Change In Stool Color : Causes, Symptoms, Diagnosis & Treatment

• General Characteristics
• Development Mechanism
• Classification

A change in the color of feces is the appearance of atypical staining of feces, which can be observed both in absolutely healthy people and against the background of various diseases. Sometimes a symptom has physiological prerequisites - eating certain foods or taking medications, but more often a change in color indicates a pathology of the digestive tract. To identify the causes of the symptom, ultrasound, endoscopic, x-ray, laboratory research methods are used. To return the normal color of feces, drugs are used to eliminate the root cause of the color change.

general characteristics

The appearance of an unusual color of feces is an objective symptom that patients always notice. The color of the feces is different - from grayish-white to black. In this case, the process of defecation is sometimes accompanied by pain, discomfort in the abdomen. With a visible change in the characteristics of feces, patients often experience negative psycho-emotional sensations caused by the fear of a serious illness. If the color change is of a physiological nature, the person does not experience any unpleasant symptoms either during bowel movements or during the day.

A change in the color of feces is often accompanied by other dyspeptic disorders: nausea, vomiting, abdominal pain, a violation of the frequency of stools and the consistency of feces, which indicates the development of diseases of the digestive tract. The combination of pale gray stools and dark urine usually indicates hepatitis, other acute inflammatory diseases of the liver. The appearance of black, brick or red feces during defecation is typical for bleeding from the gastrointestinal tract of varying intensity and requires an immediate visit to a gastroenterologist.

Development mechanism

Normal stools are brown in color, which can vary from light to dark shades depending on eating habits. This color is due to the presence of bilirubin metabolism products - stercobilin and mesobilifuscin. A change in the color of feces occurs when coloring substances enter the composition of food or drugs, the presence of pathological impurities (blood, bile pigments). With diarrhea, the feces become golden yellow, because their accelerated passage prevents the conversion of direct bilirubin to stercobilin.

Colorless or gray stools are characteristic of the occurrence of mechanical obstacles to the outflow of bile into the intestines (cholelithiasis, volumetric formations of the pancreas, duodenum), as a result of which there are no coloring substances in the feces, which are normally formed from conjugated bilirubin. Stools become greyish and clay-like when oral administration of barium sulfate contrast is due to chemical reactions in the stomach and intestines.

Faeces may turn greenish, which is often a normal variant and is caused by eating a lot of fresh green vegetables. These products are rich in the pigment chlorophyll, which is not destroyed by digestive enzymes and provides a characteristic color. A change in the color of feces to green also occurs with pathological diarrhea, when biliverdin, a precursor of bilirubin, is massively released along with bile, which does not have time to go through all the stages of chemical transformations in the intestine.

Black staining of stool appears when bismuth salts are taken, which form insoluble complexes with black gray under the influence of saliva. Dark coloration also occurs when iron salts enter the stool. Tar-like black stools (melena) develop with bleeding from the stomach and upper portions of the small intestine. Dark staining is due to the conversion of hemoglobin to hematin hydrochloride under the action of enzymes and intestinal flora. When bleeding from the colon and rectum, hemoglobin is not destroyed, so the stools are red.

Classification

There are physiological changes in the coloration of feces, associated with certain dietary habits or the use of a number of medications, and pathological, caused by various inflammatory and destructive processes in the gastrointestinal tract, the biliary system. To make a preliminary syndromological diagnosis, a classification is used taking into account the nature of the color of the feces:

• Feces are grayish white . Greyish "clay" feces are often passed for several days after oral administration of a barium sulfate contrast agent. The pale color of feces is associated with a violation of the flow of bile into the duodenum in biliary pathology, hepatitis, pancreatic neoplasia.
• Yellow stool . Yellow staining is usually observed when the digestion of food is disturbed due to enzyme deficiency. This color is typical for diseases of the pancreas, malabsorption syndrome, celiac disease. A golden yellow color often indicates an excess of unchanged bilirubin.
• Green stool . The change in coloration appears with a large number of lettuce leaves and green vegetables in the diet, a greenish-black color is associated with taking iron supplements. The color changes to green with diarrhea of ​​various origins and severe dysbacteriosis, when the rate of transit of feces through the intestines is disturbed.
• Red stool . The appearance of a brick-red color is normally associated with excessive consumption of tomatoes, red berries and vegetables. A change in the color of feces to bright red usually occurs with heavy bleeding from the lower gastrointestinal tract, which occurs with anal fissures, hemorrhoids, and ulceration of neoplasms.
• Black feces . The stool becomes black when taking activated charcoal and bismuth, blueberries and black currants. Black, tarry feces (melena) is a dangerous symptom that indicates profuse bleeding from the stomach and upper small intestine.