ABSTRACT & COMMENTARY
Ebola Virus Disease and the ICU Clinician
By David J. Pierson, MD, Editor
As hospitals in the United States and other resource-intensive countries prepare for the care of patients with possible Ebola virus disease, the greatest impact on its clinical outcome and further spread will most likely come from the application of existing basic critical-care and infection-control principles.
Fowler RA, et al. Caring for critically ill patients with ebola virus disease. Perspectives from West Africa. Am J Respir Crit Care Med 2014;190:733-737.
The form of viral hemorrhagic fever now known as Ebola virus disease (EVD) has occurred sporadically, primarily in rural areas of tropical Africa, since 1976. However, this year it has exploded both epidemiologically and as a worldwide news phenomenon because of its first outbreak in a major metropolitan area.1 With 23 co-authors representing the World Health Organization and both academic and governmental institutions in seven countries, Fowler provides a current overview of EVD focused on its pathophysiology, clinical presentation, and management needs, based on their experience with this current outbreak. Ebola is everywhere in the news right now, a source of concern and even panic among both health professionals and the public. Amidst a welter of popular information of variable accuracy and authority, several other scholarly resources on EVD and its management have recently appeared.2-4 The report by Fowler et al places current information about this highly lethal and frightening condition in perspective for critical care clinicians, for whom an accurate appreciation of EVD and its management is becoming necessary, even if they do not personally encounter cases.
Of the five species of Ebolavirus in the RNA virus family Filoviridae, three have been associated with large outbreaks of human disease. The natural reservoir is fruit bats and possibly other mammals, and both humans and nonhuman primates are susceptible end hosts. The virus is transmitted through direct mucous membrane or percutaneous exposure to infected body fluids, most often stool, vomitus, or blood, as well as by contact with materials and surfaces contaminated with these substances. Once it enters the body, the virus is carried to regional lymph nodes by monocytes, macrophages, and dentritic cells, and subsequently disseminates hematogenously to the liver and spleen.
Clinically, EVD starts as a febrile, flu-like illness with fatigue and myalgias, with prominent gastrointestinal symptoms such as anorexia, nausea, and abdominal discomfort. These are followed by vomiting and diarrhea, leading to intravascular volume depletion which commonly proceeds to severe lactic acidosis, profound hypokalemia, and progressive renal insufficiency. A maculopapular rash may occur. Lymphopenia and thrombocytopenia are common, although anemia is infrequent. Hepatocellular injury with elevated transaminases is frequent, but respiratory involvement (hypoxemia) is not part of the typical presentation. In some cases there is hemorrhage from the gastrointestinal tract and mucous membranes, and death in fatal cases is usually from unsupportable shock and multisystem organ failure. There are no proven EVD-specific medical therapies. However, aggressive prevention of intravascular volume depletion, correction of electrolyte abnormalities, and prevention of the complications of shock can be expected to substantially reduce the high mortality rate that has so far been observed in this outbreak.
Infection control and public health aspects of managing EVD are vitally important. Substantial transmission of EVD to health care workers has occurred in the current outbreak in West Africa, in the context of severe shortages of protective equipment and other materials. Many cases have occurred in family members who had close contact with gravely ill patients, and in others who transported corpses or prepared them for burial.
COMMENTARY
As Fowler and colleagues point out, "The constellation of limited public health infrastructure, low levels of health literacy, few acute care and infection prevention and control resources, densely populated areas, a mobile population, and a highly transmissible and lethal viral infection have created a perfect storm" in the current West African EVD outbreak. Among its numerous catastrophic effects, this perfect storm almost certainly means that mortality among those who contact EVD will be substantially higher there than among any persons who might present with the disease and be cared for in resource-rich countries like the United States.
In addition to advocating for all appropriate education, personnel, infrastructure, and materials being made available in West Africa and other resource-constrained environments, the authors identify five key principles for improving outcomes from EVD, both in those settings and in the ICUs of resource-rich environments like the United States:
- Consideration of EVD as another transmissible infection-related critical illness that will benefit from goal-directed supportive and specific intensive care;
- Recognition that the predominant EVD clinical syndrome is gastrointestinal, with intravascular volume depletion and metabolic derangements the greatest threats to the patient;
- Emphasis on the primary role of basic laboratory tests in identifying and tracking these derangements during management;
- Appreciation that the fundamental skills already possessed by critical care clinicians constitute the main needs of patients with EVD; and,
- Anticipation that patient outcomes will be improved through application of these principles.
Patients suspected of having EVD are now being admitted to hospitals in this country. Even if one’s own institution is not one of them, being prepared for the possibility will be important for at least the next several months. In addition to the resources cited above, here are two more of direct relevance to ICU clinicians and administrators: The World Health Organization’s online 24-page infection-control document5 provides practical guidance covering general and direct patient care, waste management, and such non-patient-care topics as diagnostic laboratory activities, movement and burial of human remains, post-mortem examinations, and managing possible virus exposures through blood and other body fluids. In addition, the Centers for Disease Control and Prevention has a comprehensive, updated website on Ebola for health care workers covering many aspects of the topic.6
REFERENCES
- World Health Organization. Ebola Virus Disease. Fact Sheet no. 103 (updated September 2014). http://www.who.int/mediacentre/factsheets/fs103/en/. Accessed October 7, 2014.
- Ansari AA. Clinical features and pathobiology of Ebolavirus infection. J Autoimmun 2014; Sep 23. pii: S0896-8411(14)00130-9. doi: 10.1016/j.jaut.2014.09.001. [Epub ahead of print.]
- WHO Ebola Response Team. Ebola virus disease in West Africa - The first 9 months of the epidemic and forward projections.
N Engl J Med 2014; Sep 22. [Epub ahead of print.]
- Feldmann H, Geisbert TW. Ebola haemorrhagic fever. Lancet 2011;377:849-862.
- http://www.who.int/csr/resources/publications/ebola/filovirus_infection_control/en/. World Health Organization. Infection prevention and control guidance for care of patients in health-care settings, with focus on Ebola. August 2014. Accessed October 7, 2014.
- http://www.cdc.gov/vhf/ebola/hcp/index.html. Accessed October 8, 2014.
