5 Defense and Immunity: Infection and Antimicrobials (Part 2)
5 Defense and Immunity: Infection and Antimicrobials (Part 2)
This chapter is a continuation of the previous chapter.
Learning Objectives
- Identify populations who have an increased risk of infection.
- Describe common pathogens and methods of infection control.
- Distinguish between antimicrobial agents in terms of mechanism of action, indication for use, adverse effects, and implications for the nursing process.
- Apply knowledge of ways to minimize the emergence of drug-resistant microorganisms.
It requires a living host for replication. An invading virus may immediately cause disease or may remain relatively dormant for years. Diseases develop as a result of interference with the normal cellular functioning of the host, with the destruction of the virus by the immune system also requiring the death of the host cell.
Review of Prior Knowledge: Viruses
The learner needs to draw from previously learned knowledge to better understand pathophysiologic and pharmacologic conditions. The following videos are USEFUL RESOURCES for your review:
- Human immunodeficiency virus (HIV): Human Immunodeficiency Virus (HIV) is a retrovirus that attacks the body’s immune system, specifically the CD4 cells (T cells), which are crucial for immune function. If left untreated, HIV can lead to Acquired Immunodeficiency Syndrome (AIDS), the most severe phase of HIV infection, where the immune system is severely compromised, making the body vulnerable to opportunistic infections and certain cancers. Antiretroviral therapy is used for pharmacologic management of HIV.
HIV Infection
Pathophysiology
1. Entry and Infection: HIV targets and enters CD4 cells by binding to the CD4 receptor and co-receptors (CCR5 or CXCR4) on the cell surface. Once inside the cell, the viral RNA is reverse-transcribed into DNA by the enzyme reverse transcriptase.
2. Integration: The enzyme integrase then integrates the newly synthesized viral DNA into the host cell’s genome. This allows the virus to hijack the host cell’s machinery to produce new viral particles.
3. Replication: The infected CD4 cell produces viral proteins and RNA assembled into new virions. These new virions are then released from the host cell, ready to infect other CD4 cells.
4. Immune System Impact: Over time, HIV reduces the number of CD4 cells, weakening the immune system. This depletion leads to increased susceptibility to opportunistic infections and certain cancers, which define the progression to AIDS if left untreated.
Stages of HIV Infection
1. Acute HIV Infection: This is the initial stage of infection, occurring 2 to 4 weeks after exposure. Symptoms of the flu may resemble fever, swollen lymph nodes, sore throat, rash, muscle and joint aches, and headache. High levels of virus are present in the blood, making the individual highly infectious.
2. Chronic HIV Infection: Also known as the asymptomatic or clinical latency stage, this period can last for several years. The virus is still active but reproduces at ver