 Portal Hypertension
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Portal hypertension is abnormally high blood pressure in the portal vein, the primary vein which brings blood from the intestine to the liver. When this vein clots or when the liver develops scar tissue from disease and compresses the vein, the blood pressure in the vein goes up and portal hypertension develops.
The liver normally filters blood from the abdominal organs. Portal hypertension can prohibit the liver from doing its job by causing the growth of new blood vessels, called collaterals, that connect blood flow from the intestine to the general circulation, bypassing the liver. When this occurs, substances that are normally removed by the liver pass into general circulation. If not treated, portal hypertension can be progressive and cause serious complications.
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The liver is located in the upper right-hand portion of the abdominal cavity, beneath the diaphragm and on top of the stomach, right kidney, and intestines. The liver, is a dark reddish-brown organ that weighs about three pounds and has multiple functions. The liver regulates most chemical levels in the blood and excretes a product called bile, which helps to break down fats, preparing them for further digestion and absorption. All of the blood leaving the stomach and intestines passes through the liver. The liver processes this blood and breaks down the nutrients and drugs in the blood into forms that are easier to use for the rest of the body. More than 500 vital functions have been identified with the liver. For more information on the liver, see How the Liver Works.
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Portal hypertension can occur in children with any type of chronic liver disease. It occurs when liver disease leads to obstruction of blood flow through the portal vein.
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The symptoms of portal hypertension may include:
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- A distended abdominal cavity
- Bleeding of the varicose veins at the lower end of the esophagus and in the stomach lining
- Discomfort
- Shortness of breath
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Symptoms of portal hypertension may resemble other liver conditions or medical problems. Always consult your child's physician for a diagnosis.
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Symptoms that suggest portal hypertension may be evaluated by your child's physician with the following diagnostic procedures in addition to taking a complete medical history and performing a physicial examination
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- Abdominal Ultrasound: A diagnostic imaging technique which uses high-frequency sound waves and a computer to create images of blood vessels, tissues and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels. Gel is applied to the area of the body being studied, such as the abdomen, and a wand called a transducer is placed on the skin. The transducer sends sound waves into the body that bounce off organs and return to the ultrasound machine, producing an image on the monitor. A picture or video tape of the test is also made so it can be reviewed in the future
- Doppler Flow Study - A type of ultrasound that uses sound waves to measure the flow of blood through a blood vessel. Waveforms of the blood flow are shown on the ultrasound screen. Doppler flow studies may be used to assess blood flow throughout the portal venous system. Doppler flow is sometimes called Doppler velocimetry.
- Angiogram - Dye is injected into the blood vascular system and x-rays are performed to trace the course of the blood vessels.
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The treatment of portal hypertension may depend on a combination of the following:
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- the extent of liver damage
- the extent of portal hypertension
- the overall health of the child and medical history
- the opinion of the physicians involved in the child's care
- parental opinion and preference
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If there is extensive bleeding, portal hypertension is treated emergently with a combination of fluid resuscitation, replacement of red blood cells and medication to control the bleeding. A long-term strategy is then planned to prevent bleeding in the future. Depending on the extent of damage to the liver, this may include liver transplanation.
If portal hypertension is accompanied by good liver function, with good production of all necessary proteins, an operation called portal vein shunting can be performed for long-term management. During this operation, the surgical connection between the portal vein or its branches and the vena cava (vein carring blood from the lower extremities and kidneys to the heart) or its branches is created. This allows blood from the portal vein to be redirected into the vena cava, resolving the portal hypertension.
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The long-term outlook for a child with portal hypertension depends heavily on the underlying cause of liver disease and the extent of liver damage. Many children with liver disease eventually must undergo liver transplanation. But if the liver is functioning well, portal hypertension can usually be managed successfully and may even improve over time as more collaterals form to bypass the occluded portal vein.
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