Care of Patients with HIV Disease and Other Immune Deficiencies

Chapter 21 Care of Patients with HIV Disease and Other Immune Deficiencies




Learning Outcomes



Safe and Effective Care Environment



Health Promotion and Maintenance



Psychosocial Integrity



Physiological Integrity



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Immune system function is concerned with helping the body stay healthy by preventing the growth of infectious organisms and abnormal cells, such as cancer cells. It assists the body to monitor and maintain those cells and substances that are considered “self,” belonging to the body. For example, newly made cells and compatible blood transfusions are deemed self and safe by the immune system. However, when the immune system detects the presence of a protein or cell that does not belong to the body and represents a potential threat, its job is then to attack and destroy the “non-self” or “foreign” substance. Infection is a major threat. We are exposed to many organisms every day. The efficiency of the immune system prevents disease despite this exposure.


When the immune system fails to recognize infectious agents, severe local and systemic infections are not suppressed or controlled. Immune system failure can be the result of a primary (congenital) immune deficiency in which one or more parts of the system are not functioning properly from birth. These problems are usually genetic mutations that are discovered in the infant or child who is repeatedly sick. Immune system failure can also be secondary (acquired after birth) as the result of viral infection, contact with a toxin, or medical therapy. These problems can cause a normal immune system to stop functioning or to function less efficiently. In either case, the immune system can no longer distinguish what should be in the body from a foreign invader. The consequences for the immune-deficient patient can range from mild, localized health problems to total immune system failure, leaving the body open to attack from any foreign pathogen.



Acquired (Secondary) Immune Deficiencies



HIV InFection and AIDS



Pathophysiology


Human immune deficiency virus (HIV) infection can progress to acquired immune deficiency syndrome (AIDS), which is the most common secondary immune deficiency disease in the world (World Health Organization [WHO], 2010). First identified in 1981, HIV/AIDS is now a serious worldwide epidemic.



Etiology and Genetic Risk


The cause of HIV infection is a virus—the human immune deficiency virus. Like most viruses, HIV is a parasite looking for a way into a cell, to take over the cell, and to force the cell into making more copies of the virus. These new virus particles then look for additional cells to infect, repeating the cycle as long as there are new host cells to infect.



The HIV Infectious Process

Viral particle features include an outer envelope with special “docking proteins,” known as gp41 and gp120, that assist in finding a host (Fig. 21-1). Inside, the virus has two protein coatings and the genetic material along with the enzymes reverse transcriptase (RT) and integrase. The first challenge is for the HIV particle to get inside a host cell. HIV accomplishes this task by first finding a way into the host’s bloodstream. Once in the blood, HIV “hijacks” certain cells. One of the cells that it hijacks is the CD4 T-cell, also known as the CD4 cell, helper/inducer T-cell, or T4-cell (Kaufman, 2011) (see Chapter 19). This cell directs immune system defenses and regulates the activity of all immune system cells. If HIV successfully enters a CD4 T-cell, it can then create more virus particles.



Virus-host interactions are needed for disease development. When a person is infected with HIV, the virus randomly “bumps” into many cells. The docking proteins on the outside of the virus try to find special receptors on a host cell that will allow the virus to bind and then enter the cell. The CD4+ T-cell has receptors on its surface known as CD4, CCR5, and CXCR4 (Fig. 21-2). Proteins on the HIV particle surface, known as gp120 and gp41, recognize these receptors on the CD4+ T-cell. For the virus to enter this cell, both the gp120 and the gp41 must bind to the receptors. The gp120 first binds to the primary CD4 receptor, which changes its shape and allows the gp41 to bind to one of the co-receptors (either the CCR5 receptor or the CXCR4 receptor). This attachment allows the virus to then enter the CD4+ T-cell (Fig. 21-3). Viral binding to the CD4 receptor and to either of the co-receptors is needed to enter the cell. (The new drug class known as entry inhibitors works here to block the receptor and prevent the interaction needed for entry of HIV into the CD4+ T-cell.)




Viruses, like human cells, have genetic material. After entering a host cell, HIV must get its genetic material into the host cell’s DNA. HIV belongs to a family of viruses called retroviruses. The genetic material of the human cell is double-stranded DNA (ds-DNA). The genetic material of HIV is single-stranded ribonucleic acid (RNA) (ss-RNA). To infect and take over a human cell, the genetic material must be the same. HIV overcomes this problem by bringing along an enzyme at the time of infection, reverse transcriptase (RT). RT takes HIV’s ss-RNA and converts it into ds-DNA, which makes the viral genetic material the same as human DNA. (The drug classes known as nucleoside analog reverse transcriptase inhibitors [NRTIs] and non-nucleoside reverse transcriptase inhibitors [NNRTIs] work here to inhibit HIV reverse transcriptase.) Then HIV must get its DNA into the nucleus of the CD4+ T-cell and place it within the human DNA. HIV also brings an enzyme called integrase. This enzyme allows the viral ds-DNA to be inserted into the host ds-DNA, which completes the infection of the CD4+ T-cell. (The drug class known as integrase inhibitors works here to prevent viral DNA from integrating into the cell’s normal human DNA.)


HIV particles are made within the infected CD4+ T-cell, using all the metabolic machinery of the host. The new virus particle is made in the form of one long protein strand. The strand is clipped, using chemical enzyme scissors called HIV protease, into several small functional pieces. These pieces are formed into a new finished viral particle. (The drug class known as protease inhibitors works here to inhibit HIV protease.) Once the new virus particle is finished, it fuses with the infected cell’s membrane and then buds off in search of another CD4+ T-cell to infect (Fig. 21-4).



Effects of HIV infection are related to the new genetic instructions that now direct CD4+ T-cells to change their role in immune system defenses. The new role is to be an “HIV factory.” The immune system is made weaker by removing some CD4+ T-cells from circulation, and the most important cell in the immune system becomes an HIV factory. Up to 10 billion virus particles are made daily. In early HIV infection, the immune system can still attack and destroy most of the newly created virus particles. With time, however, the number of HIV particles overwhelms the immune system. Gradually, CD4+ T-cell counts fall, viral numbers (viral load) rise, and without treatment, the patient eventually dies of opportunistic infections or cancer.


Everyone who has AIDS has HIV infection; however, not everyone who has HIV infection has AIDS. The distinction rests with the number of CD4+ T-cells the patient has and whether any opportunistic infections have occurred. A healthy adult usually has at least 800 to 1000 of these cells per cubic millimeter (mm3) of blood. The number of CD4+ T-cells is reduced in the person with HIV disease.


About 50% to 90% of people who are first infected with HIV develop an acute infection within 4 weeks. Manifestations of this acute HIV infection can be fever, night sweats, chills, headache, and muscle aches. All of these problems can be caused by exposure to almost any virus (e.g., influenza)—not just to HIV. Many people with this acute HIV infection also have a rash and a sore throat, which is often confused with mononucleosis and viral meningitis. With time, these symptoms cease and the person feels well again. Actually, a “war is going on” in the body between HIV and the immune system.


As time passes, with more CD4+ T-cells infected and taken out of service, this cell count drops to below normal levels and those that remain may not function normally. Poor CD4+ T-cell function as a result of HIV infection leads to these immune system abnormalities:



As the CD4+ T-cell level drops, the patient is at risk for bacterial, fungal, and viral infections, as well as opportunistic cancers. Opportunistic infections are those caused by organisms that are present as part of the body’s normal environment and are kept in check by normal immune function. They occur because of the profound immunosuppression in the person with AIDS. These infections may result from a newly acquired infection or reactivation of an old infection.


A diagnosis of AIDS requires that the person be HIV positive and have either a CD4+ T-cell count of less than 200 cells/mm3 or an opportunistic infection. Once AIDS is diagnosed, even if the patient’s cell count goes higher than 200 cells/mm3 or the infection is successfully treated, the AIDS diagnosis remains and the patient never reverts to being just HIV positive.



HIV Classification

The Centers for Disease Control and Prevention (CDC), in a 1993 definition, classified HIV infection by correlating clinical conditions with three ranges of CD4+ T-cell counts. This classification was replaced in 2008 by defining four stages of the disease. In this new definition, laboratory confirmation of HIV infection (by enzyme-linked immunosorbent assay [ELISA] and Western blot analysis) plus CD4+ T-lymphocyte count or percentage and the presence or absence of the 26 AIDS-defining conditions (Table 21-1) determine the classification (CDC, 2008). The person with HIV infection can transmit the virus to others at all stages of disease, but the recently infected person with a high viral load and those at end stage without drug therapy can be particularly infectious.



TABLE 21-1 CENTERS FOR DISEASE CONTROL AND PREVENTION CLASSIFICATION OF AIDS-DEFINING CONDITIONS IN ADULTS







Centers for Disease Control and Prevention. (2008). Recommendations and reports: Appendix A—AIDS-defining conditions. Morbidity and Mortality Weekly Report, 57(RR-10), 9.



HIV Progression

The time from the beginning of HIV infection to development of AIDS ranges from months to years. The range depends on how HIV was acquired, personal factors, and interventions. For people who have been transfused with HIV-contaminated blood, for example, AIDS often develops quickly. For those who become HIV positive as a result of a single sexual encounter, the period is much longer before progression to AIDS. Other personal factors that may influence progression to AIDS include frequency of re-exposure to HIV, presence of other sexually transmitted diseases (STDs), nutritional status, and stress.




Incidence/Prevalence


Since the beginning of the epidemic in the United States, more than 1.2 million cases of HIV/AIDS have been diagnosed, and more than 617,025 people have died of AIDS. Currently, more than 600,000 people in the United States are living with HIV/AIDS (CDC, 2011). This number is less than the total number of people in the United States estimated to be infected with HIV (1.1 million to 1.8 million). Worldwide, about 40 to 60 million people are currently infected with HIV, at least 30 million deaths from AIDS have occurred, and 33 million people are living with AIDS (WHO, 2010).


AIDS hits hardest among people between 21 and 44 years of age. The loss of productivity and wage-earning power among this group devastates the patient and strains the insurance and health care industry.


Most AIDS cases in North America occur among men who have had sex with other men (MSM) (53%) or individuals of either gender who have used injection drugs (16%) (CDC, 2011). The changing demographics of the infection indicate that the perception that HIV/AIDS is only a problem for homosexual white men is false (Kirton, 2011).




Considerations for Older Adults


Infection with HIV can occur at any age. Assess the older patient for risk behaviors, including a sexual and drug use history (Tangredi et al., 2008). Age-related decline in immune function increases the likelihood that the older adult will develop the infection after an HIV exposure. In the older woman, thinning of vaginal tissue as a result of decreased estrogen may increase susceptibility to all sexually transmitted diseases, including HIV infection. Cognitive deficits appear to occur earlier in the older adult with HIV (Vance, 2010).



AIDS is a disease with a high mortality rate. The fatality rate is at least 60% for adults and, to date, there is no cure (WHO, 2010). Thus a major focus for health care in North America and worldwide is prevention of HIV infection. For those infected with HIV, drug therapy slows disease progression and, to be effective, it must be taken as prescribed for the rest of the patient’s life.



Health Promotion and Maintenance


HIV has been found in most body fluids of infected patients, including blood, semen, vaginal secretions, breast milk, amniotic fluid, urine, feces, saliva, tears, cerebrospinal fluid, lymph nodes, cervical cells, corneal tissue, and brain tissue. The fluids with the highest concentrations of HIV are the semen and the blood. It is also present in vaginal fluids and breast milk. Thus HIV is transmitted most often in these three ways:



Teach everyone about the transmission routes and ways to reduce their exposure (discussed next). Also stress that HIV is not transmitted by casual contact in the home, school, or workplace. Sharing household utensils, towels and linens, and toilet facilities does not transmit HIV. In addition, HIV is not spread by mosquitoes or other insects.




Sexual Transmission


The CDC describes the ABC safer sex methods as A, abstinence; B, be faithful; and C, condoms (CDC, 2009b). Abstinence and mutually monogamous sex with a noninfected partner are the only absolutely safe methods of preventing HIV infection from sexual contact. Many forms of sexual expression can spread HIV infection if one partner is infected. The risk for becoming infected from a partner who is HIV positive is always present, although some sexual practices are more risky than others. The virus concentrates most heavily in blood and seminal fluid, although it is also present in vaginal secretions. Thus risk differs by gender, sexual act, and the viral load of the infected partner.


Gender affects HIV transmission. HIV is most easily transmitted when infected body fluids come into contact with mucous membranes or nonintact skin. The vagina has much more mucous membrane than does the penis. Thus HIV, like all other sexually transmitted diseases (STDs), is more easily transmitted from infected male to uninfected female than vice versa. Teach women the importance of always either using a vaginal or dental dam or female condom, or having their male partners use a condom.


Sexual acts or practices that permit infected seminal fluid to come into contact with mucous membranes or nonintact skin are the most risky for sexual transmission of HIV. The practice with the highest risk is anal intercourse. In anal intercourse, the risk increases when the penis and seminal fluid of an infected person come into contact with the mucous membranes of the uninfected partner’s rectum. Anal intercourse in which the semen depositor (inserting or active partner) is infected is a very risky sexual practice regardless of whether the semen receiver (receiving partner) is male or female. Anal intercourse not only allows seminal fluid to make contact with the mucous membranes of the rectum but also tears the mucous membranes, making infection more likely. Teach patients who engage in anal intercourse that the safer sex practice is for the semen depositor to wear a condom during this act.


Viral load, or the amount of virus present in blood and other body fluids, affects transmission. The higher the blood level of HIV (viremia), the greater the risk for sexual and perinatal transmission. Current highly active antiretroviral therapy (HAART) has caused the viral load of some infected patients to drop below detectable levels. Although there is less virus in seminal or vaginal fluids of people receiving HAART, the risk for transmission still exists (Kirton, 2011).


Safer sex practices are those that reduce the risk for nonintact skin or mucous membranes coming in contact with infected body fluids and blood. Teach everyone the importance of consistently using these safer sex practices:




A promising area of research for prevention of sexual transmission is the use of vaginal gels that contain an antiretroviral agent (tenofovir or raltegravir). Early results indicate that if the gel is used before and after intercourse, new infections among women can be reduced by as much as 50% (Abdool Karim et al., 2010).


For those who believe they have been exposed to HIV as a result of sexual relations or other types of nonoccupational exposure, the CDC has guidelines for postexposure prophylaxis. The length and type of prophylaxis therapy depend on the nature of the exposure (Chart 21-2).



Chart 21-2 Patient and Family Education


Preparing for Self-Management: Nonoccupational Postexposure Prophylaxis (nPEP) to HIV






















Recommendations for nPEP with a substantial risk for HIV exposure is a 28-day course of the preferred regimen of HAART*
NNRTI-based Efavirenz plus either lamivudine or emtricitabine plus either zidovudine or tenofovir
or
PI-based Lopinavir/ritonavir plus either lamivudine or emtricitabine plus zidovudine
A substantial risk is exposure of any of these:




HAART, Highly active antiretroviral therapy; NNRTI, non-nucleoside reverse transcriptase inhibitor; PI, protease inhibitor.


* Either when a substantial risk has occurred and more than 72 hours has passed since the exposure or when the exposure is considered to be a negligible risk, nPEP is not recommended.


When a substantial risk has occurred and less than 72 hours has passed since the exposure but the HIV-infection status of the source person is not known, nPEP is determined on a case-by-case basis.


Data from Centers for Disease Control and Prevention. (2005). Antiretroviral postexposure prophylaxis after sexual, injection-drug use, or other nonoccupational exposure to HIV in the United States. Morbidity and Mortality Weekly Report, 54(RR-2), 1-27.



Parenteral Transmission


Preventive practices to reduce transmission among injection drug users (IDUs) include the use of proper cleaning of “works” (needles, syringes, other drug paraphernalia). Instruct IDUs to clean a used needle and syringe by first filling and flushing them with clear water. Next, the syringe should be filled with ordinary household bleach. The bleach-filled syringe should be shaken for 30 to 60 seconds. Advise IDUs to carry a small container with this solution whenever sharing needles. Some communities have a needle exchange program in which needles and syringes are used only once and are then exchanged for clean ones.


The risk for AIDS transmission through blood and blood products has been reduced to a national average of 0.02%. Several measures are used to protect the nation’s blood supply. All donated blood in North America is screened for the HIV antibody, and blood that is positive for HIV antibodies is discarded. Because of the time lag in antibody production (seroconversion) after exposure to HIV, infected blood can test negative for HIV antibodies. False-negative and false-positive results also can occur for other reasons. Inform patients that there is a small but real possibility of HIV transmission through blood and blood products. As a result, methods for reducing transfusion-related infections have included less reliance on standard transfusion therapy through more stringent criteria for transfusion, the use of growth factors to promote more rapid blood production in the patient, and an increase in autologous transfusion in which the patient donates his or her own blood to be transfused back at a later time.




Transmission and Health Care Workers


Needle stick or “sharps” injuries are the main means of occupation-related HIV infection for health care workers. In addition, health care workers can be infected through exposure of nonintact skin and mucous membranes to blood and body fluids. Because of the time lag between the time of infection with HIV and the production of serum antibodies (seroconversion), infected people can test negative for HIV and still transmit the virus. The best prevention for health care providers is the consistent use of Standard Precautions for all patients as recommended by the CDC and required by The Joint Commission (TJC) (see Chapter 25). Chart 21-3 lists the recommended actions for prevention of HIV infection after a needle stick or other occupational exposure (postexposure prophylaxis [PEP]). When the source patient is known to be HIV negative, PEP is not recommended.



Chart 21-3


Data from Centers for Disease Control and Prevention. (2005). Updated Public Health Service guidelines for the management of health-care worker exposure to HIV and recommendations for postexposure prophylaxis. Morbidity and Mortality Weekly Report, 54(RR-9), 1-22.


Best Practice for Patient Safety & Quality Care: Postexposure Prophylaxis (PEP) for Occupational HIV Exposure*

















BASIC PEP EXPANDED PEP







* When PEP therapy is instituted, the recommended course is 28 days.


Basic PEP = Two drugs: (zidovudine plus lamivudine or emtricitabine); or (stavudine plus lamivudine or emtricitabine); or (tenofovir plus lamivudine or emtricitabine).


Expanded PEP = Three or more drugs: (zidovudine plus lamivudine or emtricitabine plus lopinavir/ritonavir); or (stavudine plus lamivudine or emtricitabine plus lopinavir/ritonavir); or (tenofovir plus lamivudine or emtricitabine plus lopinavir/ritonavir).


The public may be concerned about HIV transmission by health care workers. Health care workers should wear gloves when in contact with patients’ mucous membranes or nonintact skin. Infected workers with weeping dermatitis or open lesions should not perform direct care. The CDC guidelines for preventing HIV transmission by health care workers during exposure-prone invasive procedures are listed in Chart 21-4. These include any procedure in which there is a risk for broken skin injury to the health care worker and the worker’s blood is likely to make contact with the patient’s body cavity, subcutaneous tissues, or mucous membranes. The purpose of these guidelines is to reduce the risk for HIV transmission to patients.





Testing


Testing for HIV antibodies or other features of the virus is complex, requiring interpretation, counseling, and confidentiality. Testing plays a role in prevention because tests are a way of diagnosing HIV infection before immune changes or symptoms develop. A primary health care focus for testing is to teach those who test positive to modify their behaviors to prevent transmission to others. Therefore all sexually active people should know their HIV status. Chart 21-5 lists additional conditions for which HIV antibody testing is advised.



Pretest and post-test counseling must be performed by personnel trained in HIV issues. These counselors may be nurses, physicians, social workers, health educators, or even lay educators who have specialized training. Counseling helps the patient make an informed decision about testing and provides an opportunity to teach risk-reduction behaviors. Post-test counseling is needed to interpret the results, discuss risk reduction, and provide psychological support and health promotion information for the patient with a positive test result. People who test positive should also be counseled on how to inform sexual partners and those with whom they have shared needles. Testing methods, their accuracy, and indications are presented on pp. 368-369 in the Laboratory Assessment section.




History


Ask specifically about age, gender, occupation, and where the person lives. Thoroughly assess the current illness, including its nature, when it started, the severity of symptoms, associated problems, and any interventions to date. Ask the patient about when the HIV infection was diagnosed and what clinical symptoms led to that diagnosis. Ask him or her to give a chronologic history of infections and clinical problems since the diagnosis. Assess the patient’s health history, including whether he or she received a blood transfusion between 1978 and 1985 in the United States (before routine blood testing for HIV contamination). Blood testing for HIV contamination is not consistently performed in all parts of the world and is a source of infection for immigrants. Ask the immigrant patient about his or her history of transfusion therapy before coming to the United States.


Ask the patient about sexual practices, sexually transmitted diseases (STDs), and any major infectious diseases, including tuberculosis and hepatitis. If the patient has hemophilia, ask about treatment with clotting factors. Determine whether the patient has engaged in past or present injection drug use, including needle exposure and needle sharing. Assess the patient’s level of knowledge regarding the diagnosis, symptom management, diagnostic tests, treatments, community resources, and modes of HIV transmission. Also assess his or her understanding and use of safer sex practices. If knowledge deficits are found, provide the appropriate patient teaching.


Jul 18, 2016 | Posted by in NURSING | Comments Off on Care of Patients with HIV Disease and Other Immune Deficiencies

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