several years for HIV to progress to immunodeficiency?
A
- the CD4 cells are destroyed faster than they are being made
- it takes time for the CD4 count to become so low that immunodeficiency results
5
Q
How can HIV be transmitted?
A
- unprotected anal, vaginal or oral sexual activity
- mother to child at any stage of pregnancy, birth or breastfeeding (vertical transmission)
- mucous membrane, blood or open wound exposure to infected blood or bodily fluids
- e.g. sharing needles, blood splashed in an eye
6
Q
What type of sex is associated with an increased risk of HIV transmission?
A
- receptive anal intercourse is the highest risk, followed by:
- receptive vaginal intercourse
- insertive anal intercourse
- insertive vaginal intercourse (lowest risk)
7
Q
What other sexual factors can increase the risk of HIV transmission?
A
- trauma (e.g. sexual assault / fisting) that damages the skin
- presence of other STIs / genital infections
- e.g. HSV, gonorrhoea, syphilis, BV
8
Q
What is the risk of contracting HIV from oral sex?
A
- the likelihood of transmission is rare, but it is possible
- the person who is receiving is at greater risk
- dental treatment / bleeding gums / ulcerative conditions increase the risk
!! HIV cannot be transmitted through saliva !!
(i.e. kissing / sharing cups)
9
Q
What is involved in the natural history of HIV?
A
- there is a sharp drop in CD4 count shortly after primary infection
- opportunistic infections may arise at this point
- CD4 count then comes back up and stays steady for some time
- it then gradually declines as HIV viral load increases
- this is when symptoms start to develop
10
Q
What are the typical symptoms of primary HIV infection (seroconversion)?
A
- symptoms begin 2-6 weeks** after infection and last for **5-10 days
- fever
- pharyngitis
- lymphadenopathy
- skin rash
- myalgia
- headache / malaise
- N&V
!! a recent negative HIV test supports the diagnosis !!
11
Q
Why would a HIV test be negative during primary infection?
A
- it can take up to 3 months for antibodies against HIV to be made
- p24 antigen may be positive at this stage, but antibodies will be negative
12
Q
How can someone tell they are in the asymptomatic stage of HIV infection?
Why is it important to detect this?
A
- the only way to tell is by doing a blood test for HIV
- there is ongoing viral replication causing immune system damage during this stage
- this chronic inflammatory state increases the risk of malignancy + cardiovascular disease
13
Q
What symptoms may develop when someone enters the symptomatic stage of HIV infection?
A
skin lesions:
- folliculitis
- multi-site herpes zoster
- seborrhoeic dermatitis
oral lesions:
- candidiasis
- oral hairy leukopenia
recurrent bacterial infections:
- pneumonia
- impetigo
abnormal blood results:
- lymphopenia
- thrombocytopenia
non-specific symptoms:
- diarrhoea
- fever
- myalgia
- persistent lymphadenopathy
14
Q
When do AIDS-defining illnesses occur?
A
- these are associated with end-stage HIV infection
- the CD4 count has become so low that opportunistic infections / malignancies can occur
15
Q
Why are there worse outcomes associated with diagnosis at a late stage?
A
- the lower the CD4 count, the greater the damage to the immune system
- there is less chance of immune system recovery
16
Q
What are examples of AIDS-defining illnesses?
A
- Kaposi’s sarcoma
- pneumocystis jirovecii pneumonia
- cytomegalovirus infection
- candidiasis (oesophageal / bronchial)
- lymphomas
- tuberculosis
17
Q
What is the drawback of HIV testing using HIV antibodies?
A
- it can take up to 3 months to develop antibodies to the virus
- HIV antibody tests can be negative for 3 months following exposure
- a repeat test is required within 3 months if the initial test is negative
18
Q
What test can detect HIV earlier than the antibody test?
A
testing for the p24 antigen:
- this is a antigen specific to HIV
- it can given a positive result earlier in infection than the antibody blood test
19
Q
What 2 tests are used in the monitoring of HIV?
A
- CD4 count
- viral load (VL)
20
Q
What is the CD4 count and why is it monitored?
A
- the number of CD4 cells in the blood
- this is an indicator of the risk of opportunistic infections
- CD4 count usually improves with treatment
21
Q
What is a normal CD4 count?
When is someone at greater risk of opportunistic infections?
A
normal range:
- 500 - 1,200 cells / mm3
- there is no need to monitor regularly if > 350 cells / mm3
end-stage HIV:
- < 200 cells / mm3
- the patient is at a high risk of opportunistic infections
22
Q
What does viral load measure?
A
- it is the number of copies of HIV RNA per ml of blood
- it is monitored to assess disease progression +/- treatment response
23
Q
What is a normal viral load?
A
- “undetectable” refers to a viral load below the detectable range
- this is usually 50 - 100 copies / ml
- the aim of treatment is to get viral load < 50 copies / ml
24
Q
What is the typical treatment regime for HIV?
A
- highly active antiretroviral therapy (HAART / ART) is used
- this is usually 3 different drugs in combination
- treatment is lifelong
- compliance is essential as viral replication under partial pressure can result in drug resistance
25
What is the aim of HIV treatment?
to achieve a **normal CD4 count** and **undetectable viral load**
26
What additional prophylaxis is given to patients with a CD4 count \< 200?
prophylactic **_co-trimoxazole_**
* this is to protect against **pneumocystis jirovecii pneumonia**
27
What is significant about HIV and cardiovascular risk?
* HIV **increases the risk** of developing cardiovascular disease
* close monitoring of **_blood lipids / risk factors_** is required
* **_statins_** may be started to reduce CVD risk
28
How is cervical screening different for patients with HIV?
* they are offered **_yearly_ smear tests**
* HIV predisposes to **_HPV infection_** and **cervical cancer**
29
What is important about vaccinations in a HIV positive patient?
**_ALL vaccinations_** should be up to date:
1. influenza
2. pneumococcal
3. hepatitis A + B
4. tetanus
5. diphtheria
6. polio
***!! patients should AVOID live vaccines !!***
30
What advice is given around sexual intercourse and HIV?
* condoms are advised for all acts of sexual intercourse
* **transmission is almost unheard of** when the **viral load is undetectable**, but still possible
* partners should have **regular HIV tests**
* **_unprotected sex / pregnancy**_ are considered when _**viral load is undetectable_**
31
When is a normal vaginal delivery recommended?
for all women with a **viral load \< 50 copies / ml**
32
When is Caesarean section recommended?
What medication may be given during the procedure?
* considered when viral load **\> 50 copies / ml**
* highly recommended when viral load **\> 400 copies / ml**
* **_IV zidovudine_** is given if viral load is **unknown** or there are **\> 10,000 copies per ml**
33
What prophylactic treatment is given to low-risk babies?
* when mother's viral load **\< 50 copies / ml**
* **_zidovudine**_ is given for _**4 weeks_**
34
What prophylactic treatment is given to high risk babies?
* when mother's viral load **\> 50 copies per ml**
* **_zidovudine, lamivudine + nevirapine_** are given for 4 weeks
35
What is the recommendation for breastfeeding?
* HIV **can be transmitted during breastfeeding**, even when the **viral load is undetectable**
***!! breast feeding is not recommended !!***
* it is sometimes attempted with close monitoring if mother is very keen and viral load is undetectable
36
What is the rapid point of care test for HIV?
* self administered blood test with an immediate result
* if the test is positive, a blood test is required for confirmation
37
When sending a venous blood sample to the lab to test for HIV, what must always be done as follow-up?
* a **second confirmatory sample** should be sent to ensure no labelling / lab process error
* **action is taken based on first result**
38
What are the guidelines around telling other people following a new HIV diagnosis?
* **encourage the patient to tell their contacts** (but this cannot be enforced)
* **anonymous provider referral** is available
* failure to disclose can result in criminal proceedings if the transmission was preventable
39
What is pre-exposure prophylaxis (PrEP) and who may used this?
* taken by **_HIV-negative_** people **before, during and after sex**
* **2 tablets** are taken **2-24 hours before** sexual activity
* it can be taken daily or around sexual activities
* it **_prevents HIV contraction_** but does not protect against other STIs
* regular testing is required
40
What is post-exposure prophylaxis (PEP)?
When is it taken?
* HIV medications that are taken **_after high risk sex / exposure_**
* medication taken for **28 days**
* should be started as soon as possible, but can be taken **_up to 72 hours_** after exposure
41
What is the current PEP regime?
* Truvada (emtricitabine + tenofovir)
AND
* raltegavir
taken for 28 days
42
When must HIV tests be performed in someone taking PEP?
* perform a HIV test **immediately** and **after 3 months** to confirm a negative status
* individuals should **abstain from sexual activity** for 3 months
