HIV/AIDS. Flashcards
what is the epidemiology of HIV?
HIV -peak incidence of age 20-30
AIDS - peak incidence a 45
incidence is higher in black population
HIV prevalence is highest in south of the continent of africa africa - Botswana
species
HIV -1 - MOST COMMON SPECIES WORLDWIE
HIV-2 - RESTRICTED ALMOST COMPLETELY TO WEST AFRICA
what is the FAMILY AND GENUS AND SPECIES of HIV virus ?
family - retroviridae
genus - lentivirus
species
HIV -1 - MOST COMMON SPECIES WORLDWIE
HIV-2 - RESTRICTED ALMOST COMPLETELY TO WEST AFRICA
what are the CHARACTERISTICS of HIV virus ?
structure - icosahedral with a conical capsid and a spiked envelope
genome
pseudolipid - 2 RNA molecule and 1 DNA molecule
HIV is a retrovirus, meaning that its genome is stored in the form of RNA
9 geners encoding 15 proteins
what are the routes of transmission of HIV
sexual
higher in men - men sex
depends also on viral load
reduce infection in circumscised men - cornification of the penis glans, thus reducing the likelihood of lesions during intercourse
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parenteral transmission
needle sharing
blood transfusions
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vertical transmission -
during childbirth
breast feeding
what is the pathophysiology of HIV ?
there is a WINDOW PERIOD
HIV enters the body - attached to cd4 receptor on target cells
such as t lymphocytes and macrophages , monocytes and dendritic cells
the viral envelop fuses with the host cell for the viral caspid to enter
a virions RNA is transcribed into dsDNA
and then integrated into the hosts dna
viral DNA is replicated and virions are assembled
virions leave the cell using the hosts cell membrane through budding causing cell death
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chronic immunodeficiency
HIV infects cd4+ lymphocytes and spreads to
CD4+ lymphocytes concentrated in specialized lymphoid tissue (e.g., lymph nodes or gut-associated lymphatic tissue (GALT) ) → explosive growth and dissemination → acute HIV syndrome with high viral load
=Acute HIV syndrome does not develop in all patients. Absence of symptoms may delay diagnosis.
time between infection and detectability of HIV antibodies.
After the acute stage, viral load decreases and remains at roughly that level for approximately 8–10 years =clinical latency stage = Corresponds to a chronic persistent infection
During the clinical latency phase, the virus mainly replicates inside the lymph nodes.
Increasing loss of CD4+ lymphocytes (especially T cells) impairs immune function and, thereby, facilitates opportunistic infections and development of malignancies (AIDS)
Viral load predicts the rate of disease progression and CD4 count correlates with immune function.
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incubation period for HIV?
usually 2–4 weeks
what are the infectious period of HIV
Infectiousness: two peaks (1st peak: within the first months after infection; 2nd peak: during AIDS-stage)
what are the clinical manifestations of HIV ?
no clinical features specific to HIV infection
arly HIV infection, patients are often asymptomatic.
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acute hiv syndrome
described as a mononucleosis-like syndrome
// Fever // // Fatigue // Myalgia and arthralgia
Generalized nontender // lymphadenopathy //
Generalized rash Gastrointestinal symptoms (nausea, diarrhea, weight loss)
Oropharyngeal symptoms (sore throat, ulcerations, painful swallowing)
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clinical latency and AIDS
Clinical latency: Infected individuals may still be asymptomatic.
Non-AIDS-defining conditions :
Chronic subfebrile temperatures
Persistent generalized lymphadenopathy
Chronic diarrhea (> 1 month)
Localized opportunistic infections
Oral candidiasis: creamy, white patches on the mucous membranes of the mouth that can be scraped off
Vaginal infections (e.g., yeast, trichomonads)
Oral hairy leukoplakia: lesions that cannot be scraped off located on the lateral borders of the tongue; triggered by Epstein-Barr virus
HPV-related: squamous cell carcinoma of the anus (common in men who have sex with men) or cervix
Skin manifestations (e.g. molluscum contagiosum, warts, exacerbations of psoriasis, shingles)
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AIDS - defining condition
when cd4 count gets so low
HIV wasting syndrome - Unintentional weight loss of ≥ 10%, fatigue, fever, diarrhea
Kaposi sarcoma - caused by human herpes 8
cervical cancer invasive - hpv
lymphoma - CNS lymphoma ebv -
reactivated tuberculosis
cryptosporidosis - chronic watery diarrhoea , nausea an abdominal pain
HIV related encephalopathy
pneumocystis pneumonia
cerebral toxoplasmosis
candiasis
HIV classification
WHO
primary HIV infection - acute hiv syndrome or asymptomatic
clinical stage 1 - persistent generalised lymphadenopathy or asymptomatic
clinical stage 2 - unexplained moderate weight loss less than 10 percent , recurrent fungal/ viral/ bacterial infections
clinical stage 3 - unexplained severe weight loss >10 percent chronic diarrhea >1 month persistent efever >37.6 persistent infections anemia , neutropenia
clinical stage 4 - AIDS defining conditions - kaposi sarcoma , pneumocystispneumonia etc
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diagnosis of HIV?
screening tests :
1) combination antigen and antibody testing -
fourth generation ELISA based test
detect both HIV antigens and anti- HIV antibodies - IgG
if negative rules out HIV
or
2) HIV serology - antibody only detecting tests
ELISA
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CONFIRMATORY TESTS
1 ) HIV-1/2 antibody diffrentiatal immunoassay
can detect both HIV-1 and HIV-2 in ∼ 20 minutes and distinguish between the two types
no longer recommends western blot tests for confirmation of HIV infection.- Tests may be negative for up to 2 months after infection.
Results are usually available after several days
HIV subtype O is not reliably detected.
2) Detection of viral RNA
detect HIV infection earlier than antibody/antigen-based tests, but FDA-approved tests are limited to HIV-1
indicated :Neonatal HIV infection
Patients with indeterminate results
Combination antigen/antibody tests screening tests is not recommended in whom and why ?
Not recommended for suspected neonatal HIV infection (results may be false-positive due to maternally transferred anti-HIV antibodies)
Viral RNA load test should be done in case of suspicion of perinatal HIV infection
what is the treatment with HIV
1) antiretroviral therapy (cART) as soon as possible
prioritised in :
Low CD4 count
High viral load
Presence of AIDS-defining illness
Therapy should be determined based on the HIV genotype
All antiretroviral drugs are able to target both HIV-1 and HIV-2, except for enfuvirtide and NNRTIs
=========== recommended regime 3 NRTI (NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS ) or 2 NRTI + 1 NNRT1 ( ) NONNUCLEOSIDE REVERSE-TRANSCRIPTASE INHIBITORS ) / 1 PL (protease inhibitors) / 1 NI (Integrase inhibitors ) /
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ANTIRETROVIRAL DRUGS
1) NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS
eg Zidovudine
Lamivudine
:( = Bone marrow suppression: anemia (especially zidovudine), neutropenia
Mitochondrial toxicity leading to :
Myopathy
Peripheral neuropathy
2) NONNUCLEOSIDE REVERSE-TRANSCRIPTASE INHIBITORS
eg Nevirapine
Efavirenz
:( = Hepatotoxicity (nevirapine)
CNS toxicity and vivid or disturbing dreams (efavirenz)
3) HIV protease inhibitors
eg Indinavir
Ritonavir
:( = GI upset (nausea, diarrhea)
Lipodystrophy and fat accumulation ,
Nephrolithiasis, crystal-induced nephropathy, and hematuria
Hyperglycemia:
4) Integrase inhibitors (NI)
eg Raltegravir
Dolutegravir
:( = ↑ creatine kinase
5) Entry inhibitors
binding or fusion of HIV virions with human cells.
Enfuvirtide
:( : skin irritation at the site of drug injection
Maraviroc
:( hepatotoxicity, allergic reactions
what re the complications of HIV ?
Immune reconstitution inflammatory syndrome
caused by Combined antiretroviral therapy
what are the prevention methods for HIV ?
preexposure prophylaxis
Eligibility
- Negative HIV test result and no signs or symptoms of acute
- HIV infection
- Normal renal function test
at least one indication criteria:
Men who have sex with men
anal sex without condoms in the past 6 months
A bacterial STI (syphilis, chlamydia, or gonorrhea) diagnosed or reported in the past 6 months
Heterosexual men and women
Sexually active with an HIV positive partner
Inconsistent or no condom use during sexual activity with one or more sexual partners of unknown HIV status
Intravenous drug users with high-risk needle behavior (e.g., sharing needles/equipment) or
Timing: Prior to the exposure to HIV and continued for a month after the exposure.
Drugs
Emtricitabine + tenofovir disoproxil fumarate (TDF-FTC)
OR Emtricitabine + tenofovir alafenamide (TAF-FTC)
Follow-up
HIV test every 3 months
Renal assessment at baseline and every 6 months
Counseling on adherence and risk reduction
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HIV post-exposure prophylaxis
Indications
- Injury with HIV-contaminated instruments or needles
- Contamination of open wounds with HIV-contaminated fluids
- Unprotected sexual activity with a known or potentially HIV-infected person
Initiate as soon as possible (ideally within one to two hours after exposure)
Drugs: A three-drug regimen is recommended
. Typically, this includes a
NRTI (NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS)
+
an integrase inhibitor:
- Tenofovir-emtricitabine + dolutegravir
- Tenofovir-emtricitabine + raltegravir
after needle stick injury or other contamination :
1) Let the wound bleed.
2) Rinse/flush with water and soap and/or antiseptic agent.
3) Immediately seek medical attention.
