While liver disease is rare in children, portal hypertension is even less common. For this reason, few centers are able to adequately manage the care of children with this serious condition. Over the next few pages we will introduce you to the basics of portal hypertension, its causes, signs and symptoms, and how the physicians in the Center for Childhood Liver Disease at Boston Children's Hospital care for children with portal hypertension.
The liver is a large organ (the second largest in the body) responsible for processing nutrients from our food and medications in ways that allow the rest of the body to make use of them. It also acts as a big filter for the bloodstream, removing poisons and toxins as well as byproducts made by our cells and tissues. The liver helps to control our blood sugar and cholesterol, and it produces chemicals that help our blood to clot.
The liver is truly unique in how it receives its blood supply. Nearly every tissue and organ in the body receives nourishment and oxygen from blood delivered through an artery, which carry blood under high pressure due to the heart’s pumping action. The liver, however, is the only organ to receive the majority of its blood supply through a large vein. Called the portal vein, this vein carries blood to the liver from the intestines and the spleen.
Why would the liver work this way? The pressure in veins, including the portal vein, is much lower than in arteries. The reduced pressure allows blood to percolate through the liver and gives the liver’s cells the time they need to do their work.
Obstruction of the portal vein – caused primarily by clots in or narrowing of the vein before it reaches the liver, cirrhosis, or high pressure in the veins that drain the liver into the heart – can cause the pressure in the vein to build up, much as blocking the end of a hose causes the pressure in the hose to climb. Increased portal vein pressure – known medically as portal hypertension – causes blood to back up in the organs that send blood to the liver. The body tries to relieve the pressure by generating new blood vessels that bypass the blockage, but such vessels are often weak and twisted, and tend to bleed easily. These vessels, called varices, may also bypass the liver itself, allowing toxins and nutrients to travel through the bloodstream unprocessed.
How Boston Children's Hospital approaches portal hypertension
The weak blood vessels produced by the body in response to portal hypertension put a child at risk for gastrointestinal bleeding (bleeding into the intestine that causes vomiting of blood and/or passage of blood from the rectum). The major goals of the physicians, nurses, and staff in the Center for Childhood Liver Disease in treating children with portal hypertension are to reduce that risk and, ideally, to reduce the increased blood pressure in the portal vein by identifying its root cause. At every step, our specialists endeavor to provide compassionate care that respects the values of each family and addresses their hopes and concerns for their child’s present and future health.