Cholestasis or bile stasis is the backing up of bile within the bile ducts. Bile consists of bilirubin, bile acids and other bile components. In the case of cholestasis, the bile is retained in the bile ducts and cannot drain into the intestine.
The cause of cholestasis can be
- a disorder of bile formation in the liver (bile formation disorder) or
- a disorder of the bile outflow (bile outflow disorder)
be.
In the case of a bile outflow disorder, there is a reduced or absent outflow of bile into the intestine. It is caused mechanically, i.e. the bile ducts are not fully patency. Gallstones or tumors can block the ducts. A bile formation disorder is usually due to chronic liver disease.
On the one hand, cholestasis leads to the accumulated substances in the bile entering the bloodstream. On the other hand, cholestasis leads to a disturbance in the digestion of fat and fat-soluble vitamins in the intestine.
These mechanisms lead to the three characteristic symptoms of cholestasis:
- A yellowing of the skin(jaundice or icterus),
- discoloration of urine and stool (dark urine and light stool) and
- itching (pruritus) all over the body.
In the case of cholestasis, a distinction must be made as to whether the causes of the bile blockage lie inside or outside the liver. There are two different forms of cholestasis based on the causes:
- intrahepatic (non-obstructive) cholestasis and
- extrahepatic (obstructive) cholestasis.
Intrahepatic cholestasis is caused by a disorder of bile formation in the liver cells (hepatocytes).
In the case of extrahepatic cholestasis, mechanical obstructions in the bile ducts prevent the outflow of bile.
Illustration of the bile duct leading into the intestine © lom123 | AdobeStock
Possible causes of intrahepatic (non-obstructive) cholestasis include
In addition, among other things
- Liver tumors,
- side effects of medication,
- hormonal changes during pregnancy and
- an undersupply of oxygen to the liver
can lead to intrahepatic cholestasis.
Extrahepatic (obstructive) cholestasis is caused by mechanical obstructions in the bile ducts. These include, for example
Other possible causes of extrahepatic cholestasis are
- Narrowing of a bile duct,
- scarred retractions and
- inflammation of the bile ducts or the pancreas.
Cholestasis typically manifests itself through
- yellowing of the skin and eyes (jaundice or icterus),
- a brown coloration of the urine (dark urine),
- discoloration of the stool (pale stool) and
- itching (pruritus) all over the body.
These symptoms can vary in severity depending on the duration, extent and form of the bile stasis.
The yellowing of the skin and eyes occurs because the excess bile acids and bile pigments enter the blood. They are normally excreted via the intestines. The excess bilirubin is then deposited in the skin and also on all internal organs.
Cholestasis leads to yellowing of the eyes (jaundice) © Alessandro Grandini | AdobeStock
The brown coloration of the urine is also due to the bilirubin released into the bloodstream during cholestasis. It reaches the kidneys via the blood and is excreted in the urine.
The discoloration of the stool is a consequence of the lack of bilirubin in the intestine. Bile acid is normally needed to break down fats in the intestine. Without bile acid in the intestine, there is a lack of breakdown and absorption of fat and fat-soluble vitamins from food. As a result, the stool becomes discolored and light or pale.
The itching all over the body is caused by the increased concentration and deposition of bile acids in the blood and skin. This activates certain tissue hormones that cause a mild inflammatory reaction in the skin. The itching leads to increased scratching and thus possibly also to skin damage.
Depending on the underlying cause of the cholestasis, other symptoms may also occur. These can include
- colicky abdominal pain,
- nausea,
- vomiting,
- loss of appetite and
- fever
may occur.
Cholestasis is diagnosed on the basis of the symptoms and physical findings as well as by
Based on the symptoms, the doctor determines whether the cholestasis is due to causes inside or outside the liver. The blood test in the laboratory shows how severe the cholestasis is. The liver values and the bilirubin level in the blood are measured for this purpose.
If the results of the blood test indicate cholestasis, an ultrasound examination is usually carried out. This is used for further diagnostics and to clarify the cause. Here, for example
- Dilatations of the bile ducts, such as those caused by gallstones or other drainage obstructions, as well as
- a bulging gallbladder
can be detected.
Cholestasis diagnostics usually also include an ultrasound image © familylifestyle | AdobeStock
Depending on the cause of the cholestasis, further imaging examination methods may be used. Cholangiography, for example, allows X-ray imaging of the bile ducts using a contrast agent. ERCP is an endoscopic X-ray contrast imaging of the bile ducts.
The treatment of biliary obstruction depends on whether it is intrahepatic or extrahepatic cholestasis.
In the case of intrahepatic cholestasis, the treatment consists of treating the triggering factor, i.e. the underlying disease. If the cholestasis was caused by liver cirrhosis, for example, this must be treated. In this case, a liver transplant may be considered. If the cholestasis is caused by certain medications, these must be discontinued.
In the case of extrahepatic cholestasis, it is necessary to remove the mechanical outflow obstructions. This is usually done as part of a surgical procedure, which can be performed either open or endoscopically. Depending on the cause of the extrahepatic cholestasis, this may involve
- stone extraction,
- insertion of a stent or a bile duct end prosthesis in the bile duct or
- a dilatation (widening) of the bile ducts
can be performed.
Regardless of the cause, other treatment methods are also used. They aim to treat and alleviate the symptoms and consequences of cholestasis.
Prolonged cholestasis can lead to vitamin deficiency symptoms such as vitamin K deficiency, vitamin D deficiency and calcium deficiency. Dietary measures and the intake of vitamins K and D as well as calcium are therefore recommended to prevent bone disease.
Colestyramine can also be taken to counteract the itching typical of cholestasis.
