According to the American Academy of Family Physicians, portal hypertension is an increase in pressure in the portal vein, which is the vein that runs through the liver. The cause of this increase in pressure is typically cirrhosis, or scar tissue in the liver. This scar tissue forms in response to the healing of an injury from liver infection, heavy alcohol use, or other causes. Other causes of portal hypertension include blood clots in the veins of the liver, heart disease, and abnormalities in the portal vein itself.
Pathophysiology
As discussed by the Johns Hopkins Gastroenterology and Hepatology website, portal hypertension occurs when the pressure in the portal venous system is at least 5 mm Hg higher than in the systemic venous system. This typically occurs because scarring in the liver results in a back-up of blood into the portal vein. When blood is unable to flow normally through the portal vein because of increased pressure, other vessels must be used to return blood flow to the heart. These other vessels become swollen and thin. Additionally, blood is not filtered as well and toxins build up in the bloodstream.
Identification
One of the most obvious symptoms of portal hypertension is ascites, or abdominal swelling from the buildup of ascitic fluid. This accumulation of fluid can cause abdominal discomfort and shortness of breath because it can become so large that it pushes up on the diaphragm, making it difficult for the lungs to expand. Additionally, patients may develop dark, tarry stools or notice blood in their vomit if they develop gastrointestinal bleeding from thin blood vessels caused by portal hypertension. Confusion and forgetfulness can be other important signs of encephalopathy caused by portal hypertension. Finally, easy bruising or bleeding can be noted because of low platelets.
Complications
The symptoms of portal hypertension can have significant complications. The buildup of ascitic fluid can become infected, a condition known as "spontaneous bacterial peritonitis." This has to be treated with antibiotics. Additionally, some patients can become so encephalopathic that they become comatose and require mechanical ventilation. Patients are also more susceptible to infection and bleeding because of low blood counts.
Treatment
The only curative treatment for the symptoms of portal hypertension is removing the cause, which in most cases is the cirrhotic liver. For this reason, a liver transplant is typically needed to cure portal hypertension. However, there are treatments for the individual symptoms that can help to relieve the symptoms. For encephalopathy, a medication called lactulose is given to increase the frequency of bowel movements and help to expel the toxins that the liver is unable to process. Medications called beta blockers can help to lower the blood pressure in the portal system and thus reduce the chance of bleeding from thin-walled blood vessels.
Prevention
The best way to prevent the symptoms of portal hypertension is to prevent cirrhosis from developing by getting vaccinated against hepatitis A and B, practicing safe sexual practices with barrier methods for contraception, and by refraining from intravenous drug use. However, there are other causes of cirrhosis that cannot be prevented. Once the symptoms of portal hypertension have developed, screening for thin-walled blood vessels and using medications to help prevent bleeding and infection are helpful. A liver specialist, or hepatologist, helps patients with portal hypertension receive the appropriate screening.
