Cholestasis in the newborn

[Kai]

Cholestasis is a reduction of bile formation or bile flow. As a result, bilirubin backs up into the bloodstream (hyperbilirubinemia), leading to a yellow to yellow-green discoloration of the whites of the eyes and skin called jaundice.

Cholestasis has numerous causes, including infections, metabolic problems, genetic defects, and blockages.
The most common symptoms are jaundice and dark urine.
The diagnosis is made by blood tests, then other blood tests, imaging tests, and sometimes liver biopsy are done to determine the specific cause.
Treatment depends on the cause.

Bilirubin is a yellow substance formed when hemoglobin (the part of red blood cells that carries oxygen) is broken down as part of the normal process of recycling old or damaged red blood cells. Bilirubin is carried in the bloodstream to the liver and processed so that it can be excreted out of the liver as part of bile (the digestive fluid produced by the liver). Bilirubin processing in the liver involves attaching it to another chemical substance in a process called conjugation.

Processed bilirubin in the bile is thus called conjugated bilirubin.
Unprocessed bilirubin is called unconjugated bilirubin.

Bile is transported through the bile ducts into the beginning of the small intestine (duodenum). If bilirubin cannot be processed and excreted by the liver and bile ducts quickly enough, it builds up in the blood (hyperbilirubinemia). The excess bilirubin settles in the skin, the whites of the eyes, and other tissues, causing them to turn yellow (jaundice).
In cholestasis, the liver cells process bilirubin properly, but the excretion of bile is impaired at some point between the liver cells and the duodenum. This results in an increase in conjugated bilirubin in the blood and a decrease in bile delivered to the small intestine.
Another effect of bile not being excreted normally into the small intestine is that digestion is impaired. Bile is important for digestion because it helps the body absorb fats and the fat-soluble vitamins A, D, E, and K. When there is not enough bile in the intestine, fat absorption is impaired, which can lead to vitamin deficiency, inadequate nutrition, and a failure to grow and gain weight.