Flashcards in HIV: pathophysiology and presentations Deck (68)
What can HIV cause/lead to?
AIDS - Acquired Immunodeficiency Syndrome
What is the life expectancy of people with HIV?
What is HIV?
Originated in Central/West African chimpanzees
Responsible for pandemic starting in 1981
Originated in West African Sootey mangabey (Simian ID virus)
What is CD4?
CD4+ receptors are the target site for HIV
A glycoprotein found on the surface of a range of cells
What cells are CD4 receptors found on?
T helperlymohocytes (CD4+ cells)
What do CD4+ Th lymphocytes do?
Essential for induction of adaptive immune response
Recognition of MHC2 antigen-presenting cell
Activation of B-cells
Activation of cytotoxic T-cells (CD8+)
What does HIV do to the immune response?
Reduced circulating and proliferating of CD4 cells
Dysregulation expression of cytokines
Increased susceptibility to viral infections
Reduced affinity of antibodies produced
What are HIV sufferers susceptible to?
What is the normal range of CD4+Th cells?
What number of CD4+Th cells give risk to opportunistic infections?
Describe HIV viral replication?
Rapid replication in early and late infection
New generation every 6-12 hours
What is the prognosis of HIV without treatment (on average)?
How does the infection take place?
Infection of mucosal CD4 cell (Langerhans and Dendritic cells
Transport to regional lymph nodes
Infection established within 3 days of entry
Dissemination of virus
How long after infection does it take for symptoms to present?
Usually 2-4 weeks
What are the symptoms of a primary HIV infection?
Headache/ aseptic meningitis
What occurs in asymptomatic HIV infection?
Ongoing viral replication
Ongoing CD4 count depletion
Ongoing immune activation
Risk of transmission
What is the definition of an Opportunistic infection?
An infection caused by a pathogen that does not normally produce disease in a healthy individual. But does when afforded the opportunity by a weakened immune system.
What organism causes Pneumocystis pneumonia and what CD4 count is needed for this?
Organism - Pneumocystis jiroveci
CD4 count: <200
What are symptoms and signs of Pneumocystis pneumonia
Symptoms: insidious onset, SOB, dry cough
Signs: Exercise desaturation
How do you diagnose Pneumocystis pneumonia?
BAL and immunoflourescence +/- PCR
What is the treatment and prophylaxis for Pneumocystis pneumonia?
Treatment: High dose co-trimoxazole (+/- steroid)
Prophylaxis: Low dose co-trimoxazole
What other opportunistic infection that effects the respiratory system can occur in HIV?
What organism causes Cerebral Toxoplasmosis and what CD4 level is needed?
Organism: Toxoplasma gondii
CD4 level: <150
What is cerebral toxoplasmosis?
reactivation of latent infection
Multiple cerebral abscess (Chorioretinitis)
What are symptoms/signs of cerebral toxoplasmosis?
What organism causes Cytomegalovirus and what CD4 count is needed?
CD4 level: <50
What is CMV?
Reactivation of latent infection.