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Course Sample:
INTRODUCTION
Since the early 1980s when the Human immunodeficiency virus (HIV) was first identified the virus and the ultimate deterioration of the immune system have been extensively studied and researched. Progress has been made in prolonging life and improving quality in many of the HIV-infected persons. The development of AIDS, an acronym for acquired immunodeficiency disease syndrome, becomes the diagnosis after a person infected with HIV develops one of the Center for Disease Control (CDC)-defined indicator diseases and/or whose CD4 count is less than 200 cells/mm3. HIV/AIDS is a world wide epidemic affecting nearly 40 million people, more than 70% of whom live in sub Saharan African and another 16% live in South and Southeast Asia. Statistics from December 2000 indicate that there are an estimated 900,000 people infected with HIV currently living in the U.S. Among new HIV infections approximately 70% occur in men, with males having sex with males representing the largest portion at 42%. Men and women infected through heterosexual sex and IV drug use comprise 33% and 25% respectively. More than half of new HIV infections are diagnosed among African-Americans. The incidence among Hispanics is rising. Among women the incidence of HIV is highest among African-American females who become infected through heterosexual contact. AIDS is the fifth leading cause of death in the U.S. among those aged 25-44. As of December 2000 there have been over 448,000 deaths due to the HIV epidemic. Today HIV/AIDS is still not curable and is considered a chronic condition that ultimately ends in death of the infected individual. (CDC, 2002). http://www.cdc.gov/hiv/stats/hasr1301.htm
At least two strains of the virus have been identified, HIV-1 and HIV-2. . The virus mutates rapidly and, for this reason, developing a vaccine and new drugs to treat the infection is a challenge to researchers. In order to understand the implications for nursing care of clients with HIV disease this article will include a review of the immune system and pathophysiology of HIV, differentiation of HIV versus AIDS, risk factors for transmission of the virus, diagnostic and laboratory testing, clinical manifestations of Primary HIV infection and opportunistic infections and diseases (OI), treatment, prevention measures, psychosocial and ethical concerns, nursing responsibilities, and ongoing research for HIV/AIDS.
Review of Immune system as related to HIV
The body's primary defense against invasion by pathogens such as viruses, bacteria, and parasites is controlled by the immune system, that is a complex network of cells, tissues, and organs that must all be functioning optimally in order to provide necessary protection. The major cells of the immune system are the white blood cells (WBC) which include several different immune cells all of which are derived from the pluripotent stem cell. Neutrophil is the most numerous of the WBCs and along with the macrophage initiate the primary response to invasion of the body by pathogens. Two types of lymphocytes are the B cell and T cell. These cells make up the specific immune response mechanism. The B cell is responsible for the antibody antigen response, also called humoral immunity, by recognizing specific antigens and producing antibodies to respond to specific antigens. The cell mediated immunity (CMI) has multiple functions and uses the T cell in concert with the B cells to provide protection from pathogens not accessible to antibodies, such as viruses, intracellular bacteria and parasites. CMI also acts an immune system regulator, a surveillance mechanism for cancer cells, and stimulates phagocytosis. The CMI is the component of the immune system that is most directly affected by HIV virus and is the part of the immune system most capable of reducing the spread of the virus.
The T cell has several subsets that are important to understand with regard to HIV. The T4
(T helper cell or CD4), and the T8 (T suppressor cell or CD8), have an important function in regulating the immune response. (**CD4 is the receptor molecule of the T4 helper cell and is used synonymously.) The normal level of CD4 is between 500 and 1500 cells/mm3. The normal ratio of T4 : T8 (CD4:CD8) is 2:1. If the number of CD4 cells drops the immune response is suppressed and the individual becomes less likely to be able to fight an infection or kill off non-self cells. The T Helper cells (CD4) are the major target cell of the virus that causes HIV/AIDS although B cells and macrophages are also infected by HIV.
Pathophysiology of HIV
The identification of the causative agent that produced the disease to be known as AIDS occurred in 1984 and was labeled human immunodeficiency virus type 1. Three years later a second type, HIV-2, was isolated in patients with AIDS in West Africa. Both viruses have similar modes of transmission and similar opportunistic infections (OI) while there are differences in disease progression and epidemiology of the diseases.
HIV-1 is the more prevalent disease in the U.S. HIV-1 is a retrovirus that invades the host cells and releases its genetic RNA material into the host cell. The viral RNA is then converted into DNA by a viral enzyme called reverse transcriptase (RT). This process initiates the numerous changes that occur within the host cell that permit the virus to duplicate/reproduce HIV viruses. Another viral enzyme, integrase assists to split and insert the viral DNA into the host cell's chromosomes. The new viral DNA thus moves into the nucleus of the cell and integrates with the DNA of the host cell that is now part virus. The genetic material of the infected cell is now able to produce new viral RNA in the form of large protein molecules. Another viral enzyme called protease assists the breakdown of the large viral particles into smaller components that make the changed host cell (now a part virus cell) infectious (Wilson, 1997). The newly infected helper cells undergo lysis or cell destruction and the virus is released to infect other cells. The importance of understanding the three viral enzymes will become clearer as we investigate pharmacological therapies for HIV/AIDS.
The HIV infected cells thus become virus producing factories. The rate of viral reproduction has been estimated at 10 million virions daily (Ungvarski & Matassarin-Jacobs, 1997). The targeted cells release the virus into the blood stream and go on to infect other cells. With the destruction of the host cells, primarily the CD4 or Helper T cells, the immune response becomes ineffective. When the CD4 count falls below 200 cells/mm3 the HIV infected person is said to have AIDS. The ability of the body to fight common pathogens and cancer cells is seriously diminished. The greater the loss of CD4 cells the more likely there will develop opportunistic infections (OI). The Center for Disease Control established a CD4 cell count below 200/cubic ml as an indicator of high risk for development of opportunistic infections/diseases. The healthy immune system is able to protect the invasion of many organisms that normally coexist in various organs of the body such as in the GI and respiratory tracts, mucous membranes, and skin. With the destruction of the helper cells and the deterioration of the immune response, these organisms now produce deadly infections and cancers known as OI.
Risk factors and Transmission of HIV
The CDC has estimated that there are 900,000 people with HIV/AIDS living in the U.S. and probably one-third of these people do not know that they are infected. (HIV Prevention: Policy Facts). The primary transmission of the HIV virus is through infected blood or semen. Since the lymphocytes are the primary target cells for the virus the body fluids that have higher concentrations of these white cells will be the most infectious such as semen and blood. Therefore the risk factors and behaviors for acquiring the HIV virus include:
- IV drug use with shared needles
- Males having unprotected sex with other males
- Unprotected sex with HIV infected individual
- Having other sexually transmitted diseases
- Received a blood transfusion or blood clotting factor between 1978 and 1985.
- Unprotected sex with any of the above.
- Having multiple sex partners
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