HIV Flashcards
What types of virus is HIV
retrovirus
What disease can HIV cause
Acquired Immunodeficiency Syndrome AIDS
what are the 2 types of HIV
HIV 1 - responsible for global pandemic
HIV 2 - less virulent, West Africa
What does HIV target molecularly
CD4+ receptors
Which cells contain CD4+ receptors
T helper lymphocytes (CD4+ cells)
microglia
dendritic cells
macrophages
What are the functions of CD4+ cells
activate CD8+ cells
activate B cells
recognise MHC II APCs
cytokine release
What is the normal CD4+ cell count
500-1600 cells/mm3
below which level of CD4+ cell count is opportunistic infection a risk?
CD4+ < 200 cells/mm3
How long is the window of opportunity to prevent HIV after exposure
72 hours
when is the onset of primary HIV
2-4 weeks after infection
How can primary HIV present
fever myalgia rash pharyngitis headaches
Is viral replication still occurring in asymptomatic HIV
Yes, despite having no symptoms, virus continues to replicate and there is CD4+ cell count depletion
Define opportunistic infection
an infection caused by a pathogen that does not normally cause disease in a healthy individual
What is the most common opportunistic infection in HIV
Pneumocytis pneumonia
What organism causes pneumocystis pneumonia
Pneumocystis jirovecii / PCP
At what CD4+ cell count does pneumocystis pneumonia occur
<200
Prophylaxis for PCP is given to those with CD4+ <200, true or false
TRUE
With low dose co-trimoxazole
How does pneumocytsis pneumonia present
insidious onset
SOB
dry cough
How can the CXR appear in PCP
normal
may look like CCF, infiltrative rather than lobular pathology
What investigations can be done for PCP
Exercise desaturation - exercising causes tachycardia and reduced O2 saturation
CXR
Bronchoalveolar lavage + immunofluorescence
+- PCR
What is the management of pneumocystis pneumonia
High dose co-trimoxazole (+steroid if hypoxic)
Latent TB can reactivate with co-existing HIV, true or false
TRUE
What organism causes cerebral toxoplasmosis
toxoplasmosis gondii
levels below which CD4+ cell level puts you at risk of cerebral toxoplasmosis
CD4+ <150 cells/mm3
How does cerebral toxoplasmosis appear on imaging
Ring enhancing lesions
What are symptoms of cerebral toxoplasmosis
headaches fever ^ICP focal neurology seizures reduced consciousness
Below which level of CD4+ cell count is CMV a risk?
< 50 cell/mm3
What screening occurs in those with CD4+ < 50
ophthalmic screening
What are symptoms of CMV infection
retinitis colitis - abdominal pain, PR bleeding, diarrhoea oesophagitis reduced visual acuity floaters in vision
Features of Herpes Zoster viral infection in those with HIV
multidermatomal rashes
recurrent
Features of Herpes simplex viral infection in those with HIV
extensive and hypertrophic
aciclovir resistant
What other weird skin infections can occur in HIV
penicillosis
histoplasmosis
What is HIV associated neurocognitive impairment
reduced short term memory with motor dysfunction
brain atrophy
can occur at any CD4+ cell level
What is progressive multifocal leukoencephalopathy
PML is a rapidly progressing disease with focal neurology and confusion and personality change
What causes PML
JC virus
below which CD4+ cell level does PML occur
<100 cells/mm3
What other conditions may be associated with HIV
distal sensory polyneuropathy Guillain barre syndrome mononeuritis multiplex vascular myelopathy aseptic meningitis cryptococcal meningitis neurosyphilis
What is Slim’s disease
HIV associated wasting - cachectic appearance
Give examples of AIDS related cancers
Kaposi’s sarcoma
Cervical cancer
Non-Hodgkins lymphoma
What virus causes Kaposi’s sarcoma
human herpes virus 8 (HHV 8)
Describe Kaposi’s sarcoma
Spongy, purple tumours vascular tumours occur at any CD4+ cell count cutaneous, mucosal, visceral eg skin, nails, palate, lungs, guts
Which virus causes Non-Hodgkins lymphoma
Eptein Barr virus EBV
Describe Non-Hodgkins lymphoma
Can occur at any CD4+ count
bone marrow involvement
B symptoms
Which virus causes cervical cancer
Human papilloma virus HPV
List some non-opportunistic HIV features
mucosal candidiasis (Oral, oesophageal) seborrhoeic dermatitis (eczema and fungal) diarrhoea fatigue worsening psoriasis lymphadenopathy parotitis epidemiologically linked STIs
List some haematological diseases in HIV
Anaemia of chronic disease
thrombocytopaenia
can occur at any CD4+ level
Describe modes of transmission of HIV
Sexually transmitted - MSM, W+M
Parenterally transmitted - PWID, infected blood products, iatrogenic
Mother to child transmission - in utero, delivery, breast feeding
List methods of identifying those with HIV
Universal screening - high prevalence areas
Opt out testing - certain clinical settings
Screening - high risk groups
Clinical indicative testing - HIV is a differential
What are the markers of HIV
Antibody testing
Antigen p24
Viral RNA
What is 3rd generation testing
HIV 1+2 antibody testing
detects IgM and IgG
3 months window period
What is 4th generation testing
combined antibody and antigen p24 testing
shorter window period
A negative 4th generation test performed at 4 weeks post exposure is highly unlikely to exclude HIV, true or false
FALSE, it is likely to exclude HIV
What is the rapid HIV test
POCT
fingerprick blood test
results in 20-30 minutes
Describe the life cycle of HIV
HIV infects CD4+ cells via CCR5 receptor
HIV membrane fuses with CD4+ cell membrane
Reverse transcriptase converts viral RNA to DNA
Integrase incorporates viral genome into the host cells
Replication of genetic material occurs
Assembly
Protease cleaves DNA which then buds off to make new vesicles
Give types of reverse transcriptase target medications
Nucleoside Reverse Transcriptase Inhibitors NRTIs
Non-Nucleoside Reverse Transcriptase Inhibitors NNRTIs
Nucleotide Reverse Transcriptase Inhibitors NtRTIs
What other medications are used in HIV
Protease inhibitors
Integrase inhibitors
Fusion inhibitors
CCR5 inhibitors
Mono and dual therapy is effective, true or false
FALSE
they are ineffective due to increasing resistance
Define HAART
Highly Active Anti Retroviral Therapy
combination of a minimum of 3 drugs from at least 2 drug classes that HIV is susceptible to
What are the aims of HAART
Reduce viral load to undetectable
Restore immunocompetence
Reduce morbidity and mortality
What is the single most important factor in taking HIV treatment
Adherence
What are some toxic effects of HAART
GI - transaminitis, fulminant hepatitis CNS - sleep disorders, psychosis, mood Skin - rash, hypersensitivity Renal - stones, proximal tubulopathies Bone - osteomalacia CVS - MI risk Haematology - anaemia
Protease inhibitors are potent liver enzyme inducers/inhibitors?
inhibitors
NNRTIs are potent liver enzyme inducers/inhibitors?
Inducers
Partner notification is a voluntary process, true or false
TRUE
List methods of preventing transmission
Condoms HIV treatment STI screening and treatment partner disclosure PEP - Post exposure prophylaxis PrEP - Pre exposure prophylaxis
Can couples with HIV conceive normally
Yes as long as they are on HAART
explain reasons for different delivery methods in pregnant mothers with HIV
undetectable load –> vaginal birth
detectable load –> c-section
How long does a neonate get PEP for
4 weeks
Breast feeding is allowed in HIV mothers, true or false
FALSE, breast feeding is absolutely contraindicated
What are the eligibility criteria for PrEP
>= 16yo HIV negative commits to 3 monthly appointments willing to stop if eligibility criteria no longer apply Scottish resident
What are the high risk factors for getting HIV
HIV + partner with detectable load
MSM
UPAI >=2 partners in last year and likely to do so again in next 3 months
confirmed bacterial rectal STI in last year
other high risk factors
