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CHAPTER 69: Human Immunodeficiency Virus (HIV) and AIDS in the Intensive Care Unit 625

treatment of malignant and nonmalignant hematologic diseases. INTRODUCTION
Blood. February 1, 1998;91(3):756-763. It has been over three decades since the initial reports of unusual oppor-
• Storb R. Nonmyeloablative preparative regimens: how relevant for tunistic infections and malignancies heralded the onset of the human
acute myelogenous leukemia? Leukemia. April 2001;15(4):662-663. immunodeficiency virus (HIV) epidemic. Over the last 30 years, our
1,2
• Uys A, Rapoport BL, Anderson R. Febrile neutropenia: a prospec- understanding of HIV transmission, pathogenesis, and viral replica-
tive study to validate the Multinational Association of Supportive tion has advanced considerably. The use of combination antiretroviral
Care of Cancer (MASCC) risk-index score. Support Care Cancer. therapy (ART) has been shown to halt progressive immunologic decline
2004;12(8):555-560. with concomitant improvements in morbidity and mortality due to
HIV-related acquired immunodeficiency syndrome (AIDS). As a
3,4
result, survival rates among HIV-infected individuals who are able to
https://kat.cr/user/tahir99/
REFERENCES access ART may begin to approximate those of the general population.
5,6
In the United States, recent epidemiologic data suggest that mortality
Complete references available online at www.mhprofessional.com/hall due to HIV infection has now dropped below that related to hepatitis
C infection. Similar benefits have now also been demonstrated in
7
CHAPTER Human Immunodeficiency resource-limited settings where ART programs have been implemented,
such as in South Africa, Zambia, Uganda, and South East Asia.
10
8
9
11,12
The proportion of AIDS cases requiring either hospitalization or
69 Virus (HIV) and AIDS in the admission to the ICU has declined since the introduction of ART in
Intensive Care Unit
1996. In recent years, HIV-related hospitalizations are less often due to
opportunistic diseases compared with the pre-ART era. Management of
Mark Hull patients presenting to the intensive care unit (ICU) should reflect these
Adam M. Linder developments, and HIV infection alone should not affect decisions to
JSG Montaner pursue life-saving interventions among patients requiring ICU support.
James A. Russell HIV-infected patients are now as likely to present with common rea-
sons for admission such as trauma, drug-related overdose, or bacterial
sepsis, as they are to present with HIV-related complications. That is,
KEY POINTS HIV/AIDS is now an important underlying condition as opposed to the
cause of ICU admission. Physicians working in the ICU must remain
• The acquired immunodeficiency syndrome (AIDS) is caused by informed regarding the management of common opportunistic infec-
chronic infection with the human immunodeficiency virus (HIV), tions that remain a cause of hospitalization for HIV-infected individuals.
which through its relentless replication causes progressive depletion Physicians caring for critically ill patients who have HIV/AIDS must
of T-helper lymphocytes leading to severe cellular immunodeficiency. also become familiar with antiretroviral therapies and the need to avoid
• In the absence of treatment, after a variable period, usually years inadvertent harm due to treatment discontinuations, or toxicities arising
from infection, multiple opportunistic infections or neoplasms due to drug-drug interactions.
characteristic of AIDS develop.
• Combination antiretroviral therapy has been shown to prolong survival HIV EPIDEMIOLOGY
as well as disease-free interval. Furthermore, antiretroviral therapy has
emerged as an effective primary prevention. Despite substantial prog- There were an estimated 34 million individuals living with HIV/AIDS
13
ress in antiretroviral therapy, cure of the disease remains elusive. worldwide in 2010. The majority of individuals (22.9 million) reside in
sub-Saharan Africa, with an estimated 2 to 3 million individuals living in
• Acute respiratory failure (ARF) secondary to Pneumocystis jirovecii North America and Europe. Globally, the incidence of HIV infection has
pneumonia (PJP) is now less common than during the early years declined from 3.0 million new infections in 2000 to 2.7 million in 2010.
of HIV/AIDS as a cause of ICU admission among HIV-infected Within the United States, by the end of 2008 there were an estimated
individuals with advanced HIV infection. 1.1 million individuals living with HIV—of whom 20% are thought to be
• PJP usually is diagnosed in the ICU using bronchoalveolar lavage undiagnosed. Estimated 40 to 60,000 new diagnoses occur annually. 14-16
14
(BAL). BAL fluid should always be processed to allow identification The majority of diagnoses are occurring in men who have sex with men
of P jirovecii, fungi, common bacteria, mycobacteria, and viruses. (MSM), with heterosexual transmission now accounting for approxi-
• The mortality of PJP-related ARF has decreased substantially with mately 30% of diagnoses. Since the widespread adoption of HIV
14
the use of adjunctive systemic corticosteroids. Patients developing screening of donated blood, parenteral transmission of HIV is limited
ARF despite corticosteroid treatment, however, continue to have a almost exclusively to intravenous drug use. Finally, the infection can
dismal prognosis. also be transmitted perinatally, although this is rare in a North American
• Because of better treatment and prolonged survival, more patients context. Uptake of ART has resulted in decreases in AIDS diagnoses and
are admitted to ICU who have HIV/AIDS as an underlying illness AIDS-related mortality (ie, patients are HIV positive without complica-
as opposed to the cause of ICU admission. tions of AIDS) within the United States. Despite advances in therapy,
• HIV cannot be transmitted through casual contact. Universal pre- a significant proportion of individuals estimated to be infected within
the United States remain undiagnosed, linkage to care among HIV-
cautions, however, must be implemented and enforced routinely
to minimize the risk of occupational exposure to HIV (as well infected individuals who are aware of their status remains incomplete,
and accordingly such patients may present with common opportunistic
as other infectious agents). The rate of seroconversion following
a single accidental needle stick or mucous membrane exposure infections and morbidities related to untreated HIV.
appears to be well below 1%.
• The issue of life support should be discussed early and reassessed HIV PATHOGENESIS
frequently with HIV-infected individuals. Because the outlook Briefly, HIV preferentially infects T lymphocytes bearing the surface
of AIDS and its related diseases has improved dramatically, rigid marker CD4, the so-called helper T cells. This tropism is mediated
policies regarding ICU admission are not appropriate. through a specific interaction between GP160, a viral envelope glyco-
protein, and the CD4 molecule itself. HIV is also capable of infecting

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