HIV Flashcards
Define localized infection
infections limited to small areas
define disseminated infection
infection that has spread to areas of the body beyond initial location
define systemic infection
infections that have spread throughout the body- often via blood
describe bacteria
bacteria are one celled organisms common throughout nature and within the body
how do bacteria cause disease in the body
entering the body and growing inside human cells
secreting toxins that damage cells
what are the shapes of bacteria?
cocci, bacilli, curved rods, vibrio, spirochetes
What is the structure of viruses
they are infectious particles consisting of RNA or DNA and a protein coat
What are protozoa
single-celled microorganisms that normally live in soil and water. Malaria
What are prions
infectious particles that contain abnormally shaped proteins
typically affect nervous system
Creutzfeldt-jakob disease
define emerging infections
an infectious disease that has recently increased in incidence or that threatens to increase in the immediate future
where do emerging infections originate
unknown sources, contact with animals, changes in known disease, biologic warfare
What are some examples of emerging infections
West nile virus, Ebola, H1N1, lyme disease, PUD, E.coli, HIV, Hepatitis
Examples of Reemerging infections
Diptheria, Pertussis, Plague, TB,
What is resistance
occurs when pathogenic organisms change in ways that decrease the ability of a drug to treat disease
How do microorganisms resist antimicrobial agents?
Mutation
Acquisition of new DNA or RNA
producing enzymes that destroy or inactivate drugs
changing drug target sites
Examples of emerging strains of antibiotic resistant organisms
Methicillin- Resistant S. Aureus (MRSA)
Vancomycin Resistant Enterococci (VRE)
Penicillin-resistant Streptococcus Pneumonia
How do health care providers contribute to the development of drug-resistant organisms
1- administering antibiotics for viral infections
2- succumbing to pressures from pt to prescribe unnecessary antibiotic
3- using inadequate drug regimens to treat infections
4- using broad-spectrum or combination agents that should be treated with first-line medications
How do patients contribute to resistant development
1- skipping doses
2-not taking antibiotics for the full duration
3- saving unused antibiotics
What are Health-care associated infections (HAI)
infections that are acquired as a result of exposure to a microorganism in a health care setting
- up to 10% of pt will get an HAI
how much HAIs are preventable
up to 1/3
What is the first line of defense against an HAI
hand washing, PPE
What is the most common HAI in the elderly population
UTIs especially in patients in nursing homes
Infections in older adults often present what?
atypical symptoms- behavior and cognitive- before normal symptoms (fever/pain) and laboratory findings
when should standard precautions be used?
when in contact with, blood, body fluids, nonintact skin, mucous membranes
What population is HIV more prevelent
men who have sex with men.
How is HIV transmitted?
sexual intercourse, exposure to HIV blood/blood products, perinatal transmission during pregnancy, delivery or breastfeeding
When can an HIV positive person transmit the virus
a few days after becoming infected until death
What are the variables that influence HIV transmission?
duration and frequency of contact with virus
volume, virulence and concentration of organism
host immune status
What is the most common way HIV is transmitted?
through unprotected sex
how has the greater risk of developing HIV during sex
the receiving partner- although the “inserting partner” is still at risk
Why is the receiving partner more at risk of developing HIV during sex
due to prolonged contact with infected fluid
how is HIV transmitted through contact with blood and blood products?
contaminated equipment- sharing equipment
transfusions
What is the most common means of work-related HIV transmission?
puncture wounds- although the risk is till very low
How does the HIV virus enter normal cells?
The gp120 “knobs” on the virus attach to the specific CD4 and chemokine receptors
Once in the cell (usually CD4 T cells) what does the HIV virus do?
viral RNA enters the cell where it is transcribed with the help of a reverse transcriptase into a single strand of viral DNA
What happens next to the single strand of viral DNA?
it copies it self becoming a double strand of viral DNA and enters the cell’s nucleus with the help of the enzyme integrase
Once the double stranded viral strand of HIV is in the nucleus what happens?
The DNA splices itself into the human genome becoming a permanent part of the genetic structure which causes all daughter DNA to have the same DNA and make new HIV
What does the initial HIV infection result in
viremia- large amounts of virus in the blood for a couple of weeks followed by low levels of HIV
what is a major consequence of the rapid replication of HIV
errors can occur in the copying process, causing mutations that can contribute to resistance to ART and limit treatment options
in the initial stages of the HIV infection, how do B cells and T cells respond?
They function normally
B cells make HIV specific antibodies which reduce viral load
T cells mount a cellular response to viruses trapped in lymph nodes
What cells does HIV predominately affect?
CD4+ T cells- which the T cells play an important role in the detection and defense against pathogens
What is the normal CD4+ count in a normal adult
800-1200 CD4+ T Cells/ microliter
what is the normal life span of a CD4+ T cell
100 days
What is the life span of a CD4+ T cell an an HIV person
2 days
When do opportunistic infections occur
when CD4+ count is below 500
What is the pattern that untreated HIV infections follow
1- disease progression is highly individualized
2 treatment can significantly alter this pattern
3- an individual’s prognosis is unpredictable
Symptoms of the Acute infection of HIV
similar to a mononucleousis syndrome
fever, swollen lymph glands, sore throat, headache, malaise, nausea, muscle and , diarrhea, rash accompanies seroconversion- development of antibodies
When do acute HIV symptoms occur
within 2-4 weeks of initial infection and they last 1-3 weeks
During acute infection what is the viral load at?
the viral load is typically high and CD4+ T cells are low but this quickly returns to normal or baseline
what is the interval between initial HIV infection and AIDs
about 10 years
During the asymptomatic infection phase of HIV what is the viral load
the viral load is low and the CD4+ T cell level remains above 500
during the asymptomatic phase of HIV what are some symptoms that may appear?
fatigue, headache, low-grade fever, night sweats, persistent generalized lymphadenopathy
When does symptomatic infection occur in HIV
when the CD4+ T cell count drops to 200-500
What are the symptoms of HIV in the symptomatic infection stage
persistent fever, frequent drenching night sweats, chronic diarrhea, recurrent headaches, and fatigue, localized infections, lymphdenopathy, nervous system manifestations
what is the most common infection associated with the symptomatic phase of HIV infection
oropharyngeal candidasis- thrush
shingles
outbreaks of herpes
oral hairy leukoplakia
What is the diagnostic criteria for AIDS
CD4+ T cells below 200 Opportunistic Infection Opportunistic Cancer - invasive cervical cancer, kaposis sarcoma, burkitt's lymphoma, immunoblastic lymphoma, primary lymphoma of the brain Wasting syndrome AIDS dementia complex
How do you diagnose HIV infection
testing the blood for HIV antibodies or antigen in the blood- typically detects HIV specific antibodies
typically take several weeks
how is the progression of HIV monitored
CD4+ T cell counds and viral load
As HIV progresses what happens to the CD4+ T cell cound
the t cell number decreases
If the viral load is undetectable what does that mean?
that the viral load is lower than the test is able to report
Why are abnormal blood tests common in HIV infections
HIV, opportunistic disease, complications of therapy
why is anemia common in HIV patient
it is associated with the chronic disease process and an adverse effect of ART
What are the two types of resistance tests that can determine if a patient is resistant to drugs used for ART
Genotype Assay- detects drug resistant viral mutations
Phenotype Assay- measures growth of HIV in various concentrations of ART
what is the focus of collaborative care in HIV infected Patients
1- monitoring HIV disease progression and immune function
2- initiating and monitoring ART
3- preventing the development of opportunistic disease
4- detecting and treating opportunistic disease
5- managing symptoms
6- preventing or decreasing complications of treatment
7- preventing further transmission of HIV
What is the goal of drug therapy in HIV infection
1- decrease the viral load
2- maintain or increase CD4+ T cell counts
3- prevent HIV-related symptoms and opportunistic disease
4- delay disease progression
5- prevent HIV transmission
How much can ART reduce viral load
90-99%
What is the advantage of using multiple ART?
is that the combination therapy can inhibit viral replication in several ways making it more difficult for the virus to recover and decreasing the likelihood of drug resistance
what is truvada
truvada is the first drug approved to reduce the risk of HIV in uninfected individuals who are at high risk of HIV
Health Promotion of HIV
prevention of HIV Decreasing risk related to sex Decreasing risk of perinatal transmission decreasing risks at work HIV testing
Acute Intervention of HIV
initial response to diagnosis of HIV
antiretroviral therapy
delaying disease progression
