HIV Pathology & Presentation Flashcards
(59 cards)
What type of virus is HIV?
RNA Retrovirus - means it uses reverse transcriptase to transcribe copies of itself
What type & group of HIV was responsible for global epidemic?
HIV-1 Group M
HIV 2 is mostly localised to ____ and is ____ virulent than HIV-1.
West Africa, less virulent than HIV-1
At what stages of infection is there rapid replication and how often is there new generation?
Very early and very late stage
every 6-12 hours
Through what types of surface does HIV usually transfer?
Across mucosal surfaces e.g. vaginal, cervix or rectum
or percutaneous, or can be break in integrity of mucosa
How does infection occur?
infection of mucosal CD4+ (Langerhans & dendritic) cells that bring it across mucosa to regional lymph nodes after which it is disseminated e.g. to GALT, brain and spleen
After how long is infection established after entry into the body?
Within 3 days of entry
What is the target site for HIV?
CD4+ receptors
What is CD4 and on list 4 cells it is found on.
Cluster of Differentiation - a glycoprotein found on the surface of cells e.g. T helper lymphocytes, dendritic cells, macrophages, microglial cells
HIV can affect them but mostly t helper
Which type of cell has the specific CD4+ receptor?
T helper lymphocytes
What are 4 main roles of CD4+ T Helper lymphocytes in the induction of adaptive immune response?
recognition of MHC2 antigen-presenting cell, activation of B-cells, activation of cytotoxic T-cells (CD8+), cytokine release
List the effects of HIV infection on CD4+ cells, CD8+ cells, antibodies and the immune system overall.
reduced numbers and quality of CD4+ cells, increased number but reduced activation of CD8+ cells, reduced affinity of antibodies produced (not quite right) and chronic immune activation - overall some parts of immune system in overdrive and some depleted
What can cause Chronic Immune Activation in HIV?
Response to infection or microbial translocation from depleted GALT (bugs getting across gut barrier)
What are HIV +ve patients susceptible to?
viral, fungal, parasitic & mycobacterial infection , infection-induced cancers
What is normal parameter for CD4 Th cells?
500-1600 cells/mm3
What is parameter for highest risk of opportunistic infections in HIV?
<200 cells/mm3
Outline the overview of CD4+ cell levels in untreated HIV infection.
Initially in first 6 weeks CD4+ cells steeply decline, gradually increase a small bit in 6-12 weeks then very gradually decline over the next 11 years.
What is the average time to death without HIV treatment?
9-11 years
Approx. 80% of patients present with symptoms at their primary infective stage. What is the average time between infection and onset of symptoms?
2-4 weeks
List 5 symptoms that patients may experience in primary HIV infective stage?
- fever
- rash (maculopapular)
- myalgia
- pharyngitis
- headache/aseptic meningitis
During the asymptomatic HIV infective stage there is ongoing viral replication, ongoing CD4 count depletion and ongoing immune activation. However, there is no risk of onward transmission. True/false?
False- first part all true but there is risk of onward transmission
An opportunistic infection is caused by a pathogen that does not normally produce in a healthy individual. List some AIDS-defining conditions. (6)
Pneumocystic pneumonia, TB, cerebral toxoplasmosis, cytomegalovirus, HIV-associated neurocognitive impairment, PML
What is the organism of PCP and at what CD4 threshold does it tend to occur?
pneumocystis jiroveci, <200
What are the signs and symptoms of pneumocystis pneumonia?
symptoms: insidious onset, SOB, dry cough
Signs: chest may sound normal, exercise oxygen desaturation
