Our blood vessels are extensive. They are so extensive, in fact, that if you place them end-to-end, they can traverse the whole globe. Our body is designed this way to be able to deliver nutrients and oxygen to each cell of the body efficiently. Our blood vessels are formed of arteries, veins, and the connection between them are the capillaries.
Our circulatory system is formed of the heart and the blood vessels, but it is also divided into two main divisions, the systemic and the portal one. A portal venous system is that which forms a closed loop without the heart. It is found in our gastrointestinal system and in our brain.
The system that involves our gastrointestinal system is called the hepatic portal system. It serves a vital function, which is to deliver nutrients to the liver first for detoxification and metabolism before letting them into the systemic circulation. Without this vital function, many toxins can go into the systemic circulation, damaging the brain.
What is portal hypertension, and how does it occur?
Portal hypertension is the increased blood pressure within the portal venous system. The portal venous system is a low-pressure one and is not directly connected to a strong pump like the heart. Changes of pressure within this system is related to meals and it occurs normally throughout the day. However, some diseases can cause portal hypertension as a side effect of their occurrence, and they include:
- Liver cirrhosis: Liver cirrhosis is perhaps the most common cause of portal hypertension worldwide. It is not a disease, but a manifestation of liver damage that can occur due to a variety of diseases including alcoholic liver disease and viral hepatitis. It is usually the end stage of hepatitis B and C infections.
- Thrombosis of the portal vein or hepatic veins: The hepatic portal system is formed of a system of veins that are connected to each other. An occlusion of any vein can cause blood to accumulate behind the site of occlusion. This usually occurs in case of a blood clot and can cause portal hypertension.
- Bilharziasis: Bilharziasis is a parasitic infection by a parasite called Schistosomiasis. It is now very rare and has been eradicated in many countries. It resembles cirrhosis, but liver functions are maintained.
Regardless of the cause, portal hypertension remains the main cause of esophageal varices. Varices form as shunts or shortcuts to help reduce the pressure within the portal systems by shunting blood to the systemic system. They are found normally in our bodies as safety valves. Ones that are not supposed to be used.