3. HIV Flashcards
How is HIV Spread?
- Sexual Transmission
- Injection Drug Misuse
- Blood Products
- Vertical Transmission
- Organ Transplant
Can you test unconscious patients for HIV?
Yes, if you think it is in the patient’s best interest
What does the HIV infection do to the immune system?
It infects and destroys cells of the immune system, especially the T-Helper cells that are CD4+
What does a T-Helper Cell, that is CD4+ mean?
The T-Helper Cell has a CD4 receptor on its surface
Are CD4 receptors exclusive to lymphocytes?
No, they are also present on the surface of:
1. Macrophages and Monocytes
2. Cells in the Brain
3. Cells in the Skin
and many other sites
Over the course of the HIV infection, what happens to the
1. CD4 count?
2. HIV Viral load?
- The CD4 count declines
- The HIV Viral load increases
Over the course of the HIV infection, what happens to the risk of developing infections / tumours?
They increase
How does the severity of the illness relate to the CD4 count?
The severity of the illness is greater, the lower the CD4 count
At what CD4 count do most AIDS diagnoses occur at?
Less than 200
What does a low CD4 count, allow for?
Opportunistic infection
What are Opportunistic infections?
Pathogens which are capable of causing infection only when the host defences are compromised
In HIV, what are the 2 categories of Opportunistic infections?
- New infections (e.g. PCP, cryptosporidiosis)
- Re-activation of existing infection (e.g. toxoplasmosis CMV)
What are the most common New Opportunistic Infections, in HIV?
- Pneumocystis Jiroveci Pneumonia
- Candidiasis
- Mycobacterium Avium Complex
- Cryptosporidiosis
What are the most common Re-Activated Opportunistic Infections, in HIV?
- Cerebral Toxoplasmosis
- Tuberculosis
- CMV disease
What is the natural history of HIV infection?
- Acute infection - seroconversion
- Asymptomatic HIV
- HIV related illness
- AIDS defining illness
- Death
What is the CD4 count between in Asymptomatic HIV?
400+
Note - Normal is 1000-1500
What happens as the CD4 count drops below 350?
- Thrust is likely
- Skin changes
What happens as the CD4 count drops below 200?
Other opportunistic infections can arise:
1. PCP
2. TB
3. Cryptospondiosis
4. Kaposis Lymphoma
5. Toxicoplasmosis
6. Cryptococcal Meningitis
7. CMV, MAC
What is a Seroconversion Illness?
When HIV antibodies first develop
What are the symptoms of Primary HIV (Seroconversion Illness)?
Like Glandular Fever, but EBV Serology is not in keeping:
1. Flu-like illness
2. Fever
3. Malaise / Lethargy
4. Pharyngitis
5. Lymphadenopathy
6. Toxic Exanthema
How is the length of duration of this illness calculated?
- If had a seroconversion illness then date is from then
- Test stored samples of blood (if available)
- Considering when the patient was at most risk
Is stage of the illness at presentation helpful in estimating duration of infection?
No
What is an AIDS illness?
Infections and Tumours which develop due to a weakened immune system
If there are no symptoms, does the patient have HIV or an AIDS illness?
HIV infection only
Do most people with an AIDS illness (HIV + infection / tumour) recover?
Yes
What are Respiratory AIDS-defining conditions?
- Tuberculosis
- Pneumocystis
What are Neurology AIDS-defining conditions?
- Cerebral Toxoplasmosis
- Primary Cerebral Lymphoma
- Cryptococcal Meningitis
- Progressive Multifocal Leucoencephalopathy
What are Dermatology AIDS-defining conditions?
Kaposi’s sarcoma
What are Gastroenterology AIDS-defining conditions?
Persistent Cryptosporidiosis
What are Oncology AIDS-defining conditions?
Non-Hodgkin’s Lymphoma
What are Gynaecology AIDS-defining conditions?
Cervical Cancer
What are Ophthalmology AIDS-defining conditions?
Cytomegalovirus Retinitis
How is HIV infection monitored?
- CD4 Lymphocyte Count
- HIV Viral Load
- Clinical Features
What do the different classes of drugs, used to treat HIV infection, act on?
Different stages of the HIV life-cycle
- What is the treatment used to treat HIV infection?
- What does this mean?
- Combination Antiretroviral Therapy (cART)
- 3 Drugs from at least 2 Groups
What percentage adherence does there need to be to support the patient?
90%
Note - this will lead to a normal life but side effects may be significant (e.g. metabolic, lipodystrophy etc.)
- When should cART be started?
- Should the drug combination be changed?
- If the CD4 Count falls below 350 cells/mm3 or rapidly falling
- Yes, if the Viral Load is not adequately suppressed after 4-6 weeks
What is the life expectancy according to according to CD4 count of:
1. < 100?
2. 100-200?
3. >200?
- 52 years old
- 62 years old
- 70+
How long will you need to be on treatment for a HIV infection?
For life
Will the treatment for HIV infection remain constant throughout the rest of the patients life?
No, it may need to be changed from time to time but some form of medication will also be included
Note - this is the same as treating any other chronic condition
Why do treatments fail?
Poor adherence leads to Viral Mutation and Resistance
What are the 3 main types (groups) of drugs used to treat HIV infection?
- Reverse Transcriptase Inhibitors
- Integrase Inhibitors
- Protease Inhibitors
What are the 4 main types of anti-viral drugs (used in cART)?
- Nucleoside Reverse Transcriptase Inhibitors
- Non-Nucleoside Reverse Transcriptase Inhibitors
- Protease Inhibitors
- Integrase Inhibitors
Where doe Reverse Transcriptase Inhibitors act?
During the “Reverse Transcription” Stage - As the Viral DNA tries to manipulate the host DNA
Where doe Integrase Inhibitors act?
During the “Intergration” Stage - The integration of the Viral DNA into the Host DNA
Where doe Protease Inhibitors act?
During the “Release and Protease” Stage - preventing exit from the host
What are the side effects of Nucleoside Reverse Transcriptase Inhibitors?
- Marrow Toxicity
- Neuropathy
- Lipodystrophy
What are the side effects of Non-Nucleoside Reverse Transcriptase Inhibitors?
- Skin rashes
- Hypersensitivity
- Drug Interactions
What are the side effects of Protease Inhibitors?
- Drug Interactions
- Diarrhoea
- Lipodystrophy
- Hyperlipidaemia
What are the side effects of Integrase Inhibitors?
Rashes
What can be done to reverse the Lipodystrophy (side effect of some HIV medication)?
- Change drugs
- Facelift
- Liposuction
- Fillers
What is the relationship between Cardiovascular Disease and HIV?
- Increased incidence of M.I. (through unknown mechanism)
- Hyperlipidaemias
- Insulin Resistance
What are the main challenges of HIV care in modern times?
- Osteoporosis
- Cerebrovascular Disease
- Cognitive Impairment
- Ischemic Heart Disease
- Renal Disease
- Malignancy
- Diabetes Mellitus
What is the best method of HIV prevention?
- Behaviour change and condoms
- Circumcision (50% reduction)
- Treatment as prevention
Note - if the Viral Load is undetectable, transmission risk is 1 in 100,000 - Pre-exposure Prophylaxis (PrEP)
- Post-exposure Prophylaxis for Sexual Exposure (PEPSE)