Hematochezia - Causes and Symptoms

Definition

The term hematochezia identifies the emission of faeces painted with blood or mixed with it ; blood that, in most cases, originates in the anus, rectum or descending colon.

if the feces are painted with blood, it means that the hemorrhage occurred in the terminal part of the colon, where the feces are already formed (left side of the transverse colon, descending colon, sigma or rectum);
if the feces are mixed with blood (the blood is mixed with them), it means that the bleeding has occurred in the small intestine, in the right colon or in the right side of the transversus, sites in which the fecal cylinders are not yet well formed.

An important feature in order to speak of hematochezia is the presence of fresh (undigested) blood in the faeces. In fact, hematochezia must be distinguished from melena with picee feces.

The term melena indicates the emission of faeces containing digested blood, which gives the faeces a blackish color and a sticky appearance. In hematochezia, on the other hand, the blood - having not been digested - is red in color .

In general, therefore, the hematochezia indicates the presence of hemorrhage in the lower digestive tract, in particular at the level of the final tracts of the small intestine or colon. Conversely, bleeding from the upper digestive tract (esophagus, stomach, duodenum) is associated with melena.

It should also be noted that an important bleeding of the upper tract, associated with an accelerated intestinal transit, can be accompanied by the presence of hematochezia; on the other hand, bleeding from the lower digestive tract associated with poor intestinal peristalsis may result in melena with picee feces. This is because the bacterial flora and enzymes present in the intestine can digest lost blood with the upper digestive hemorrhage. Generally, the more this is massive and the greater the probability that hematochezia occurs, since the blood acts as a laxative (for distension of the enteric walls) accelerating the intestinal transit. According to a rough estimate, it takes about 14 hours for the blood to be digested by enzymes in the intestinal lumen.

Hematochezia should also be distinguished from rectorragia (or proctorrhagia), which indicates the loss of bright red blood from the anus during, after or independently of defecation. The two conditions are however not easily distinguishable and the elements of divergence reside in the quantity of blood in the faeces, which is greater in the rectorragia, and in the possible independence of the latter from defecation. Furthermore, the rectorrhagia may also depend on bleeding that drains into the rectum but does not originate from it.

Blood stains in toilet paper or dripping bleeding after defecation are a typical sign of hemorrhoids. Blood streaks in toilet paper associated with intense anal pain during defecation are instead a typical sign of anal fissures.

Red stools can also be related to the abundant consumption of red colored foods (tomato juice, red fruit and beetroot).