HIV Flashcards
What is HIV?
Human immunodeficiency virus
How is HIV spread?
- Sexual transmission - Injection drug misuse - Blood products - Vertical transmission - Organ transplant
Can we test unconscious patients for HIV?
Unconscious patients can be tested if you think it is in the patient’s interest to have the test (Having had a negative HIV test does not affect insurance premiums)
How does HIV infection affect the immune system?
- HIV infects and destroys cells of the immune system especially the T-Helper cells that are CD4+ (have a CD4 receptor on their surface) - CD4 receptors are not exclusive to lymphocytes – they are also present on the surface of macrophages and monocytes, cells in the brain, skin, and probably many other sites.
What is the natural history of the HIV infection?
CD4 count declines & HIV viral load increases (severity of these illnesses is greater the lower the CD4 count (normal CD4 > 500))
What are the features of Clinical stage 1?
Asymptomatic Persistent generalised lymphadenopathy
What are the features of clinical stage 2?
Weight loss <10% Herpes zoster, within last 5 years
What are the features of clinical stage 3?
Weight loss >10% Unexplained chronic diarrhoea Unexplained prolonged fever
What are the features of clinical stage 4?
HIV wasting syndrome Pneumocystic pneumonia Toxoplasmosis of the brain
What is the trend in reduction of CD4 and the level of opportunistic infection?
reduction of CD4 increased opportunistic infection
What is the difference between HIV and AIDS?
Certain infections and tumours that develop due to a weakness in the immune system are classified as AIDS illnesses. If you have no symptoms then you have HIV infection only.
What is the correlation between CD4 level and mortality?
Lower the CD4 the higher the mortality risk
What is the natural history of HIV?
Acute infection (seroconversion) - asymptomatic - HIV-related illness - AIDS defining illness - Death
What are the notable features of primary HIV?
Approximately 30 - 60% of patients have a seroconversion illness (when HIV antibodies first develop) Abrupt onset 2 – 4 weeks post exposure, self limiting 1 – 2 weeks Symptoms are generally non-specific
What are the symptoms of primary HIV?
- Flu-like illness - Fever - Malaise and lethargy - Pharyngitis - Lymphadenopathy - Toxic exanthema
What is ART?
Anti-retroviral therapy
When is the best time to start ART?
As soon as they know CD4 is dropping (diagnosis of HIV is suspected)
How has treatment for HIV evolved in the last 10 years?
Multiple medications to now one tablet
What is the action of antiretroviral therapy?
- Different classes of drugs acting on different stages in HIV lifecycle - Combination antiretroviral therapy (cART) means at least 3 drugs from at least 2 groups
What level of adherence is required for successful therapy?
Adherence needs to be over 90% - support patient
How does cART effect life?
On cART can lead to a normal life but side effects can be significant eg metabolic, lipodystrophy
At what sites do these ART treatments act?
- Binding and entry 2. Reverse transcription 3. Integration 4. Transcription 5. Assembly 6. Release and Protease
When do we start ART therapy?
Consider starting all patients at diagnosis regardless of CD4
What are the current life expectancy’s of patients diagnosed aged 20?
<100 : 52 100-200 : 62 >200 : 72
How long does treatment last?
Lifelong
Why do treatment’s fail at points in time?
*Poor adherence leads to viral mutation and resistance* - Inadequate potency - Inadequate drug levels - Inadequate adherence - Pre-existing resistance
Nucleoside reverse transcriptase inhibitor features?
Marrow toxicity, neuropathy, lipodystrophy
Non-nucleoside reverse transcriptase inhibitor features?
Skin rashes, hypersensitivity, drug interactions
Protease inhibitors features?
Drug interactions, diarrhoea, lipodystrophy and hyperlipidaemia.
Integrase inhibitors features?
rashes
How can we prevent HIV?
- Behaviour change and condoms - Circumcision - Treatment as prevention: VL undetectable = untransmissable (pregnancy) - Pre-exposure prophylaxis (PrEP) - Post-exposure prophylaxis for sexual exposure (PEPSE)
