Synonyms in a broader sense
Medical: Portals hypertension liver, cirrhosis of the liver
Definition Portal Vein Hypertension
Portal hypertension is the chronically increased pressure in the portal vein (vena portae) above a certain threshold. This pressure increase is caused by an obstruction of the blood flow through the portal vein or the liver, which can have various causes. In 80% of cases, however, cirrhosis of the liver is the cause, which in turn is mostly caused by alcohol abuse.
Cause of the disease
The portal vein (vena portae) transports venous blood from the digestive organs of the gastrointestinal tract to the liver. This venous blood is low in oxygen, but (after meals) contains all the substances (nutrients, medication, etc.) that are absorbed.
The liver now has the task of storing or transforming the nutrients and disposing of toxic substances. If pathological processes (e.g. cirrhosis of the liver, viral hepatitis, thrombosis) obstruct the flow of blood through the liver, the blood inevitably congests in the blood vessels supplying it, which leads to an increase in blood pressure (high blood pressure). This phenomenon is known as portal hypertension.
The cause is not always a disease of the liver. In so-called congested liver, the blood backs up in the liver because, in the context of right heart failure, the blood cannot be pumped into the pulmonary circulation and therefore backs up into the liver. In this case, heart failure is therefore responsible for the increase in portal vein pressure.
Although two different vessels supply blood to the liver (arteria hepatica with oxygen from the aorta and vena portae with nutrients from the gastrointestinal tract), only the pressure increase in the portal vein is associated with complications, since in the portal vein, as in all veins, blood pressure is much lower than in arteries, and therefore slight differences in pressure can have a much greater effect. Due to the congestion and the subsequent increase in pressure in the portal vein, the direction of blood flow is reversed. The blood looks for a different flow path to reach the right heart.
There are smaller connections between the entry area of the portal vein and other veins that lead directly into the right heart (the so-called porto-caval anastomoses). As in the case of a traffic jam on the road, these alternative routes are not designed to cope with the increased stress and therefore typical complications occur.
- HemorrhoidsA bypass route leads through the venous plexus of the anus.
This venous plexus flows into the portal vein as well as via the inferior vena cava directly into the right heart. If the portal vein hypertension causes chronically too much blood to flow through the plexus of small veins, they expand excessively. They then protrude into the intestinal canal and burst easily (hemorrhoids).
This is very painful for the patient, who loses venous blood (dark red color). There is another, more common form of hemorrhoids, which can develop due to a weakness of connective tissue and veins. In this case, however, it is arterial, i.e. oxygen-rich blood, which has a light red color.
- Esophageal varices bleedingThe veins of the esophagus, connected via the venous plexus of the stomach, also form a possible alternative route.
Here, too, chronic overload leads to swelling of the veins, which gradually tear. The tearing is promoted by the strong mobility of the esophageal wall during the transport of food into the stomach. Due to the injury of the vessels, the blood is lost via the esophagus and thus via the digestive tract.
This is life-threatening for the patient, as he rarely notices that he is bleeding here. On the long way through the intestines the blood coagulates, becomes black due to the stomach acid and mixes with the stool. As a result, blood is lost unnoticed (occult bleeding), often in large quantities.
The patient develops anemia, the cause of which is not so easy to find. An important method is the use of a hemoccult test strip. The patient must place a little stool on the test strip. If there is coagulated blood and thus the blood pigment hemoglobin in the stool, this can be seen on the test strip.
