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Source: Anderson PL, Kakuda TN,
Fletcher CV. Human Immunodeficiency Virus Infection. In: DiPiro, JT,
Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM. Pharmacotherapy:
A Pathophysiologic Approach. 8th ed. http://accesspharmacy.com/content.aspx?aid=8006952.
Accessed June 26, 2012.
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- Infection caused by HIV virus
- Hallmark of HIV disease depletion of cluster of differentiation
4 (CD4) cells and associated development of opportunistic infections
and malignancies.
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- HIV an RNA retrovirus, types HIV-1 and HIV-2.
- HIV-1: North America
and western Europe
- HIV-2: western Africa
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- HIV infects cells expressing CD4 (T-helper cell) receptors,
such as:
- T-helper lymphocytes
- Monocytes
- Macrophages
- Dendritic cells
- Brain microglia
- Unrelenting destruction of CD4 cells causes profound immunosuppression
and AIDS.
- RNA-dependent DNA polymerase (reverse transcriptase) transcribes
RNA into DNA.
- Double-stranded DNA migrates into nucleus and is integrated
into host-cell chromosome.
- HIV can establish persistent,
latent infection, inhibiting cure.
- HIV replicates in activated cells.
- Three phases of viral replication and pathogenesis:
- Acute (2–3 weeks)
- Chronic (several years)
- Terminal (acquired immunodeficiency syndrome [AIDS])
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- Infection occursthrough
3 primary modes:
- Sexual:
Most common method for transmission, primarily anal and vaginal
intercourse
- Highest
risk from receptive anorectal intercourse at 0.5–3% per
sexual act
- Condom use reduces risk of transmission by ~20-fold.
- Individuals with genital ulcers or sexually transmitted infections
(STIs) at great risk.
- Parenteral
- Infected
blood exposure from needle sticks, IV injection with used needles,
receipt of blood products, and organ transplants
- Risk of transmission from needle sharing: 0.67% per
episode
- Perinatal
- Most
infections occur during or near time of birth.
- Frequency of breast milk transmission: 4–16%.
- Revised classification systems for adult and child HIV found
in Tables 1 and 2.
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