HIV: what, how, who? Flashcards
(26 cards)
what is AIDS?
-causes what 2 major pathologies (2)
Acquired immunodeficiency syndrome
-oppertunistic infections
AIDS- related cancers
What is HIV?
A retrovirus
HIV-2
HIV-1, originated from chimps, caused global pandemic
What is CD4?
-relevance of the receptors?
It is a glycoprotein found on surface of: T helper lymphocytes, Dendritic cells, Macrophages, Microglial cells
-CD4+ receptors are the target site for HIV
What do CD4+ Th lymphocytes do?
induce the adaptive immune response (recognition of the MHC2 antigen-presenting cell Activation of B-cells Activation of cytotoxic T-cells cytokine release)
What effect does HIV infection have on immune response? (5)
-means susceptibility to what? (4)
-sequestration of cells in lymphoid tissue
(reduction in circulation CD4 cells)
-reduced proliferation of CD4 cells
-Reduction in CD8+ (cytotoxic) T cell activation
(disregulated expression of cytokines & increased susceptibility to viral infections)
-Reduction in antibody class switching
(reduced affinity of antibodies produced)
-Chronic immune activation
(microbial translocation)
-viral inf, fungal inf, mycobacterial infections, infection induced cancers
CD4+ T cell parameters:
- normal?
- risk of opportunistic infection?
- 500-1600 cells/mm3
- <200 cells/mm3
Describe the immmunopathogenesis in terms of Viral load and CD4 level in:
- early infection?
- after 6 weeks
- late stage?
- what is the incubation period, why is this clinically relevant?
- Massive spike in viral load and then CD4 cells
- viral load comes down and cells recover but not to premorbid level
- virus load increases again and the CD4 count plummets, eventual death without treatment
- infection established within 3 days of entry, this is the window in which you can start them on prophylaxis
Primary HIV infection
- how long does it take for people to present after infection?
- presentation?
- risk of transmission?
-up to 80% present with symptoms 2-4 weeks after infection
-Fever maculopapular rash Myalgia Pharyngitis Headache/aseptic meningitis
-very high risk of transmission
Asymptomatic HIV infection
- what happens with viral replication?
- CD4 count?
- is there a risk of transmission?
- ongoing
- CD4 count depletion
- risk of transmission ongoing
Opportunistic infection
- definition?
- Give examples of the organisms that cause these
infection caused by a pathogen that does not normally produce disease in a healthy individual, uses the opportunity of a weakened immune system to cause disease
-Pneumocystis jiroveci TB Toxoplasma gondii CMV herpes zoster Herpes simplex Human papilloma virus HIV-1 JC virus
Pneumocystis pneumonia
- Causative organism?
- CD4 threshold?
- symptoms? (3)
- signs? (1)
- CXR appearance?
- Dx via what 3 tests?
- treatment & Prophylaxis? (2)
- Pneumocystis jiroveci
- <200
-insidious onset
SOB
Dry cough
- exercise desaturation
- normal or interstitial infiltrates, reticulonodular markings
-BAL & immunofluorescence
+/- PCR
-High dose co-trimoxazole (+/- steroids)
low dose co-trimoxazole
list the symptoms of TB that are more common in HIV+ individuals?
symptomatic primary infection Reactivation in latent TB Lymphadenopathy Military TB Extra pulmonary TB Multi drug resistant TB Immune reconstruction syndrome
cerebral toxoplasmosis
- causative organism?
- CD4 threshold?
- symptoms & signs? (6)
- what is seen on MRI? (1)
- Toxoplasma gondii
- <150
-headache fever focal neurology seizures reduced consciousness raised intracranial pressure
-ring enhancing lesions in brain
Cytomegalovirus
- causative organism?
- CD4 threshold?
- causes? (3)
- presentation? (3)
- CMV
- <50
- retinitis, Colitis, oesophagitis
-reduced visual acuity
floaters
Abdo pain, diarrhoea, PR bleeding
name the organisms more likely to cause skin infection? (5)
Herpes Zoster Herpes simplex HPV Penicilliosis Histoplasmosis
HIV associated Neurocognitive impairment
- organism?
- CD4 threshold?
- presentation? (2)
- HIV-1
- Any: increased incidence with increased immunosuppression
-reduced short term memory
+/- motor dysfunction
Progressive multifocal leukoencephalopathy
- Organism?
- CD4 threshold?
- presentation? (4)
- JC virus & reactivation of latent infection
- <100
-Rapidly progressing
focal neurology
Confusion
Personality change
What are the other neurological presentations of HIV? (8)
Distal sensory polyneuropathy Mononeuritis multiplex Vacuolar myelopathy Aseptic meningitis Guillan-Barre syndrome Viral meningitis (CMV, HSV) Cryptococcal meningitis Neurosyphilis
What are the aetiologies of HIV-associated wasting? (4)
Slims disease metabolic anorexia malabsorption Hypogonadism
Name 3 AIDs related cancers?
-and the causative organisms
Kaposi's sarcoma (HHV8) Non-hodgekins lymphoma (EBV) Cervical cancer (HPV)
Give symptoms of HIV that don’t occur due to opportunistic infection?(8)
Mucosal candidiasis Seborrhoeic dermatitis Diarrhoea Fatigue Worsening psoriasis Lymphadenopathy Parotitis \+ STIs, Hep B/C etc
Haematologic manifestations? (2)
Anaemia
Thrombocytopenia
What 3 ways can HIV be transmitted?
Sexual transmission (increased risk in unreceptive sex, trauma, Genital ulceration, Concurrent STI) Parenteral transmission (in IV drug users) Mother to child
What groups of patients should be tested for HIV? (5)
What groups of patients should be screened? (4)
TOP GUM clinics Drug dependency services Antenatal services Assisted conception
-MSM
female partners of Bi men
IV drug users
Partners of HIV+
