HIV Flashcards
how is HIV spread?
Sexual transmission
Injection drug misuse
Blood products
Vertical transmission
Organ transplant
Think of high risk and unknown risk
Can you test an unconscious patient for HIV?
Unconscious patients can be tested if you think it is in the patient’s interest to have the test
Does having had a negative HIV test does affect insurance premiums
Having had a negative HIV test does not affect insurance premiums
what is the immunology of a HIV infection?
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 disease?
Over course of infection:
CD4 count declines & HIV viral load increases
- Increasing risk of developing infections and tumours
- The severity of these illnesses is greater the lower the CD4 count (normal CD4 > 500)
- Most AIDS diagnoses (severe infections) occur at CD4 count <200
what is the classification of a HIV infection?
Original classification was clinical - this was of considerable help in estimating the incidence of disease in the developing world where HIV testing was less readily available.
Pragmatic approach is to consider symptomatic vs asymptomatic disease
Classification no longer based on having certain clinical features but now based on certain laboratory parameters
Used to have certain illnesses to have AIDs
estimate of the timeline:
Opportunistic infections in HIV
Do I have HIV or 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
Virtually everyone with an AIDS illness should recover from it and then be put on antivirals to keep them free from any future illness
what is the presentation of HIV?
earlier you diagnose it, better the _______
prognosis
What is the Natural history?
Acute infection – seroconversion;
Asymptomatic;
HIV related illnesses;
AIDS defining illness;
Death
Acute infection to death in an untreated patient, 10 years 50% of patients will be dead
What is Primary HIV / seroconversion?
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 generally non-specific and differential diagnosis includes a range of common conditions
What are the symptoms of Primary HIV / seroconversion?
Flu-like illness
Fever - Fever that last over a couple weeks
Malaise and lethargy
Pharyngitis
Lymphadenopathy
Toxic exanthema
“looks like glandular fever but EBV serology not in keeping”
Patients tend to be ill for over a couple weeks where as other viruses tend to get better in a week
Graph showing Treatment of HIV
is there many different options and effective drugs?
yes many
How has the amoubt of pills patients are required to take changed?
Used to have to take lots of pills with lots of restrictions and many side effects
how is Antiretroviral therapy carried out?
Different classes of drugs acting on different stages in HIV lifecycle
Combination antiretroviral therapy (cART) means at least 2 or 3 drugs from at least 2 groups
Adherence needs to be over 90% - support patient
cART can lead to a normal life but side effects can be significant eg metabolic, lipodystrophy, also there can be drug interactions
picture showing where different treatments act
how do they act?
Reverse transcription inhibitors – inhibit viral RNA being transcribed into DNA
Integrase inhibitors – prevent viral DNA being integrated into the host genome
Protease inhibitors – prevent maturation of the virus
When and what treatment do you start?
Nowadays start all patients at diagnosis regardless of CD4 and viral load
- only delay starting if concerned about an immune reconstitution illness e.g. cryptococcal meningitis
- ideally start once baseline genotypic resistance testing known
If CD4 < 350 cells/mm3 patients at risk fo developing symptoms without being on treatment and if CD4 < 200 need to start as soon as possible
Any pregnant woman – start before third trimester
Three drug combination with treatment adjustment if viral load not adequately suppressed after 4-6 weeks
Make sure the drugs are working and if the virus is not coming down usually patients ___ taking pills properly or the virus may be _______
not
resistant
(picture showing resistance testing)
What is the current life expectancy
Life expectancy according to CD4 Nadir (lowest CD4 before starting therapy) in patient diagnosed aged 20
<100 - 52
100-200 - 62
>200 - 70+
Present early = do better
How long will I need to be on treatment?
Once you start treatment you need to continue it for the rest of your life. The treatment may need to be changed from time to time but you will always need to be taking some form of antiviral medication
In many ways, the treatment of HIV is similar to that of a chronic condition (like hypertension) rather than to the treatment of an infection
Even if viral load goes from detectable to undetectable it doesn’t mean you can stop treatment
Why do treatments fail?
If not taking properly then virus isn’t supressed and the viral can mutate against the low level of antivirals it is exposed to then the antivirals become useless
Used to be more of an issue when not as many drugs available
Gain weight when take medication sometimes and some patients don’t like and then stop taking medication
What are some side effects of antiviral drugs?
Nucleoside reverse transcriptase inhibitors - marrow toxicity, neuropathy, lipodystrophy
Non-nucleoside reverse transcriptase inhibitors - skin rashes, hypersensitivity, drug interactions, neuropsychiatric effects
Protease inhibitors - drug interactions, diarrhoea, lipodystrophy and hyperlipidaemia.
Integrase inhibitors - Rashes, disturbed sleep
What is Lipodystrophy and what needs to be done about it?
Change drugs:
- Less likely with newer
- agents
Cosmetic procedures:
- facelift
- liposuction
- fillers
Sometimes offered surgery
Central obesity and loss limb fat
Fat redistribution
Similar to Cushing’s
Distressing side effect
What are the challenges of HIV care in 2019?
osteoporosis
Cognitive impairment
malignancy
Cerebrovascular disease
Renal disease
Ischaemic heart disease
Diabetes mellitus
Age related degenerative conditions
Age faster than rest of population
We need to try and modify their risk to minimise their risk of developing these degenerative conditions
May die earlier from these than compared to the rest of the population
what is HIV prevention?
Behaviour change and condoms
Circumcision
Treatment as prevention - VL undetectable = untransmissable
Pre-exposure prophylaxis (PrEP)
Post-exposure prophylaxis for sexual exposure (PEPSE)
If virus undetectable in blood then it ____ be transmitted
cant
Summary:
Test at any appropriate _________
Combination treatment with good compliance required for disease ______
Treatment probably best form of ________
Early ________ should be associated with a normal life expectancy
opportunity
control
prevention
treatment
