Flashcards in HIV Deck (39):
are youth afflicted by HIV
yes. 25% of new infections are between 13-24
what is HIV
infection with human immunodeficiency virus
what is AIDS
end-stage HIV infection
is HIV enveloped
how does HIV replicate
via DNA intermediate
where did HIV come from
zoonoses from central and western africa. primate-to-human jumping events. simian is the immediate precursor.
how is HIV transmitted
sexual at genital or colonic mucosa. exposure to infected fluids such as blood. mother-to-infant. accidental occupational exposure.
how does HIV enter the cells?
initial interaction between gp120 and CD4, secondary interaction between gp120 and CCR5. the distal tips of gp41 are inserted into the membrane. gp41 undergoes a significant conformational change and pulls the virus and cellular membranes together, fusing them
steps of HIV replication
fusion > reverse transcriptase synthesizes RNA into DNA > integrase integrates the DNA into the host genome > replication and transcription occur after
why is HIV so successful
because of its remarkable variability. this results in phenotype diversity, immune escape, resistance to RT and protease inhibitors. there is underlying variation caused mutation, high rate of viral turnover, selection of viral variants.
what is the most common source of transmission
male homosexual contact
what are the factors that influence HIV spread
sexual behavior, male circumcision, demography and social context, gender, stigma and discrimination
stage 0 HIV
negative test within 180 of positive test
stage 1 HIV
stage 2 HIV
CD4 cells 200-499 %14-25
stage 3 HIV
CD4 cells <14
bacterial AIDS defining infections
multiple or recurrent bacterial infections, mycobacterium disseminated or extrapulmonary, salmonella species recurrent.
fungal AIDS defining illnesses
candidiasis of esophagus or upper airway, coccidiomycoses disseminated or extrapulmonary, cryptosporidiosis chronic intestinal, histoplamosis disseminated or extrapulmonary, pneumocystis jirovecii pneumonia
viral AIDS defining illness
CMV other than liver, spleen, nodes, CMV retinitis (with loss of vision), progressive multifocal leukoencephalopathy.
parasitic AIDS defining illnesses
isosporiasis, chronic intestinal, toxoplasmosis of the brain
AIDS defining cancers
invasive cervical cancers, karposi sarcoma, lymphoma (burkitt, immunoblastic, brain
what is the clinical presentation of acute HIV infection
fever, weight loss, malaise, headache, neuropathy, pharyngitis, mouth sores, thrush, esophageal sores, myalgia, liver and spleen enlargment, LAD, skin rash, nausea and vomiting.
symptoms of AIDS
meningitis, encephalitis, retinitis, pneumocystis pneumonia, TB, tumors, skin tumors, GI esophagitis, chronic diarrhea, tumors.
what are the clinical suspicions for AIDS
high risk behavior or exposure, febrile illness, mononucleosis syndrome, aseptic meningitis, rash, mucocutaneous ulcers, diarrhea, LAD.
IgM/IgG + p24 antigen time
HIV RNA test
HIV antigen tests?
they have variable sensitivities
35-50 days indeterminate, 45-60 positive
what is in the differential for HIV
mononucleosis, toxoplasmosis, rubella, syphilis, hepatitis, gonococcal infection, lupus or other autoimmune diseases.
what bacterial infections are suspected in HIV patients
recurrent pneumonias, tuberculosis ,
what fungal infections are suspected in HIV patients
jirovecii, and other endemic fungus
what viral and parasitic infections are suspected in HIV
when there is cough and fever in HIV with CD4 count DDX
sinusitis, bronchitis, bacterial pneumonia, tuberculosis
when there is cough and fever in HIV with no CD4 count DDX
PCP, disseminated fungal disease, CMV
small bowel diarrhea
watery large volume, bloating, gas, cramping, weight loss.
large bowel diarrhea
frequency, small volume, painful, weight loss uncommon
history of receptive anal intercourse, severe tenesmus, dyschezia, urgency.