After primary exposure to the virus, there is a burst of viral replication during which the virus is disseminated into lymphoid tissue. The immune system responds and in most patients can contain viral replication initially. A prolonged elevation of the amount of virus circulating in the bloodstream (the viral load or viral burden) is highly correlated with the rate of disease progression. This interval before the development of symptoms, termed “disease-free survival time,” is quite variable from one person to the next. It is likely that both viral replication and host defenses are involved in the rate of progression of the disease (Fauci, 1996). With the current use of multidrug therapy, viral replication may remain unmeasurable for more than 10 years. However, what actually triggers the eventual decline of the immune system and resultant increase in viremia is still unclear.

The virus enters the body as a direct injection (eg, blood transfusion or intravenous drug use) or through sexual contact via a mucosal surface. Concurrent infections, such as a sexually transmitted disease or tuberculosis (TB), increase the rate of transmission. Virus is produced at the rate of 10 billion virions per day, with infected cells having a life span of 2.2 days. The life cycle of the virus is 1.2 days, and it is this rapid growth, resulting in a high level of CD4 cell destruction, that has changed the way the disease is managed clinically (Perelson et al, 1996).

Lymphoid tissue is the general reservoir for the virus. All immune cell types are affected, although the CD4 cells and monocytes are the main targets. Although the use of protease inhibitors usually decreases the amount of circulating virus, a simultaneous increase in CD4 cells does not always result. This may be because HIV not only causes direct cell destruction but also may have a role in producing programmed cell death (apoptosis).

The immune system is regulated by cytokines, soluble proteins that make up a complex messenger network to control gene activation and the expression of cell surface receptors. There are cytokines that stimulate the production of HIV and
those that suppress replication. The same cytokine may produce opposite results at different times in the life cycle of cells. The complexity of the immune system and of HIV itself makes the development of useful clinical therapies a very difficult task.

Within the context of the HIV/AIDS epidemic is the provider’s obligation to understand how culture and subsequent belief systems affect health promotion. Often referred to as “special populations” issues, HIV has invaded every population and culture. Understanding diversity has a critical impact on a provider’s ability to function effectively and treat appropriately. The effective outcome may be to prevent transmission, provide treatment or access to clinical trials, or to identify sources of support in special population communities. Table 41-1 is a brief summary of special populations, listing definitions, issues, and options for intervention. Specific referral sources may be found in the resources list toward the end of this chapter.

HIV infection has crossed socioeconomic lines in ways that are uncharacteristic of other infectious diseases. Initially considered a disease of gay white males, HIV has infected and affected the wealthy and famous, the middle class, and the extremely disadvantaged. Epidemiologically in the United States, financial and social issues have had an impact on disease transmission, treatment, and survival.

HIV infection is now found along all racial, ethnic, gender, age, and economic lines. Particularly in urban areas, HIV infection is concentrated in people of minority groups in inverse proportion to their numbers in the population (CDC, 1994a; Byerly & Deardorff, 1994). Within racial and ethnic groups, women and adolescents are becoming infected at a faster rate than ever before.

Although injection drug use is practiced across socioeconomic lines, it is concentrated in areas where racial and ethnic minorities and economic disadvantage exist. These are the same neighborhoods where a lack of money and infrastructure makes it extremely difficult to increase HIV awareness and prevent transmission. Prevention strategies such as free needle exchanges or distribution of condoms have been opposed in some communities.

From 1990 to 1996, the incidence of AIDS rose three times faster in women than in men. Women now account for more than 92,200 (15%) of the cumulative AIDS cases in the United States (CDC, 1997b). For the first time, heterosexual sex rather than injection drug use is the leading cause of HIV transmission in women. African American and Hispanic women have consistently accounted for nearly 75% of AIDS cases, and in 1996 African American women represented more than half the new cases of AIDS (CDC, 1997b). As is the case for men, AIDS is the second leading cause of death for women ages 25 to 44. The prevalence of HIV infection among childbearing women nationwide is 1.6 per 1000, accounting for approximately 6500 births (Gwinn et al, 1991; Gwinn & Wortley, 1996).

Because the rate of HIV infection is disproportionately high among impoverished minority women, the social context of their lives is central to their experience and concerns about HIV. The primary care provider cannot separate the issues of poverty, minority status, substance use, gender, domestic violence, and isolation from medical care. Health care use is often sporadic and crisis-oriented as the competing concerns of housing, food, and health care for family members mesh (Anastasio et al, 1995; Hellinger, 1993; Casey et al, 1996; Ragsdale et al, 1995; Fox, 1995).

Although the natural history of HIV disease appears to be the same for both women and men, there tend to be some differences in clinical manifestations. Women appear to have a greater incidence of candidal esophagitis, a greater incidence of mucocutaneous herpes simplex ulcerations, and a low incidence of Kaposi sarcoma.

HIV may affect contraception as well as gynecologic problems (their frequency, presentation, natural history, and response to treatment). The primary care provider must be aware of the impact of HIV on these issues, for it can enable the identification of women at risk for HIV and can improve care to HIV-positive women (Table 41-2).

Studies in the United States show that HIV has not been demonstrated to affect the course or outcome of pregnancy; likewise, pregnancy does not affect HIV progression in woman (U.S. Public Health Service, 1997). Infection from the mother during pregnancy accounts for approximately 90% of cases of pediatric AIDS in the United States (CDC, 1994b). The use of zidovudine during pregnancy and labor and at delivery reduces the risk of HIV transmission by two thirds (CDC, 1994b). Before discussing a chemoprophylaxis regimen with the patient, the primary care provider should contact the CDC for the most current recommendation, as well as an obstetrician who specializes in HIV or an HIV subspecialist. Then the provider should discuss with and offer the patient the most current antepartum, intrapartum, and postpartum regimen (Casey et al., 1996; Landers, 1997).

In 1995, the U.S. Public Health Service (USPHS) issued recommendations for HIV counseling and voluntary testing of all pregnant women (CDC, 1995b). In addition, some states require testing of all newborns.

As the AIDS epidemic expands, an increasing number of health care workers will encounter patients infected with HIV. The threat of occupational exposure to HIV is real but small. The average risk for HIV infection from all types of percutaneous exposures to HIV-infected blood is 0.3%, although it may be greater when the exposure involves a larger blood volume or a higher HIV titer in blood (MMWR, 1996).

Currently, there are 52 documented cases of HIV infection in health care workers as a result of occupational exposure (CDC, 1996). The Occupational Health and Safety Administration (OSHA), in an effort to minimize such exposures, developed the Bloodborne Pathogen Standard (Rules and Regulations, 1991). These government regulations require employers to protect employees by using universal precautions, having written exposure control plans, and adhering to the postexposure prophylaxis recommendations of the USPHS.

Postexposure prophylaxis with zidovudine (AZT) has been associated with a decrease of approximately 79% in the risk for HIV seroconversion after percutaneous exposure to HIV-infected blood (MMWR, 1996). Subsequently, the USPHS revised its recommendations to include lamivudine (3TC) and protease inhibitors, indinavir and/or nelfinavir (Table 41-3). In addition to chemoprophylaxis, the recommendations include the following:

Prevention of exposure remains the key. Adherence to universal precautions and the use of needleless and protected needle intravenous systems can reduce the number of exposures in the workplace (Kelen et al, 1991; Ippolito et al, 1997).

Early diagnosis of HIV with appropriate treatment can offer a patient many years of productive life. Making the diagnosis requires primary care providers to consider HIV screening for most patients and to suspect HIV infection in many situations (Table 41-4). With the spread of the epidemic into lower-risk populations, it is prudent to offer HIV screening to all sexually active patients. In addition, it is good practice to offer testing to any patient with a history of chemical dependency because of the possibility of unprotected sex while intoxicated. The offer of testing provides an excellent opportunity to raise awareness of HIV among patients and to discuss the need for protection.

Risky behaviors can also be assessed during the history. Ownby, Ferri, and Vlahov (in Casey et al, 1996) stratified risky behavior as follows:

The most appropriate teaching strategy is one chosen by a provider who is aware of the patient’s life, including cultural and socioeconomic factors. In addition, providers need to explore their own comfort with teaching risk-reduction behaviors. This is achieved by confronting their fears and prejudices as well as practicing such teaching.

The standard physical exam includes serial assessments of weight and nutrition. A meticulous exam of the scalp and skin is essential (Table 41-5). The provider may first suspect HIV infection on finding specific conditions in the mouth. Oral hairy leukoplakia is a benign thickening of the mucosa in a corrugated pattern, often on the lateral surfaces of the tongue. Thrush (candidiasis) may present as erythema or more commonly as white, nonadherent plaques on the tongue, palate, buccal surfaces, or pharynx. The infection responds well to local or mild systemic antifungals. With more advanced immunosuppression, the infection involves the esophagus and may cause difficulty in swallowing solids. Severe, recurrent, or persistent herpes labialis is also common and responds to acyclovir and related drugs. Advanced gingivitis and periodontitis are also common and may interfere greatly with nutrition. Extensive treatment by a dentist is usually necessary. Kaposi sarcoma and bacillary angiomatosis can also present as oral lesions.

A funduscopic exam, a survey of lymph nodes, a neurologic exam (focusing on possible cognitive deficits and peripheral neuropathies), a routine cardiopulmonary exam, and a careful genital/rectal examination for coexisting diseases must also be done during the initial assessment, and any time there is a suspicion that one of these organ systems may have become involved.

Although it is beyond the scope of this chapter to discuss all opportunistic infections in detail, the primary care provider should be familiar with the identification and significance of certain infections. The prevention of opportunistic infections is well defined. The guiding principle is simple: primary prophylaxis, when possible, is best (See Table 41-9). Currently, the USPHS and the Infectious Disease Society of America (CDC, 1997c) strongly recommend primary prophylaxis as a standard of care for Pneumocystis carinii pneumonia (PCP), Mycobacterium avium complex, Toxoplasma gondii infection, and TB. In addition, prophylaxis for Streptococcus pneumoniae and varicella is warranted.