HYPOCOLIA: PATHOPHYSIOLOGY, BLOOD VALUES, BILIRUBIN - MEDICINE - 2025

The term hypocolia refers to the change in the color of the stool due to the decrease in the amount of bilirubin in the colon. Bilirubin is the pigment that produces its coloring, so when the stool is lighter than normal, taking on a very light or beige tone, the patient may be affected by hypocholia.

It is a sign found in those with conditions that compromise the secretion of bile into the digestive system. The decrease or obstruction in the passage of bile into the duodenum prevents it from being absorbed and degraded into its different elements, thus reducing the normal amount of bilirubin that reaches the colon.

By BruceBlaus. When using this image in external sources it can be cited as: Blausen.com staff (2014). "Medical gallery of Blausen Medical 2014". WikiJournal of Medicine 1 (2). DOI: 10.15347 / wjm / 2014.010. ISSN 2002-4436. - Own work, CC BY 3.0, It is usually accompanied by another sign called coluria, which is the dark coloration of the urine resulting from the excretion of bilirubin through the kidneys, and also jaundice, which is the yellow coloration of the skin and mucous membranes, due to the accumulation of this pigment in soft tissues.

It is commonly a warning sign that precedes acholia, which is the complete absence of bile pigments in the stool.

It is not specific to any disease, but it is associated with all those that affect normal bile secretion.

Hypocolia, coluria, acholia, and jaundice

Partial discoloration of the stool is known as hypocolia. It is a clinical sign that is observed in people with liver pathologies or in whom the adequate excretion of bilirubin is compromised.

If the passage of bile is partial, the stool will have some pigment. If, on the other hand, the route of excretion does not allow bile to pass through and the bilirubin does not reach the colon, the stool presents a complete discoloration known as acholia. Hypocolia is the first step to acholia.

Bilirubin is a toxic product when it is found in levels above normal. When it is free in the blood, it can be excreted through the kidneys. However, on some occasions this excretion process is not sufficient and bilirubin continues to circulate in the bloodstream.

When bilirubin is metabolized through the kidneys, the pigments turn urine a brownish color. This sign is known as choluria and is a physical manifestation that frequently accompanies hypocholia and acholia.

By Jmarchn - Own work, CC BY-SA 3.0, The bilirubin that remains circulating in the body is a heavy metabolite that ends up remaining in the soft tissues. This process causes the yellowing of the skin and mucous membranes, known as jaundice.

It differs from the yellow tone of the skin of some people, especially heavy consumers of foods rich in pigments such as beta-carotene, since in these cases the mucous membranes do not look colored.

These clinical signs are not specific for any disease, but when they are present, they guide the health professional in their diagnosis, focusing on the study of the liver and biliary system.

Bilirubin

Bilirubin is a pigmented metabolite that is part of hemoglobin. When hemoglobin breaks down, bilirubin becomes a yellow pigment whose presence in the circulation is toxic when its values ​​are above normal.

The purple color of bruises on the skin after trauma is produced by bilirubin.

Bilirubin is metabolized in the spleen and is excreted through the gallbladder into the duodenum following the digestive process. It is the pigment that gives stool its characteristic color.

Some of the bilirubin that remains in the bloodstream is excreted through the kidneys, giving the urine its color.

Metabolism and types

Red blood cells that have completed their life cycle, which is approximately 120 days, are destroyed in the spleen and their elements are excreted by different body systems.

Hemoglobin is one of the products of red blood cells, and it contains the metabolite bilirubin.

Bilirubin undergoes a process of metabolism in the liver where it is separated from hemoglobin and excreted into the gallbladder where it binds with bile salts and provides the yellow-green pigment, characteristic of bile.

Bilirubin that is not yet metabolized is called conjugated bilirubin, while bilirubin that has passed the liver phase and is stored in the bile is called unconjugated bilirubin.

Both types of bilirubin are normally found in the body without causing any type of toxic reaction. Unconjugated bilirubin continues in the bloodstream where it is excreted through the kidneys. It is the element that gives urine its yellow color.

Conjugated bilirubin is expelled along with bile into the duodenum, which is the first portion of the small intestine. From there it follows the natural course of digestion reaching the colon where it is excreted with the feces. The yellow pigment in bilirubin is what ends up giving stool its normal color.

Pathophysiology

Under normal conditions, bilirubin should be stored in the gallbladder and be expelled through its ducts that lead to the duodenum.

Once there, the bilirubin follows the path of the digestive system reaching the colon for its excretion. When it reaches the colon, it is the main pigment that gives stool its characteristic color.

When there is some disorder that prevents the passage of bile from the gallbladder to the duodenum, bilirubin cannot be excreted; An example is when there are stones in the gallbladder that are embedded in the bile duct.

By BruceBlaus - https://commons.wikimedia.org/wiki/File:Gallstones.png, CC BY-SA 4.0, In these cases, part of the bilirubin stays in the gallbladder and another part returns to the bloodstream.

By not being able to enter the digestive system, there is no other pigment that colored the fecal bolus. For this reason, when bilirubin cannot be excreted rectally, the stool has a light to beige color.

Blood Values ​​in the Patient with Hypocolia

Bilirubin is normally found in the body at basal levels. Normal values ​​for unconjugated or indirect bilirubin are 0.1–0.5 mg / dL, and total bilirubin is 0.3–1 mg / dL.

Clinical signs such as jaundice, coluria, and hypocholia begin to appear when the total bilirubin value reaches 2.5 mg / dL. Values ​​lower than this do not present obvious clinical signs for the patient.

References

1. Elferink, RO (2003). Cholestasis. Gut, 52 Suppl 2 (Suppl 2). Taken from: ncbi.nlm.nih.gov
2. Joseph, A; Samant, H. (2019). Jaundice. StatPearls. Treasure Island (FL). Taken from: ncbi.nlm.nih.gov
3. Stillman, AE. (1990). Jaundice. Clinical Methods: The History, Physical, and Laboratory Examinations. Boston. Taken from: ncbi.nlm.nih.gov
4. Kalakonda A, John S. Physiology, Bilirubin. Treasure Island (FL). Taken from: ncbi.nlm.nih.gov
5. del Valle Díaz, S; Piñera Martínez, M; Medina González, N; Sánchez Vega, J. (2017). Cholestasis: an updated approach. MEDISAN, 21 (7), 876-900. Taken from: scielo.sld.cu