Acute Intussusception vs. Melena
Left picture: In this case, a so-called red current jelly stool is present which is characteristic for intussusception, but may also be observed in intestinal polyps. On looking closely it is not stool, rather it is viscid mucus which is mixed up with fresh blood; notice the red halo in the periphery of the evacuation. Right picture: The evacuation consists mainly of masses of older blood; notice the homogeneously black to dark-red discolored masses and the dark-red halo around the pieces of coagulated blood. Such a passage of blood may be observed in Meckel´s diverticulum or intestinal duplication with a moderately bleeding ulcer, or in severe upper gastro-intestinal bleeding and in Henoch-Schönlein purpura with involvement of the intestine. The passage of blood by the anus has different manifestations; for the differetial diagnosis of melena it is essential to inspect the diapers and the pants or panties precisely.
Left picture: On the diaper there are traces of a bloody stool. Right picture: On the baby´s napkin an evacuation of black masses is visible.