HIV Flashcards
What are the key receptors involved in thee infection of CD4 cells by the HIV virus?
Viral gp120 attaches to CD4 receptor then binds to CCR5 or CXCR4 coreceptors. viral gp41 is exposed and facilitates fusion and viral entry.
Mortality in HIV/AIDS is usually secondary to….
opportunistic infections,
wasting,
cancer
in a HIV infected pregnant woman, Caesarian delivery is indicated if….
viral load >1000
what is the typical course of HIV infection?
- Primary HIV infection
- Asymptomatic HIV infection
- Symptomatic HIV infection
- Full-blown AIDS
The combination of these two tests in confirming a HIV diagnosis yields an overall sensitivity and specificity of >99%….
ELISA and Western Blot
Phase I: Primary HIV infection
mononucleosis-like syndrome 2-4 weeks after HIV exposure
Duration is brief: 3days-2 weeks
Nonspecific symptoms
High false negative rate due to pre-seroconversion
Phase 2: Asymptomatic HIV infection
Seropositive
No clinical evidence of HIV infection
CD4 counts are normal
Longest Phase: lasts 4-7 years if untreated
Phase 3: Symptomatic HIV infection
first evidence of immune system dysfunction
Phase lasts 1-3 years with out treatment
Characterized by generalized lymphadenopathy, fungal infections, oral hairy leukoplakia, seborrheic dermatitis, constitutional symptoms
Phase 4: Full-blown AIDS
CD4 count
if CD4 count is >500, immune system is…
essentially normal
CD4 level between 200-500
Increased risk of HIV related problems: herpes zoster TB lymphoma bacterial pneumonia kaposi sarcoma
CD4 count
most opportunistic infections occur at this level
Target goal for HIV viral load
want undetectable viral load
How often should viral load and CD4 count be measured?
At time of diagnosis and every 3-4 months afterward
Pro and Con to p24 antigen assay for diagnosing HIV infection
test is less expensive
but it is less sensitive than viral load testing
Patients with acute (primary) HIV infection have very high…
levels of viremia
what is the leading cause of death in AIDS?
Pneumocystis Pneumonia (PCP)
Treatment of PCP
TMP-SMX (trimethoprim/sulfamethoxazole) for three weeks
*If hypoxic or elevated A-a gradient, give steroids
What is the recommended prophylaxis treatment for PCP?
oral TMP-SMX 1 dose daily
TB, CMV, MAC infections are more likely when….
CD4 count
Seroconversion
When patient is positive for HIV antibody
Occurs 3-7 weeks after infection
Confirms HIV diagnosis
IF HIV ELISA is positive, what is the next step?
Confirm with Western Blot Test
HIV Patient with subtle memory impairment and cognitive deficits, followed by changes to mental status, aphasia, and motor abnormalities should be evaluated for….
AIDS dementia
HIV patient with CNS symptoms and head imaging findings of contrast-enhanced mass lesions in basal ganglia and subcortical white matter should be suspected of having…
reactivation of latent toxoplasmosis
How is cryptococcal meningitis diagnosed?
CSF cryptococcal antigen
CSF culture
CSF stain with India Ink
How should cryptococcal meningitis be treated in HIV patients?
amphotericin B for 10-14 days followed by 8-10 weeks of oral fluconazole
*Lifelong maintenance treatment with fluconazole is indicated
Non-infectious CNS diseases in HIV patients:
CNS lymphoma
Cerebrovascular Accidents
Metabolic encephalopathies
The most common GI complaint in HIV patients is….
Diarrhea
What is the most common cause of dysphagia in HIV patients?
Esophageal Candidiasis
Common dermatologic/malignant condition in HIV:
kaposi sarcoma: painless, raised brown-black or purple papules
CMV and HSV infection is seen with CD4 counts….
What is the most important manifestation of CMV infection in HIV patients?
Retinitis: unilateral visual loss that can become bilateral if left untreated
Treatment of CMV infection
ganciclovir or foscarnet
most common opportunistic bacterial infection in AIDS
Mycobacterium avium complex (MAC)
MAC occurs in patients with…
advanced AIDS, CD4
MAC clinical features
Wasting Syndrome: weight loss, fever
Lymphadennopathy
Anemia
Diarrhea
HIV1 Wasting Syndrome
Profound involuntary loss of >10% of body weight in conjunction with either: Chronic Diarrhea (2 daily) or Fever/persistent weakness for more than one month
HIV/AIDS associated malignancies
Kaposi Sarcoma
Non-Hodgkin Lymphoma
Primary CNS Lymphoma
What lab is always elevated in PCP?
LDL level
What is highly activated antiretroviral therapy (HAART)?
Triple Drug Regimens
Target and inhibit HIV replication at three different points
Involves 2 nucleoside RT inhibitors and either NNRTI or protease inhibitor
Nucleoside Reverse Transcriptase Inhibitors Mechanism
competitively inhibit RT by lacking 3’OH group
All are nucleosides and require phosphorylation to be active except tenofovir
Which of the NRTIs are actually nucleotides?
Tenofovir is the only nucleotide
Which NRTI is used in pregnancy?
Zidovudine
NRTI Toxicity
Bone marrow suppression
peripheral neuropathy
Toxicity of Zidovudine
megaloblastic anemia
toxicity of didanosine
pancreatitis
Nonnucleoside RT inhibitors mechanism
noncompetitively inhibits RT
Do not require phosphorylation
NNRTIs include
Efavirenz
Nevirapine
Delaviridine
NNRTI toxicity
RASH
Hepatotoxicity
Efavirenz Toxicity
CNS symptoms
These antiretroviral drugs are contraindicated in pregnancy
Efavirenz and Delaviridine
Protease Inhibitors include:
all that end in -navir
Protease inhibitors mechanism
Inhibit protease so that polypeptide viral products cannot be cleaved and activated
Toxicity of protease inhibitors
Hyperglycemia
hyperlipidemia
GI intolerance
Lipodystrophy
Which antiretrovirals are boosted by inhibiting P450?
Ritonavir Saquinavir
Integrase inhibitor and mechanism
raltegravir
inhibits integration into host cell
toxicity of raltegravir
hypercholesterolemia
Fusion inhibitors includes
enfuviritide
maraviroc
mechanism of enfuviritide
binds gp41 to inhibit entry
mechanism of maraviroc
binds CCR5 to inhibit its interaction with gp120
toxicity of fusion inhibitors
eosinophilia causing skin reaction at injection site
PCP prophylaxis
TMP-SMX when CD4
TB prophylaxis
PPD yearly screening
If PPD is positive give isoniazid and pyridoxine
MAC prophylaxis
start when CD4
Toxoplasmosis prophylaxis
start when CD4
Vaccination guidelines for HIV patients
No live virus vaccines!!!
Pneumovax every 5-6 years Influenza vaccine yearly Hep B vaccine if not already Antibody positive Hep A vaccine Also dTAP if not already immunized
Vaccines that are contraindicated in HIV patients
Varicella zoster intranasal influenza MMR **These are all common live vaccines
Other vaccines to be aware of that are also live vaccines:
vaccinia (small pox), oral poliovirus vaccine, yellow fever and typhoid
Recommendation for Pap tests in women with HIV
Pap test at time of diagnosis, then another one after 6 months. If these two are normal, then proceed to do Paps annually. HIV infected women are at increased risk for infection with high risk strains of HPV, and thus at increased risk of cervical cancer.
