HIV Flashcards
Most likely cells affected by HIV
primary targets for HIV are dendritic cells in the mucosa of the genital tract, use receptor DC-sign to attach
What are the receptors for HIV?
CD4 moleucles on the surface of a subpopulation of t-lymphocytes (a coreceptor is needed for infection)
Pathogenesis of HIV
Newly infected lymphocytes flood the blood and are transported to all tissues with in days; there is a progressive annual loss of CD4 cells
How is HIV transmitted?
predominantly through heterosexual intercourse (0.1-1% chance), can be transmitted through HIV infected blood transfusion (100%), child of mother with out tx (30%), needle prick (1/300)
Signs and symptoms of primary HIV infection (acute retroviral syndrome)
incubation period of 2-4 weeks; fever, painful ulcers/lesions, nonexudative pharyngitis and swollen LN (diffuse lymphadenopathy), GI complaints, skin rash (upper body)-2-3 days after fever, HEADACHE
What is the hallmark of HIV infection?
progressive reduction in CD4 T cells (rarely returns to normal)
HIV testing
Diagnosed by the detection of HIV specific antibodies in the plasma or serum. (ELISA) Antibodies appear a few weeks afer infection, shortly before or after symptoms of acute retroviral syndrome. There is a WINDOW PERIOD where patient is infected but its not detected. These antibodies remain positive for LIFE. Do not use PCR.
How do we confirm a dx of HIV
second blood sample, if indeterminate do a western blot to confirm
AIDS defining illness
When the number of CD4 cells declines below a critical level of 200 or they have an AIDs associated syndrome (candidiasis, ____, ____). Patients CD4 count indicates the degree of immune deficiency and predicts short term risk of oppurtunistic disease. In long term- prognosis is also determines by viral load.
When do we consider HAART therapy?
if CD4 is between 350-500
Indications for starting tx
atients CD4 count indicates the degree of immune deficiency and predicts short term risk of oppurtunistic disease. Viral load = more rapid progression. Need to account for speed of progression, patients acceptance of tx, likelihood of compliance and possible side effects.
Tx of HIV
combo therapy: 4 different classes of drugs to tx AIDs: Nucleoside reverse transcriptase (NRTI), Non-nucleoside reverse transcriptase (NNRTI), Protease inhibitors, Fusion inhibitor enfurvitide.
How do we pick the Tx
2 NRTI’s and one of the others
Occupational blood exposure risks
percutaneous injury (needle stick, cut) OR contact of mucous membrane or nonintact skin. Recommendations: Gloves handwashing, etc. Post exposure prophylaxis (w/in hrs) and follow up testing.
Efficacy of Tx monitoring
monitored by decline in viral load and rise in CD4 count (get this done every 3 mo)
What predicts the duration of viral supression?
Nadir- lowest point of viral load reached during tx; time to optimal supression depends on initial viral load.
When to initiate prophylaxis with PCP
CD4 <400 or after episode of PCP
What to give as prophylaxis for PCP
trimethoprim-sulfamehoxazole
When to initiate prophylaxis with Toxoplasma
if CD4 <100
What to give as prophylaxis for Toxoplasma
trimethoprim-sulfamehoxazole
When to initiate prophylaxis of Mycobacterium avian intracellulare
primary prophylaxis if CD4 <100
What to give as prophylaxis of Mycobacterium avian intracellulare
Azithromycin
When to initiate prophylaxis of Cryptococcus
CD4 <50; only in regions of high incidence
What to give as prophylaxis for Cryptococcus
Fluconazole
