Gastrointestinal, or GI, bleeding, is any loss of blood from the GI tract. Blood loss can be occult, or lost in small undetectable amounts, or in larger life-threatening amounts. In any situation, blood loss is a condition that needs to controlled. The loss of blood also means the loss of iron; when iron is lost, supplementation is necessary.
Synthesis of Blood
Blood is composed of formed elements, or blood cells, and plasma. The blood is made in the bone marrow. Red blood cells deliver oxygen to the tissues. When a problem with red blood cell production exists, it affects the delivery of oxygen. Iron, is stored in the bone marrow and is necessary for the production of red blood cells.
Significance
Red blood cells contain the protein hemoglobin. Hemoglobin allows the red blood cell to transport oxygen in blood. A red blood cell with defective hemoglobin is incapable of carrying oxygen. The formation of hemoglobin requires iron; therefore, when iron is deficient, functional hemoglobin is also deficient. Iron deficiency anemia, a condition caused by lack of iron in the blood, causes shortness of breath, generalized weakness and fatigue.
Symptoms
GI bleeding is categorized into upper and lower GI bleeding. Upper GI bleeding is identified as a bleeding from any region of the GI tract between the esophagus and the duodenum, or the first portion of the small intestine. Lower GI bleeding is blood loss below the duodenum.
Upper GI bleeding is usually suspected when a person passes a dark tarry stool called melena. When a person complains of bright red blood in the stool, this indicates a lower GI bleed. Changes to stool color is only evident with significant bleeding, but the absence of stool color changes does not rule out GI bleeding.
Causes
Ulcers and erosions, common in the upper GI, may lead to bleeding. Ulcers in the stomach and duodenum are sometimes caused by increased acid production in the stomach. Certain infections may also lead to irritation and ulceration of the GI. In alcoholics, rupture of the esophagus from forceful vomiting may also lead to bleeding.
Colon cancer, which commonly presents in the lower GI, may also cause bleeding. Other common causes of lower GI bleeding include inflammatory bowel disease, diverticular disease, hemorrhoids and anal fissures.
Treatment
Chronic low-volume blood loss, is typically treated with iron supplementation. Iron is supplemented orally as ferrous sulfate since this form of iron is better absorbed in the GI tract. Iron may also be supplemented intravenously or intramuscularly but only when oral supplementation is ineffective. Diseases that affect portions of the GI tract involved with iron absorption may reduce the effectiveness of oral iron supplementation. Constipation and darkening of stool are common side effects of iron supplementation.
Massive GI bleeding is usually accompanied by changes in blood pressure; treatment in this case is stabilization with fluid resuscitation and blood transfusion, both of which are prerequisites for investigating cause of bleeding.
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