The clinical significance and pathophysiology of stress-related gastric mucosal hemorrhage

Critically ill patients admitted to intensive care units (ICUs) develop a spectrum of gastroduodenal mucosal lesions that may result in mucosal hemorrhage and subsequent morbidity and mortality. Although stress-related mucosal lesions may be detected endoscopically in most critically ill patients, the incidence of clinically significant bleeding from these lesions is difficult to establish because of the heterogeneity in patient populations, the definitions of bleeding, and the methods of monitoring in various studies. Bleeding occurs overall in approximately 16% of patients not receiving prophylaxis, but the incidence of life-threatening hemorrhage appears to be much lower (less than 6%). In light of the increasing use of pharmacologic prophylaxis in ICUs, the clinical impact of stress-related bleeding and its prophylaxis is discussed in terms of bleeding incidence, morbidity and mortality, cost, and potential side effects. The pathophysiology of stress-related mucosal ulceration involves the complex interaction of gastric luminal factors, alterations in blood flow and intramucosal pH, and alterations in numerous factors that are normally responsible for maintaining an intact mucosa. The pathophysiology of stress ulceration is discussed, with an emphasis on cause-and-effect relationships, evolving areas of investigation, and implications for prophylaxis and treatment.