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Gastrointestinal (GI) bleeding produces alarm and anxiety in parents and physicians. Most causes of GI bleeding do not result in significant blood loss, and many cases of GI bleeding cease spontaneously. Larger volume bleeding can lead to hemodynamic compromise that requires aggressive resuscitation and intervention. A systematic approach to diagnosis is required.
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DEFINITIONS
Hematemesis: Vomiting of either fresh or altered blood (such as coffee grounds emesis). Implies recent or continuing bleeding proximal to the ligament of Treitz.
Hematochezia: Bright red blood per rectum or maroon-colored stools. Usually originates in the colon. Upper GI hemorrhage can also present with hematochezia secondary to decreased transit time in infants or with brisk bleeding. Blood-streaked stools suggest a bleeding source in the rectum or anal canal.
Melena: Dark or black, tarry stools with a characteristic odor. Indicative of blood that has been in the GI tract for a long time, allowing the denaturation of hemoglobin by bowel flora. Melenic stools are typically from a hemorrhage originating proximal to the ileocecal valve.
Occult blood: Presence of blood in the stool that is not visible but is confirmed by chemical testing (i.e. guaiac.)
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The history can be helpful in identifying the cause and location of bleeding in the GI tract (Table 25-1). Quantifying the volume and acuity of blood loss is important in understanding the risk of hemodynamic compromise. The character of the blood may indicate a more likely location of bleeding, though brisk bleeding from an upper GI source can cause hematochezia. Fever, recent travel, or known sick contacts may implicate an infectious source, while longer-standing symptoms and associated weight loss may indicate a more serious underlying cause such as inflammatory bowel disease (IBD). A complete medication history is essential, including recent use of nonsteroidal anti-inflammatory drugs (NSAIDs) or antibiotics. Certain foods (e.g. beets) or medications can also cause a red discoloration of GI fluids and be mistaken for hematemesis or melena.
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