HIV Flashcards
How is HIV spread?
sexual transmission - multiple partners - MSM Injection drug misuse Blood products (haemophiliacs etc) Vertical transmission Organ transplant
What does HIV do to the body?
Infects and destroys of the immune system, especially T helper cells that are CD4+
What does CD4+ mean?
Have a CD4 receptor on their surface
What are CD4 receptors present on the surface of?
LYMPHOCYTES macrophages and monocytes Cells in the brain skin probably many other sites
Over the course of the infection, relationship between CD4 count and HIV viral load
CD4 declines and viral load increases
Normal CD4 count
> 500
What CD4 count do most AIDs diagnoses occur at?
< 200
As the viral load increases, what is there an increased risk of?
Developing infections and tumours
Levels of CD4 over time of infection
The immune system brings the virus under control after a while -> until the HIV RNA increases
Then the CD4 starts to plummet -> this is where you get symptoms and opportunistic infections
What does AIDs stand for?
Acquired immune deficiency syndrome
Clinical stages and their presentations of HIV
Clinical stage I
- asymptomatic
- persistent generalised lymphadenopathy
- performance scale 1 (asymptomatic, normal activity)
Clinical stage II
- weight loss < 10% of body weight
- minor mucocutaneous manifestating (fungal nail infections, recurrent oral ulcerations, seborrheic dermatitis)
- herpes zoster (within last 5 years)
- recurrent URTIs
- and/or performance scale 2 (symptomatic, normal activity)
Clinical stage III
- weight loss > 10% of body weight
- unexplained chronic diarrhoea > 1 month
- oral candidiasis (thrush)
- oral hairy leucopenia
- pulmonary TB within past year
- severe bacterial infections
- and/or performance score 3 (bedridden <50% of the day during the last month)
Clinical stage IV
- HIV wasting syndrome
- Toxoplasmosis of brain
- pneumocystic cariniipneumonia
- Cryptospiridosis with diarrhoea > 1 month
- CMV disease of an organ other than liver, spleen or lymph nodes
- HSV (mucocutaneous > 1 month, visceral any duration)
- PML
- candidiasis of oesophagus, trachea, bronchi or lungs
- atypical mycobacteriosis, disseminated
- extrapulmonary TB (lymphoma)
- HIV encephalopathy
- And/or performance score 4 (bedridden > 50% of the day during the last month)
What is the average time on average from getting HIV to progressing to AIDs?
7-8 years
What is the time on average from AIDs to dying?
Roughly 2 years
What would be classified as an AIDs illness?
Certain infections and tumours that develop due to weakness in the immune system
If have no symptoms, do you have an HIV or an AIDs illness?
No symptoms = HIV illness only
AIDs defining conditions for an adult infection
TB, pneumocisitis Cerebral toxoplasmosis, PML Cryptococcal meningitis Kaposi's sarcoma Peristen cryptosporidiosis Non-hogkin's lymphoma Cervical cancer Cytomegalovirus retinitis
Relationship between CD4 count and mortality
The lower the CD4 count, the higher the mortality
Natural history of HIV infection
- acute infection
- asymptomatic
- HIV related illness
- AIDs defining condition
- Death
What happens during a seroconversion illness?
The HIV antibodies are first developing
Presentation of HIV seroconversion illness
Like a dose of glandular fever that lasts longer and has associated features Diarrhoea Rashes liver dysfunction malaise lethargy pharyngitis lymphadenopathy toxic exanthema
When after exposure does seroconversion illness occur?
2-4 weeks after exposure time
What does ART stand for?
Antiretroviral therapy
Before the CD4 count drops to what do you want to start ART?
approx. 320
what is key to ART to work?
Adherence needs to be over 90%
Types of antivirals
AZT DDI DDC 3TC D4T
When to start ART?
consider starting all patients at diagnosis regardless of CD4
If CD4 > 350 = can start later depending on circumstance e.g. going off shore
If pregnant = start before the third trimester
Can pregnant women with HIV have normal vaginal delivery?
Yes - if the viral load is undetected
Treatments of HIV fail due to….
Poor adherence (leading to viral mutation and resistance) Incomplete suppression - inadequate potency - inadequate drug levels - inadequate adherence - pre existing resistance
What does CD4 nadir mean?
Lowest CD4 before starting on therapy
Life expectancy of a patient diagnosed at 20 with a CD4 nadir of <100
52 y/o
Life expectancy of a patient diagnosed at 20 with a CD4 nadir of 100-200
62 y/o
Life expectancy of a patient diagnosed at 20 with a CD4 nadir of > 200
70+ y/o
Even in well controlled HIV, what seems to accelerate and what does this result in?
Your ageing is accelerated Results in more likely to develop the following at a younger age - osteoporosis - cognitive impairment - malignancy - cerebrovascular disease - renal disease - ischaemic heart disease - DM
HIV prevention
Behaviour change Condoms Circumcision (resource poor settings) Treatment as a prevention Pre-exposure prophylaxis (PrEP) Post-exposure prophylaxis (PePSE)
Treatment of PJP
Co-trimoxazole
Treatment of toxoplasmosis
Co-trimoxazole
Steriods
When to test for HIV after sex?
3 months
What is in an ART for HIV?
Nucleotide reverse transcriptase inhibitor
Non nucleotide reverse transcriptase inhibitor
Protease inhibitor
Integrade inhibitor
Side effects of ART
GI upset
Rash
Neuropathy
What is the most common opportunistic infection in AIDs?
PJP
What does PJP stand for?
Pneumocystitis jiroveci
Who should receive PJP prophylaxis?
All HIV patients with CD4+ count < 200
Presentation of PJP
SOB
Dry cough
Fever
Very few chest signs
Complications of PJP
Pneumothorax
How common is extra pulmonary manifestations of PJP and what are they?
RARE - 1-2%
Hepatosplenomegaly, lymphadenopathy, choroid lesions
Investigations of PJP
CXR
Exercise induced desaturation
BAL
Treatment of PJP
Co trimoxazole
IV pentamidine in severe cases
Steroids if hypoxic
Causative organism of Kaposis sarcoma
HHV-8 (human herpes virus 8)
Who is kaposis sarcoma seen in?
HIV patients
Presentation of kaposis sarcoma
Purple plaques or paperless on skin or mucosa (e.g. GI or resp tract)
Resp involvement may lead to massive haemoptysis and pleural effusion
Treatment of kaposis sarcoma
Radiotherapy
Resection
What are the HIV neuro complications?
Toxoplasmosis Primary CNS lymphoma TB Encephalitis Crypto coccus PML AIDs dementia complex
What % of cerebral lesions in patients with HIV are due to toxoplasmosis?
50%
Presentation of toxoplasmosis
Systemic symptoms
Headache
Confusion
Drowsiness
Investigation of Toxoplasmosis
CT
Thallium spect
What is seen on CT in toxoplasmosis?
Ring enhancing lesions
Mass effect may be seen
Thallium spect status in toxoplasmosis
-ve
Treatment of toxoplasmosis
Sufadiazine and Pyrimethamine
What % of cerebral lesions does primary CNS lymphoma make up?
30%
What is primary CNS lymphoma assosiated with?
EBV
Investigation for primary CNS lymphoma
CT
What is seen on CT for primary cerebral lymphoma?
Single or multiple homogenous enhancing lesions
Treatment of primary CNS lymphoma
Steroid (decrease tumour size)
Chemo
+/- whole brain irridation
Surgery may be considered for lower grade tumours
Thallium spect status of primary CNS lymphoma
+ve
TB brain effects due to HIV - is it common and what is the investigation and what would it show?
Much less common than toxoplasmosis or primary CNS lymphoma
CT - single enhancing lesion
What may encephalitis be due to?
CMV or HIV itself
How common is HSV encephalitis in the context of HIV
Relatively rare
Investigation of encephalitis in HIV and what would it show?
CT - oedematous brain
What is the most common fungal infection of the CNS?
Crypto coccus
Presentation of cryptococcus
Headache Fever Malaise N + V Seizures Focal neurological deficit
Investigations of cryptococcus
LP
CT
What would LP and CT show in cryptococcus?
LP - increased opening pressure and India ink test +ve
CT - meningeal enhancement, cerebral oedema
Typical presentation of cryptococcus but what can it also present as?
Meningitis but can also present as a SOL
What does PML stand for?
Progressive multifocal leukoencephalopathy
Pathology of PML
Widespread demyelination due to infection of oligodendrocytes by JC virus
Presentation of PML
Subacute onset Behavioural change Speech Motor Visual impairment
Investigations for PML and what would be seen
CT - single or multiple lesions, no mass effect, doesn’t usually enhance
MRI - high signal demyelination white matter lesions seen
What is AIDs dementia complex caused by?
HIV itself
Presentation of AIDs dementia complex
Behavioural changes
Motor impairment
Ix for AIDs dementia complex and what would it show
CT - cortical and subcritical atrophy
PEP for HIV
Oral ARVT for 4 weeks
