Acquired Immunodeficiency Syndrome
- Philip A. Chan, M.D., M.S.
Basic Information
Definition
Acquired immunodeficiency syndrome (AIDS) is a disorder caused by infection with the human immunodeficiency virus (HIV) and marked by progressive deterioration of the cellular immune system, leading to secondary (opportunistic) infections and/or malignancies.
Synonyms
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AIDS
ICD-10CM CODES | |
B20 | Human immunodeficiency virus [HIV] disease |
Epidemiology & Demographics
Incidence (In U.S.)
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The estimated number of persons diagnosed with AIDS in the U.S. is approximately 18,000/year.
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There is a disproportionate number of new AIDS cases among Black/African Americans and Latino/Hispanic Americans compared with White Americans.
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The majority of all new AIDS diagnoses are among gay, bisexual, or other men who have sex with men (MSM).
Prevalence (In U.S.)
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The cumulative number of AIDS diagnoses in the U.S. exceeds 1.2 million.
Predominant Sex
Men constitute approximately 75% of incident AIDS diagnoses in the U.S.; more than half of AIDS diagnoses occur in MSM.
Predominant Age
The predominant age group diagnosed with AIDS is 25 to 54 years of age.
Peak Incidence
Ages 30 to 34 years
Genetics
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Familial disposition: Although there is no proven genetic predisposition, individuals with deletions in the CCR5 gene are immune from HIV infection with macrophage tropic virus (the predominant virus in sexual transmission) and may progress to AIDS more slowly.
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Congenital infection:
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HIV is transmittable from an infected mother to the fetus in utero in as many as 30% of pregnancies.
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No specific congenital malformations associated with infection; low birth weight and spontaneous abortion are possible.
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Physical Findings & Clinical Presentation
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Nonspecific findings: fever, weight loss, anorexia.
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Specific syndromes:
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Seen in association with opportunistic infections and malignancies, so-called indicator diseases; these include:
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a.
Opportunistic infections:
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Disseminated strongyloidiasis
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2.
Disseminated toxoplasmosis, cryptococcosis, histoplasmosis, cytomegalovirus (CMV), herpes simplex, or mycobacterial disease
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Candida esophagitis or bronchopulmonary disease
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4.
Chronic Cryptosporidia spp. diarrhea
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Pneumocystis jiroveci pneumonia (PJP)
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Extensive pulmonary and extra-pulmonary tuberculosis
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Recurrent bacterial pneumonia
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Progressive multifocal leukoencephalopathy (PML)
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b.
AIDS-related neoplasms:
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Kaposi’s sarcoma
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Primary brain lymphoma
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Invasive cervical carcinoma
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High-grade B cell non-Hodgkin’s lymphoma, Burkitt’s lymphoma, undifferentiated non-Hodgkin’s lymphoma, or immunoblastic lymphoma
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Most common:
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Respiratory infections (Pneumocystis jiroveci [formerly known as Pneumocystis carinii] pneumonia, TB, bacterial pneumonia, fungal infection)
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CNS infections (toxoplasmosis, TB)
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GI (cryptosporidiosis, isosporiasis, CMV); Sections II and III describe organisms associated with diarrhea in patients with AIDS
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Eye infections (CMV, toxoplasmosis)
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Kaposi’s sarcoma (cutaneous or visceral) or lymphoma (nodal or extranodal)
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Possibly asymptomatic.
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Diagnosis of AIDS if the CD4 cell count is <200 or <14% of total lymphocyte in the presence of proven HIV infection, even in the absence of other infections.
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The various manifestations of HIV infection are described in Section II.
Etiology
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Caused by infection with HIV-1 or HIV-2 (less common).
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HIV is transmitted by sexual contact, needle-sharing (during IV drug use), transfusion of contaminated blood or blood products, and from infected mother to fetus or neonate as described previously.
Diagnosis
Differential Diagnosis
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Other wasting illnesses mimicking the nonspecific features of AIDS:
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TB
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Neoplasms
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Disseminated fungal infection
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Malabsorption syndromes
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Depression
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Other disorders associated with dementia or demyelination producing encephalopathy, myelopathy, or neuropathy.
Workup
Prompt evaluation of respiratory, CNS, and GI complaints
Laboratory Tests
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HIV antibody testing. See “Human Immunodeficiency Virus” topic for the 2014 revised surveillance case definition for HIV infection.
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T-lymphocyte subset analysis: performed to determine the degree of immunodeficiency (i.e., CD4 cell count).
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Viral load assay: to plan long-term antiviral therapy and to follow progression and success of treatment (i.e., HIV RNA PCR).
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CSF examination: for meningitis (if indicated).
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Serologic tests for syphilis, hepatitis B, hepatitis C, and toxoplasmosis.
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Testing for other sexually transmitted diseases, such as gonorrhea and chlamydia.
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Genotypic resistance testing: used to assess for primary resistance in naïve patients and secondary resistance in patients failing a regimen.
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Eye exam: to evaluate for CMV retinitis in patients with CD4 counts <50 cells/mm3.
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Cryptococcal antigen: part of the evaluation in AIDS patients with CD4 counts <100 cells/mm3 who have fever, diffuse pneumonia, or evidence of meningitis.
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Evaluation for infection with mycobacterium (TB or MAI) including PPD, sputum cultures, chest radiograph, and blood cultures for acid-fast bacteria, depending on clinical presentation.
Imaging Studies
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MRI or CT of head for encephalopathy or focal CNS complications (e.g., toxoplasmosis [Fig. E1], lymphoma).
Chest radiography or CT to aid in the diagnosis of Pneumocystis jiroveci (P. carinii) pneumonia, TB, or bacterial pneumonia.
Treatment
The most important aspect in management of AIDS due to HIV infection is the timely initiation of antiretroviral therapy (see section on HIV treatment).
Nonpharmacologic Therapy
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Maintain adequate caloric intake.
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Encourage good oral hygiene and regular dental care.
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Avoid high-risk behaviors that increase the risk of repeated exposure to HIV and other potential pathogens—use condoms, avoid sharing needles, etc.
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Update vaccines—particularly the pneumococcal and hepatitis A/B vaccine along with annual influenza vaccines.
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Avoid administration of any live attenuated vaccines that may be a risk to these immunocompromised patients (e.g., MMR, varicella). (See Section V for immunization schedules for HIV-infected children.)
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When feasible, avoid activities that might increase risk of exposure to opportunistic infections (e.g., cleaning out a cat litter box [toxoplasmosis], getting scratched by a cat [Bartonella infections], exposure to pet reptiles [salmonellosis], traveling to developing countries [cryptosporidiosis, tuberculosis], eating undercooked foods and drinking from unsafe water supplies, etc.).
Acute General Rx
Acute management of opportunistic infections is summarized in Table 1 and reviewed elsewhere in this text under specific AIDS-related disorders. For management of AIDS-related malignancies, please refer to the specific malignancy elsewhere in this text.
Opportunistic Infection | Preferred Therapy | Alternative Therapy | Other Comments |
PJP |
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For Moderate to Severe PJP:
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Indications for Adjunctive Corticosteroids:
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Toxoplasma gondii encephalitis | Treatment of Acute Infection:
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Treatment of Acute Infection:
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Mycobacterium tuberculosis disease (TB) |
Initial Phase (2 months, given daily, 5-7 times/week by DOT):
Continuation Phase:
Total Duration of Therapy (for drug-susceptible TB):
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Treatment for Drug-Resistant TB
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Disseminated MAC disease | At Least 2 Drugs as Initial Therapy with:
Duration:
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Third or Fourth Drug Options May Include:
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Bacterial respiratory diseases (with focus on pneumonia) | Empiric antibiotic therapy should be initiated promptly for patients presenting with clinical and radiographic evidence consistent with bacterial pneumonia. The recommendations listed are suggested empiric therapy. The regimen should be modified as needed once microbiologic results are available. |
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Empiric Outpatient Therapy:
Empiric Therapy for Non-ICU Hospitalized Patients:
Empiric Therapy for ICU Patients:
Empiric Therapy for Patients at Risk of Pseudomonas Pneumonia:
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Empiric Outpatient Therapy:
Empiric Therapy for Patients at Risk of Pseudomonas Pneumonia:
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Bacterial enteric infections Empiric therapy pending definitive diagnosis |
Empiric Therapy:
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Empiric Therapy:
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Salmonellosis | All HIV-infected patients with salmonellosis should be treated because of high risk of bacteremia. |
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Duration of Therapy:
For gastroenteritis with bacteremia:
Secondary Prophylaxis Should Be Considered for:
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Mucocutaneous candidiasis | For Oropharyngeal Candidiasis; Initial Episodes (for 7-14 days):
For Esophageal Candidiasis (for 14-21 days):
For Uncomplicated Vulvovaginal Candidiasis:
For Severe or Recurrent Vulvovaginal Candidiasis:
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For Oropharyngeal Candidiasis; Initial Episodes (for 7-14 days):
For Esophageal Candidiasis (for 14-21 days):
For Uncomplicated Vulvovaginal Candidiasis:
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If Decision Is to Use Suppressive Therapy:
Vulvovaginal Candidiasis:
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Cryptococcosis | Cryptococcal Meningitis
For Non-CNS, Extrapulmonary Cryptococcosis and Diffuse Pulmonary Disease:
Non-CNS Cryptococcosis with Mild to Moderate Symptoms and Focal Pulmonary Infiltrates:
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Cryptococcal Meningitis
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Histoplasmosis | Moderately Severe to Severe Disseminated Disease Induction Therapy (for at least 2 weeks or until clinically improved):
Less Severe Disseminated Disease
Meningitis
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Moderately Severe to Severe Disseminated Disease Induction Therapy (for at least 2 weeks or until clinically improved):
Meningitis
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Coccidioidomycosis | Clinically Mild Infections (e.g., focal pneumonia):
Severe, Nonmeningeal Infection (diffuse pulmonary infection or severely ill patients with extrathoracic, disseminated disease):
Meningeal Infections:
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Mild Infections (focal pneumonia) for patients who failed to respond to fluconazole or itraconazole:
Severe, Nonmeningeal Infection (diffuse pulmonary infection or severely ill patients with extrathoracic, disseminated disease):
Meningeal Infections:
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Aspergillosis, invasive | Preferred Therapy:
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Alternative Therapy:
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CMV disease | CMV Retinitis Induction Therapy for Immediate Sight-Threatening Lesions (adjacent to the optic nerve or fovea)
For Small Peripheral Lesions:
CMV Esophagitis or Colitis:
Well-Documented, Histologically Confirmed CMV Pneumonia:
CMV Neurologic Disease
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CMV Retinitis Induction Therapy:
CMV Esophagitis or Colitis:
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Treatment of IRU:
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HSV disease | Orolabial Lesions (for 5-10 days):
Initial or Recurrent Genital HSV (for 5-14 days):
Severe Mucocutaneous HSV:
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For Acyclovir-Resistant HSV
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VZV disease | Primary Varicella Infection (Chickenpox):
Herpes Zoster (Shingles) Acute Localized Dermatomal:
Extensive Cutaneous Lesion or Visceral Involvement:
Progressive Outer Retinal Necrosis:
Acute Retinal Necrosis:
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Primary Varicella Infection (Chickenpox):
Herpes Zoster (Shingles)
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Progressive multifocal leukoencephalopathy (JC virus infections) |
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None. |
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ART, antiretroviral therapy; ARV, antiretroviral; bid, twice a day; CD4, CD4 T lymphocyte cell; CFU, colony-forming unit; CMV, cytomegalovirus; CNS, central nervous system; CSF, cerebrospinal fluid; CYP3A4, cytochrome P-450 3A4; DOT, directly observed therapy; DS, double strength; EMB, ethambutol; G6PD, glucose-6-phosphate dehydrogenase; GI, gastrointestinal; HSV, herpes simplex virus; ICU, intensive care unit; IM, intramuscular; INH, isoniazid; IRIS, immune reconstitution inflammatory syndrome; IV, intravenous; LP, lumbar puncture; MAC, Mycobacterium avium complex; mm Hg, millimeters of mercury; NSAID, nonsteroidal anti-inflammatory drugs; PCP, Pneumocystis pneumonia; PI, protease inhibitor; PML, progressive multifocal leukoencephalopathy; PO, oral; PZA, pyrazinamide; qid, four times a day; RFB, rifabutin; RIF, rifampin; SS, single strength; tid, three times daily; tiw, three times weekly; TMP-SMX, trimethoprim-sulfamethoxazole; VZV, varicella zoster virus. Quality of Evidence for the Recommendation: I: One or more randomized trials with clinical outcomes and/or validated laboratory endpoints II: One or more well-designed, nonrandomized trials or observational cohort studies with long-term clinical outcomes III: Expert opinion |
Chronic Rx
For all HIV-infected patients, particularly those meeting the case definition of AIDS:
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Preventive therapy for Pneumocystis jiroveci pneumonia and Mycobacterium avium (see specific chapters elsewhere in this text). With the advent of modern antiretroviral therapy, many patients have experienced substantial restoration of cellular immune function. Preventive therapy for Pneumocystis jiroveci and Mycobacterium avium complex as well as suppressive therapy for CMV and cryptococcal infection can be safely stopped if the CD4 cell count rises above 200 for at least six months.
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Based on the Department of Health and Human Services (DHHS) Guidelines, active antiretroviral therapy (ART) should be started regardless of CD4 cell count. Individuals with CD4 cell counts <350 and especially CD4 cell counts <200 should be strongly encouraged to start ART in a timely fashion.
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ART usually includes three-drug combinations of:
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Nucleoside reverse transcriptase inhibitors (NRTI): tenofovir disoproxil fumarate (TDF), tenofovir alafenamide fumarate (TAF), zidovudine (AZT), didanosine (DDI), lamivudine (3TC), emtricitabine (FTC), stavudine (D4T), and abacavir (ABC).
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Protease inhibitors (PI): saquinavir, amprenavir, indinavir, nelfinavir, agenerase, lopinavir/ritonavir, atazanavir, and darunavir.
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Nonnucleoside reverse transcriptase inhibitors (NNRTI): nevirapine, delavirdine, efavirenz (EFV), etravirine, and rilpivirine.
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Integrase inhibitors: raltegravir, elvitegravir, and dolutegravir.
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Others: maraviroc and enfuvirtide.
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The protease inhibitors ritonavir or cobicistat should be used in combination with other protease inhibitors to obtain more sustained drug levels. Usual initial dosing regimens include two NRTIs and an NNRTI or PI or integrase inhibitor. Currently, integrase inhibitors are recommended as first-line drugs because of tolerability. Examples of initial regimens recommended by the guidelines:
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Dolutegravir/abacavir/lamivudine (in patients who are HLA-B∗5701 NEGATIVE)
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Dolutegravir plus tenofovir/emtricitabine∗
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Elvitegravir/cobicistat/tenofovir/emtricitabine
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Raltegravir plus tenofovir/emtricitabine
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Darunavir/ritonavir plus tenofovir/emtricitabine
Previous first-line drugs, including efavirenz/tenofovir/emtricitabine and rilpivirine/tenofovir/emtricitabine, are now considered alternative regimens.
All these drugs have unique and class-specific side effects and require careful and expert follow-up to achieve optimal antiviral effects, ensure compliance, and maintain efficacy. Antiviral response should be monitored by baseline HIV viral load and CD4 count and repeat measurement at 2 weeks and 4 weeks into treatment and then periodically (every 3-6 months) to ensure viral suppression.
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An approach to evaluating chronic diarrhea in patients with HIV infection is described in Fig. E2, the approach to the acutely ill HIV-infected patient is outlined in Fig. E3, and the evaluation of HIV-positive patients with respiratory complaints is described in Figs. E4 and E5. The approach to a patient with CNS signs and symptoms is described in Fig. E6. Fig. E7 describes the management of CNS mass lesions. Fig. E8 presents an approach to cardiac dysfunction.
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Genotypic resistance testing is strongly encouraged for all patients initiating treatment and for any patient failing antiretroviral therapy. Poor adherence to therapy, however, often underlies virologic failure.
Disposition
The outlook for AIDS has changed radically since the advent of ART therapy from an essentially fatal disease to a chronic medical illness compatible with long-term survival and remarkably good quality of life. Patients should be aggressively treated for severe illnesses as outcomes following ICU admissions remain good. This is accomplished through expert and continuous follow-up, use of ART, and careful detail to compliance to medications and lifestyle modification.
Referral
All patients with AIDS should be referred to a physician knowledgeable and experienced in the management of the disease and its complications
Related Content
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Acquired Immunodeficiency Syndrome (AIDS) (Patient Information)
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Candidiasis, Cutaneous (Related Key Topic)
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Candidiasis, Invasive (Related Key Topic)
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Cryptosporidium Infection (Related Key Topic)
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Cytomegalovirus Infection (Related Key Topic)
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Herpes Simplex (Related Key Topic)
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Histoplasmosis (Related Key Topic)
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HIV Cognitive Dysfunction (Related Key Topic)
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Human Immunodeficiency Virus (Related Key Topic)
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Kaposi Sarcoma (Related Key Topic)
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Pneumonia, pneumocystis jiroveci (carinii) (Related Key Topic)
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Progressive Multifocal Leukoencephalopathy (Related Key Topic)
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Toxoplasmosis (Related Key Topic)
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Tuberculosis (Related Key Topic)