Gastrointestinal hemorrhage.

Two types of upper gastrointestinal bleeding can be differentiated in the critical care setting: bleeding caused by a gastroenterologic disorder or bleeding that develops as a complication of a nongastroenterologic critical illness. A clinical approach to upper gastrointestinal bleeding is presented. Lower gastrointestinal hemorrhage and the diagnosis of gastrointestinal bleeding in infants and children are also briefly discussed.