<unk>  can be roughly divided into two clinical syndromes: upper<unk>  and lower<unk> . About 2/3 of all GI bleeds are from upper sources and 1/3 from lower sources. Common causes of<unk>  include infections, cancers, vascular disorders, adverse effects of medications, and blood clotting disorders. Obscure<unk>  (OGIB) is when a source is unclear following investigation. Upper gastrointestinal Upper<unk>  is from a source between the pharynx and the ligament of Treitz. An upper source is characterised by hematemesis (vomiting up blood) and melena (tarry stool containing altered blood). About half of cases are due to peptic ulcer disease (gastric or duodenal ulcers). Esophageal inflammation and erosive disease are the next most common causes. In those with liver cirrhosis, 50–60% of<unk>  is due to esophageal varices. Approximately half of those with peptic ulcers have an H. pylori infection. Other causes include Mallory-Weiss tears, cancer, and angiodysplasia. A number of medications are found to cause upper GI bleeds. NSAIDs or COX-2 inhibitors increase the risk about fourfold. SSRIs, corticosteroids, and anticoagulants may also increase the risk. The risk with dabigatran is 30% greater than that with warfarin. Lower gastrointestinal Lower<unk>  is typically from the colon, rectum or anus. Common causes of lower<unk>  include hemorrhoids, cancer, angiodysplasia, ulcerative colitis, Crohn's disease, and aortoenteric fistula. It may be indicated by the passage of fresh red blood rectally, especially in the absence of bloody vomiting. Lower<unk>  could also lead to melena if the<unk>  occurs in the small intestine or proximal colon.
Gastrointestinal bleeding
Internal bleeding
Lower gastrointestinal bleeding
Upper gastrointestinal bleeding
Enteropathy
Rectal bleeding
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