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KEY POINTS
In addition to immunologic mechanisms, physical (motility), chemical (gastric acidity), and microbiologic (normal colonizing flora) factors normally protect the gastrointestinal tract against infection.
Esophagitis, most commonly caused by Candida albicans or herpes simplex virus, may be underrecognized among patients in the intensive care unit.
Infection with Helicobacter pylori may play a role in the pathogenesis of gastric stress ulceration among critically ill patients.
The epidemiology and microbiology of diarrheal illness is significantly different among patients in the critical care unit than is observed in the community setting. Most infectious diarrhea in the ICU is hospital-acquired and is usually attributable to Clostridium difficile.
A systematic approach to the critically ill patient with diarrhea includes consideration of pathogens that cause noninflammatory, inflammatory, and hemorrhagic diarrhea.
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Gastrointestinal (GI) infections account for substantial morbidity and mortality among critically ill patients. Patients in the ICU are especially susceptible to hospital-acquired GI infection, in part due to the severity of other comorbid conditions, age, immunocompromised states, nutritional factors, general disruption of the microbiome, and invasive interventions, leading to an environment that can promote the development of severe disease. While managing patients with a primary critical illness, it is imperative that clinicians remain alert for opportunities to prevent, recognize, and manage GI infections.
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Any discussion of GI infections among critically ill patients must begin with a consideration of the host defenses that normally protect the alimentary tract. As such, the first section of this chapter is devoted to a description of the unique nonimmunologic mechanisms normally active in the GI tract. Particular consideration is given to the means by which these defenses may be compromised in patients in the ICU. Following this introduction, the clinical manifestations of infection affecting each segment of the GI tract are discussed (Table 79-1). In addition to describing the microbiology associated with each syndrome, a rational diagnostic and therapeutic approach is offered, based on the most up-to-date experience and published research. The chapter concludes with an expanded discussion of the unique clinical challenges presented by the patient in the ICU with Clostridium difficile infection.
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GI motility, in addition to its central role in normal digestion, is one of the principal host defenses against infection. By continuously flushing the lumen of the GI tract, normal motility prevents the accumulation of ...