- The acquired immunodeficiency syndrome (AIDS) is caused by chronic infection with the human immunodeficiency virus (HIV), which through its relentless replication causes progressive depletion of T-helper lymphocytes leading to severe cellular immunodeficiency.
- In the absence of treatment, after a variable period, usually years from infection, multiple opportunistic infections or neoplasms characteristic of AIDS develop. Despite substantial progress in antiretroviral therapy, cure of the disease remains elusive.
- HIV transmission is limited to sexual exposure (homosexual or heterosexual), exposure to blood or blood products (including transplanted organs), and perinatal exposure (transplacentally, at the time of delivery, or through lactation).
- HIV cannot be transmitted through casual contact. Universal precautions, however, should be implemented and enforced to minimize the risk of occupational exposure to HIV as well as other infectious agents. The rate of seroconversion following a single accidental needle stick or mucous membrane exposure appears to be well below 1%.
- Combination antiretroviral therapy has been shown to prolong survival as well as disease-free interval. The widespread availability of plasma viral load monitoring and increasing access to genotype resistance testing in developed countries have led to further optimization of therapy and hence further improvement in outcomes.
- Acute respiratory failure (ARF) secondary to Pneumocystis carinii pneumonia (PCP) is a frequent cause of ICU admission among HIV-infected individuals.
- PCP usually is diagnosed in the ICU using bronchoalveolar lavage (BAL). BAL fluid always should be processed to allow identification of P. carinii, fungi, common bacteria, mycobacteria, and viruses.
- PCP-related ARF should be treated aggressively with specific antimicrobials, adjunctive systemic corticosteroids, and oxygenation support.
- The mortality of PCP-related ARF has decreased substantially with the use of adjunctive systemic corticosteroids. Patients developing ARF despite corticosteroid treatment, however, continue to have a dismal prognosis.
- Initiation of highly active antiretroviral therapy or revision of a failing regimen should be delayed until completion of PCP therapy because of the risk of pulmonary deterioration related to PCP immune reconstitution syndrome.
- The issue of life support should be discussed early and reassessed frequently with HIV-infected individuals. ICU admission and life support, however, should be discouraged for patients with multiple life-threatening complications for which there is no effective therapy. Because the outlook of AIDS and its related diseases is changing rapidly, rigid policies regarding ICU eligibility should be strongly discouraged.
Human Immunodeficiency Virus Infection
The acquired immunodeficiency syndrome (AIDS) is caused by chronic infection with the human immunodeficiency viruses (HIV-1, HIV-2). Continuous HIV replication leads to progressive dysfunction and gradual depletion of the helper T-lymphocytes or CD4+ lymphocytes.1,2 It is clear, however, that HIV can infect other cells, including macrophages and B-lymphocytes. Eventually, this results in the development of the otherwise unusual opportunistic infections and neoplasms characteristic of AIDS.
The total number of people infected with HIV/AIDS globally as of December 2000 has been estimated to be 58 million, of whom 21.8 million have died since the beginning of the epidemic. The number of people in the United ...