Bleeding From the Rectum
BLEEDING from the anal orifice is a sign which demands investigation. Since the rectum is the terminus of the gastrointestinal tract, blood which emanates therefrom may represent any portion from mouth to perineum. Careful questioning of the patient regarding the character of the bleeding is important, since blood originating from any part of the tract is fairly characteristic of that section. In general, red blood represents bleeding from the cecum downward, and black bleeding (melena) from the mouth through the small intestine. However, exceptions may occur. Truly massive hemorrhage from esophageal varices, hiatus hernia, gastric neoplasm or peptic ulcer may irritate the small and large intestine so that peristalsis will hurry blood to the rectum while it is still bright red. Fortunately, vomiting which occurs in most cases of massive gastric hemorrhage will suggest localization.
Melena, or tarry stool, represents blood altered by its passage through the small intestine. This form of blood may appear mixed with stool or as sticky, foul smelling, tarry masses. If such blood has come through the upper tract more rapidly than chyme, it may not have been completely changed and may appear dark red or impart a Burgundy wine color to the water in the bowl. Such stool gives a four plus benzidine or guaiac reaction. Iron compounds prescribed for anemia produce a black, tarry stool. Ingestion of beets produces a dark red stool, sometimes assumed to be blood. Table 1 lists the common causes of melena.
Colonic and Rectal Bleeding
Bright red. . .