Melena (Intussusception)

anus_9a_n.jpg: Napkin with a bloody and mucous specimen of stool. In the close-up picture $$anus_02??££of another patient§§ please notice the jagged border of the stool on the right side and at the bottom of the picture. In this specimen the mucus predominates which is secreted from the tip of the intussuscept into the colonic lumen. The brown and jagged line which is recognizable at the upper right border of the stool corresponds to blood, too, as in the close-up picture which is diffused farther into the periphery than the mucus. anus_9b_n.jpg: Drawing of the pathophysiology of the described stool characteristics in acute intestinal invagination. Following the intussusception the mesenteric vessels of the invaginated intestinal segment are compromised; the venous stasis at the beginning leads to an increased secretion of mucus and to a diapedesis bleeding into the lumen which are evacuated as melena or more precisely as red current jelly stool.