Flashcards in HIV Deck (70)
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1
What is HIV?
Retrovirus
HIV-2 originated in West African Sootey mangabey
Less virulent
HIV-1 originated in Central/West African chimpanzees: HIV1 group M responsible for global pandemic
2
What is the target site for HIV?
CD4+ receptors
3
What cells are CD4+ receptors found on?
T helper lymphocytes
Dendritic cells
Macrophages
Microglial cells
4
What do CD4+Th lymphocytes do?
Essential for induction of adaptive immune response
Recognition of MHC2 APC
Activation of B cells
Activation of cytotoxic CD8+ T cells
CK release
5
What effect does HIV infection have on immune response?
Sequestration of cells in lymphoid tissues
-Reduced circulating CD4+ cells
Reduced proliferation of CD4+ cells
Reduction CD8+ (cytotoxic) T cell activation
-Dysregulated expression of cytokines
-Increasing susceptibility to viral infections (including HIV)
Reduction in antibody class switching
-Reduced affinity of antibodies produced
Chronic Immune Activation (microbial translocation)
6
What does HIV increase susceptibility to?
Viral infections
Fungal infections
Mycobacterial infections
Infection-induced cancers
7
At what CD4+Th count is there a risk of opportunistic infection?
<200cells/mm3
Normal is 500-1600
8
Describe HIV viral replication
Rapid in very early and very late infection
New generation every 6-12hours
9
How does HIV spread in the body?
Infection of mucosal CD4 cell (Langerhans/dendritic)
Transport to RLNs
Infection established within 3 days of entry
Dissemination of virus
10
When is the usual onset of HIV?
2-4wks after infection
11
What are the common symptoms of primary HIV infection?
Fever
Rash (maculopapular)
Myalgia
Pharyngitis
Headache/aseptic meningitis
Up to 80% present with symptoms
12
What happens during the asymptomatic HIV infection?
Ongoing replication
Ongoing CD4 count depletion
Ongoing immune activation
Risk of onward transmission if remains undiagnosed
13
What is an opportunistic infection?
An infection caused by a pathogen that does not normally produce disease in a healthy individual. It uses the “opportunity” afforded by a weakened immune system to cause disease
14
What organism causes pneumocystis pneumonia?
Pneumocystis jiroveci
15
What are the symptoms and signs of pneumocystis pneumonia?
Insidious onset
SOB
Dry Cough
Exercise desaturation
16
How is pneumocystis pneumonia diagnosed?
CXR: May be normal, interstitial infiltrates, reticulonodular markings
BAL and immunofluorescence +- PCR
17
What is the treatment and prophylaxis for pneumocystis pneumonia?
Rx- High dose co-trimoxazole (+- steroid)
Proph: Low dose co-trimoxazole
18
What tuberculosis infections/conditions are more common in HIV+ than HIV- individuals?
Symptomatic primary infection
Reactivation of latent TB
Lymphadenopathies
Miliary TB
Extrapulmonary TB
Multi-drug resistant TB
Immune reconstitution syndrome
19
What organism causes cerebral toxoplasmosis?
Toxoplasma gondii
20
What happens in cerebral toxoplasmosis?
Reactivation of latent infection
Multiple cerebral abscess (chorioretinitis)
21
What are the symptoms/signs in cerebral toxoplasmosis?
Headache
Fever
Focal neurology
Seizures
Reduced consciousness
Raised intracranial pressure
22
What does CMV cause?
Retinitis, colitis, oesophagitis
23
How does CMV present?
Reduced visual acuity
Floaters
Abdo pain
Diarrhoea
PR bleeding
24
What skin infections can be due to HIV?
Herpes Zoster: Multidermatomal, Recurrent
Herpes Simplex: Extensive, Hypertrophic, Aciclovir resistant
Human papilloma virus: Extensive, Recalcitrant, Dysplastic
Penicilliosis
Histoplasmosis
25
What causes HIV-associated neurocognitive impairment?
HIV-1
26
How does HIV-associated neurocognitive impairment present?
Reduced STM
+- motor dysfunction
27
What causes progressive multifocal leukoencephalopathy?
JC virus
Reactivation of latent infection
28
How does progressive multifocal leukoencephalopathy present?
Rapidly progressing
Focal neurology
Confusion
Personality change
29
What are some other neurological presentations of HIV?
Distal sensory polyneuropathy
Mononeuritis multiplex
Vacuolar myelopathy
Aseptic meningitis
Guillan-Barre syndrome
Viral meningitis (CMV, HSV)
Cryptococcal meningitis
Neurosyphilis
30
What causes HIV-associated wasting aka Slim's Disease?
Metabolic (chronic immune activation)
Anorexia (multifactorial)
Malabsorption/diarrhoea
Hypogonadism
31
What causes Kaposi's sarcoma?
Human herpes virus 8 (HHV8)
32
What is the basic pathology of Kaposi's sarcoma?
Vascular tumour
33
How does Kaposi's sarcoma present?
Cutaneous
Mucosal
Visceral- pulmonary, GI
34
What is the treatment for Kaposi's sarcoma?
HAART
Local therapies
Systemic chemotherapy
35
What causes Non-Hodgkins lymphoma?
EBV (Burkitt’s lymphoma, primary CNS lymphoma)
36
How does Non-Hodgkins lymphoma present?
More advanced
B symptoms
Bone marrow involvement
Extranodal disease
Increased CNS involvement
37
What should be offered to all with complicated HPV disease?
HIV testing
38
How can cervical cancer present?
Recalcitrant warts
High grade CIN, VIN, AIN, PIN
39
What are the clinical features of non-OI symptomatic HIV?
Mucosal candidiasis
Seborrhoeic dermatitis
Diarrhoea
Fatigue
Worsening psoriasis
Lymphadenopathy
Parotitis
Epidemiologically linked conditions: STIs, Hepatitis B, Hepatitis C
40
What are some haematologic manifestations of HIV?
Anaemia
Thrombocytopenia
41
What are the modes of transmission of HIV?
Sexual
Parenteral
Mother to Child
42
What factors increase transmission risk of HIV in sex?
Anoreceptive sex
Trauma
Genital ulceration
Concurrent STI
43
How does parenteral transmission of HIV occur?
Injection drug use (sharing 'works')
Infected blood products
Iatrogenic
44
How does MTCT of HIV occur?
In utero/trans-placental
Delivery
Breast-feeding
45
What is the sex ratio of HIV?
2.1:1 M:F
46
What risk group has the highest proportion of HIV in the UK?
MSM
47
What services include an opt-out HIV test?
TOP services
GUM
Drug dependency services
Antenatal services
Assisted conception services
48
What high risk groups should regular HIV screening be carried out on?
MSM
Female partners of bisexual men
IVDU
Partners of people living with HIV
Adults, children, sexual partners, and people with history of iatrogenic exposure from/in an endemic area
49
What are the high prevalence areas of HIV?
Sub-Saharan Africa
Caribbean
Thailand
50
When HIV falls within the DDx what should be performed regardless of risk factors?
HIV test
Risk assessment not necessary
51
What is important when taking an HIV test of an incapacitated person?
Only test if in patients best interest
Consent from relative not required
If safe, wait until patient regains capacity
Obtain support from HIV team if required
52
Which markers of HIV are used by labs to detect infection?
RNA (viral genome)
Envelope proteins (gp120)
Capsule protein (p24)
53
What do 3rd generation HIV tests detect?
HIV 1+2 antibody
IgM
IgG
54
What is the window period of 3rd generation HIV tests?
Avg. 20-25 days
55
What do 4th generation HIV tests detect?
Combined antibody and antigen (p24)
56
What is the window period of 4th generation HIV tests?
14-28 days
57
What is the recent infection testing algorithm?
Can be used to identify if an infection occurred within the preceding 4-6months
58
How does RITA work?
Measure different types of antibodies or strength of antibody binding- HIV1, subtype B
59
What are the targets for anti-retroviral drugs?
Reverse transcriptase
Integrase
Protease
Entry: fusion, CCR5 receptor
Maturation
60
What was shown to have in vitro activity against HIV?
Nucleotide analogues reverse transcriptase inhibitors (NRTI) e.g. zidovudine
61
What is highly active anti-retroviral therapy (HAART)?
A combination of three drugs from at least 2 drug classes to which the virus is susceptible
62
What is most important in preventing drug resistance in HIV?
Adherence
63
What are the S/Es of HAART?
GI S/Es (protease inhibitors), transaminitis, fulminant hep (nevirapine, most others)
Skin: rash, HS, SJS (abacavir, nevirapine)
CNS: mood, psychosis (efavirenz)
Renal: proximal renal tubulopathies (tenofovir, atazanavir)
Bone: osteomalacia (tenofovir)
CVS: increased MI risk (abacavir, lopinavir, maraviroc)
Haematology: anaemia (zidovudine)
64
What enzymes do protease inhibitors interact with?
Liver enzyme inhibitors
65
What enzymes do NNRTIs interact act with?
Liver enzyme inducers
66
Describe partner notification and disclosure in HIV
Voluntary process- may takes weeks, months, years
Duty of care to a known third party
67
How can you prevent onward HIV sexual transmission?
Condom use
HIV treatment
STI screening and treatment
Sero-adaptive sexual behaviours
Disclosure
Post-exposure prophylaxis
Pre-exposure prophylaxis
68
What are conception options for an HIV+ male, HIV- female?
Timed unprotected sex with HAART
Treatment as Prevention
69
What are conception options for an HIV+ female, HIV-male?
? Self-insemination
Timed unprotected sex with HAART
Treatment as Prevention
70
