About Portal Hypertension
Portal hypertension is a condition that affects blood pressure within a system of veins called the portal venous system. Veins directed from the stomach, spleen, intestines, and pancreas merge into the portal vein, which then branches into smaller vessels and travels to the liver. If the vessels of the liver are blocked, blood flow is impaired, causing high pressure in the portal system. When the body detects too much pressure in the portal vein, it tries to compensate by creating new vessels to bypass the liver. These new veins, called varices, are weaker than other veins and prone to rupturing.
Why it is Problematic
Portal hypertension can result in medical emergencies. Portal hypertension is responsible for ascites, fluid buildup in the abdominal wall that causes excessive, visible swelling. Sufferers of ascites may appear pregnant or as though they have a "beer belly" when, in fact, the cause is the presence of ascites.
In order to move around blockages in the liver, toxic blood will take other routes to the heart. This causes varices, a type of varicose vein in the esophagus and stomach that is filled with blood due to high pressure in the portal veins. Esophageal varices are located in the lower esophagus or throat near the stomach, while gastric varices are located in the stomach.
These varices bypass the liver, therefore the toxins and nutrients the liver would normally process can travel into the rest of the bloodstream. Varices can rupture and cause dangerous bleeding.
Causes and Risk Factors
Portal hypertension is caused by blockage in the portal vein in the area of liver. When the blockage occurs before the vein has reached the liver it is called prehepatic. When the blockage occurs inside of the liver it is called hepatic. When the blockage occurs in the vein past the liver, it is called posthepatic.
Blockages occurring in the portal vein before it has reached the liver, or prehepatic blockages, are the most common cause of portal hypertension in children. Cirrhosis is the second most common cause.
Cirrhosis, scarring of the liver, is the most common cause of portal hypertension in adults. Portal hypertension is also caused by thrombosis (clotting of the portal vein). A parasitic infection called schistosomiasis can cause portal hypertension. Sometimes the cause of portal hypertension is unknown.
At the onset of portal hypertension, symptoms may be vague. Cirrhosis patients have a greater chance of developing prime symptoms including:
- Gastrointestinal bleeding that creates dark black tar-like stools or blood in stools
- Vomiting blood due to ruptured varices or hemorrhage
- Ascites (fluid buildup in the abdomen)
- Encephalopathy, confusion, and/or forgetfulness due to poor liver function
- Reduced platelets (blood cells that help form blood clots and infection-fighting white blood cells)
Typically, the specific symptoms of portal hypertension help a doctor to reach a diagnosis. Ascites or dilated veins observed in a physical examination or through lab tests, X-rays, or endoscopic exams assist in proper diagnosis of portal hypertension.
Treatment and Prevention
Often there is no treatment for portal hypertension, but complications can be managed and minimized- especially bleeding from varices. Nutrition, surgery, medication, and radiological treatments may be used to treat or prevent further complications.
Treatment of complications is highly dependent on liver function and the overall severity of symptoms.
Endoscopic therapy is the first course of treatment for bleeding varices. One type of this therapy, banding, is a method by which the blood vessel is blocked with a rubber band.
Sclerotherapy, a method of injecting a solution into bleeding varices to create scar tissue and stop the bleeding, is sometimes used when banding methods cannot be used.
Medication such as non selective beta blockers may be prescribed alone or with endoscopic therapy to decrease varice pressure and reduce the bleeding risks.
Behavioral and lifestyle changes may be required to treat complications associated with portal hypertension. Alcohol and drugs must be completely avoided. Over- the- counter medications and natural/herbal supplements should be taken only under the supervision of a doctor. Nutritional and dietary factors such as reducing protein intake and avoiding salt/sodium are critical components of treatment.
If all other treatments fail, a transvenous intrahepatic portosystemic shunt (TIPS) may be performed. TIPS is a procedure in which a stent (tube) is inserted into the middle of the liver to connect the hepatic vein with the portal vein.
Additionally, a distal splenorenal shunt (DSRS) may be used to connect a vein in the spleen to a vein in the left kidney in order to control bleeding and reduce pressure.