Flashcards in HIV Deck (43):
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)
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
When to initiate prophylaxis with Toxoplasma
if CD4 <100
What to give as prophylaxis for Toxoplasma
When to initiate prophylaxis of Mycobacterium avian intracellulare
primary prophylaxis if CD4 <100
What to give as prophylaxis of Mycobacterium avian intracellulare
When to initiate prophylaxis of Cryptococcus
CD4 <50; only in regions of high incidence
What to give as prophylaxis for Cryptococcus
When to initiate prophylaxis of Candida
What to give as prophylaxis of Candida
When to initiate prophylaxis of Cytomegalovirus
CD4 <50, secondary if after retinitis
What to give for prophylaxis of CMV
reactivation of latent toxoplasma infection. Starts with focal deficit (hemiplegia), convulsions, headaches, fever or confusion. CD4 IS BELOW 200
Dx of Toxoplasma encephalitis
Toxoplasma IgG antibody will be positive. CT or MRI (w/ gadolinium/contrast) will show abscesses that are usually multiple and preferentially located in the basal ganglia and corticomedullary junction. USUALLY HAS MARKED EDEMA
Tx of Toxoplasma encephalitis
combo of otal sulfadiazine and oral pyrimethamine w/folic acid to prevent bone marrow toxicity (also prevents PCP). Tx is not well tolerated
Pneumocysitis Jiroveci Pneumonia
PCP, subacute disease that develops in HIV infected patients with CD4 below 200.
Symptoms of PCP
fever, dyspnea on exertion, dry cough, weight loss and fatigue. Pulm exam is normal
Dx of PCP
CXR- usually shows interstitial butterfly pattern. Lactate dehydrogenase is usually elevated and PaO2 depressed.
Tx of PCP
fever, head ache, +/- meningeal signs, NO NECK STIFFNESS
Cryptococcal Meningitis Dx
on CD4 <100; blood and LCR are positive
Tx of cryptococcal meningitis
Before advent of HAART, 35-30% of AIDS pts developed this infection. Visual symptoms—blurred vision, scotomas, floaters, or flashing lights— subacute onset.
Retinal findings of CMV retinitis
Mix of exudates, hemorrhages, and atrophy; Vascular sheathing
Tx of CMV retinitis
Tx is required to prevent progression to retinal detachment and blindness. Ganciclovir is drug of choice; causes bone marrow toxicity, and dosing must be corrected for renal dysfunction.
most frequent opportunistic pathogen in all HIV positive patients with severe immunosuppression. Yellow white plaques (thrush). Often accompanied by esophagitis