AIDS

INCIDENCE (IN U.S.):
• 27.1 cases/100,000 persons
• Varies widely by location
• 85% of cases in large cities
PREVALENCE (IN U.S.): 62 cases/100,000 persons
PREDOMINANT SEX: Males 84%, females 16% (through 1998)
40% of newly reported U.S. cases in 1999 were in women.
PREDOMINANT AGE: 80% between ages 20 and 40 yr
PEAK INCIDENCE: See above
GENETICS:
• Familial disposition: no clear genetic predisposition
• Congenital infection:
1.Transmittable from an infected mother to the fetus in utero in as many as 30% of pregnancies.
2.No specific congenital malformations associated with infection; low birth weight and spontaneous abortion are possible.
• Neonatal infection: transmission possible to the neonate intrapartum or postpartum through breast-feeding

• Nonspecific findings: fever, weight loss, anorexia
• Specific syndromes:

1.Seen in association with opportunistic infection and malignancies, so-called indicator diseases
2.Most common:

• Caused by infection with human immunodeficiency virus, type 1 (HIV-1)
• Transmitted by heterosexual or male homosexual contact, needle-sharing (during IV drug use), transfusion of contaminated blood or blood products, and from infected mother to fetus or neonate as described above

DIFFERENTIAL DIAGNOSIS
• Other wasting illnesses mimicking the nonspecific features of AIDS:

1.TB
2.Neoplasms
3.Disseminated fungal infection
4.Malabsorption syndromes
5.Depression
• Other disorders associated with dementia or demyelination producing encephalopathy, myelopathy, or neuropathy
WORKUP
Prompt evaluation of respiratory, CNS, GI complaints
LABORATORY TESTS
• HIV antibody testing
• T-lymphocyte subset analysis: performed to determine the degree of immunodeficiency
• Viral load assay: to plan long-term antiviral therapy consider genotype or phenotype sensitivity testing for patients failing therapy
• CSF examination: for meningitis
• Serologic tests for syphilis, hepatitis B, hepatitis C, and toxoplasmosis
IMAGING STUDIES
• Cerebral CT for encephalopathy or focal CNS complications (e.g., toxoplasmosis, lymphoma)
• Pulmonary gallium scanning to aid in the diagnosis of a Pneumocystis carinii pneumonia

NONPHARMACOLOGIC THERAPY
• Maintain adequate caloric intake
• Encourage good oral hygiene, regular dental care
ACUTE GENERAL Rx
Acute management of opportunistic infections and malignancies is reviewed elsewhere in this text under specific AIDS-related disorders.
CHRONIC Rx
For all HIV-infected patients, particularly those meeting the case definition of AIDS:
• Preventive therapy for Pneumocystis carinii pneumonia and TB (see specific chapters elsewhere in this text). With the advent of modern antiretroviral therapy many patients have experienced substantial restoration of cellular immune function. It has become clear that preventive therapy for Pneumocystis carinii and Mycobacterium avium complex as well as suppressive therapy for cytomegaloviral and cryptococcal infection can often be safely withdrawn if the CD4 cell count rises above 200 for at least 6 months.
• Antiretroviral therapy employing combinations of nucleoside derivative agents: zidovudine (AZT), didanosine (DDI), zalcitabine (DDC), lamivudine (3TC), stavudine (D4T), abacavir in addition to protease inhibitors (saquinavir, ritonavir, indinavir, nelfinavir, agenerase, ritonavir/lopinavir) nonnucleoside reverse transcriptase inhibitors (nevirapine, delavirdine, efavirenz) or the nucleotide agent tenofovir according to current recommendations based on clinical stage and viral load studies.
• An approach to evaluating chronic diarrhea in patients with HIV infection, the approach to the acutely ill HIV-infected patient, and the evaluation of respiratory complaints is described in Section III. Approach to a patient with a suspected CNS lesion is also described in Section III.
• Genotypic resistance testing should be strongly considered for any patient failing antiretroviral therapy.

All patients with AIDS: to a physician knowledgeable and experienced in the management of the disease and its complications

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Isada CM: New developments in long-term treatment of HIV: the honeymoon is over, Cleve Clin J Med 68(9):804, 2001.

Kaplan JE et al: Epidemiology of human immunodeficiency virus–associated opportunistic infections in the United States in the era of highly active antiretroviral therapy, Clin Infect Dis 30(suppl 1):S5, 2000.

Kaplan JE et al: Discontinuing prophylaxis against recurrent opportunistic infections in HIV-infected persons: a victory in the era of HAART, Ann Intern Med 137:285, 2002.

Kirk O et al: Safe interruption of maintenance therapy against previous infection with four common HIV-associated opportunistic pathogens during potent antiretroviral therapy, Ann Intern Med 137:239, 2002.

Palmer S et al: Tenofovir, adefovir andzidovudine susceptibilities of primary human immunodeficiency virus type 1 isolates with non-B subtypes or nucleoside resistance, AIDSRes Hum Retroviruses 17(12):1167, 2001.

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Richman DD: HIV chemotherapy, Nature 410:995, 2001.