Severe upper gastrointestinal bleeding. Part I: Causes, pathogenesis and methods of diagnosis.

: Upper gastrointestinal bleeding is a common gastrointestinal emergency associated with significant socioeconomic impact, morbidity and mortality. The aetiology of upper gastrointestinal bleeding has been reviewed, including the pathophysiological mechanisms of acid peptic and gastric mucosal disease. The initial diagnosis and therapeutic approach to the bleeding patient has been outlined.