Portal hypertension is an increase in blood pressure within portal venous system. The portal venous system consists of veins merging from stomach, intestines, gall bladder, pancreas and spleen to form portal vein that branches into smaller veins in the liver. The obstruction of portal vein due to any reason causes disruption of blood flow to the liver, thus causing portal hypertension. The portal vein carries blood from various digestive organs to the liver as liver plays an important role in filtration of toxins and other waste material out of the system, and obstruction of portal vein leads to back flow of blood causing ballooning of veins within the esophagus, stomach, umbilicus and rectum area known as varicose veins. Varicose veins carry a greater chance of rupture and bleeding that can cause various complications.
What Are The Causes of Portal Hypertension?
The most common cause of portal hypertension is liver cirrhosis. Liver cirrhosis is the severe scarring of liver due to many reasons, the main reasons being hepatitis, alcohol abuse and nonalcoholic fatty liver disease. The fibrous/scar tissue in liver cirrhosis obstructs the blood flow to the liver, thus causing portal hypertension. Other causes of portal hypertension include thrombus within the portal/hepatic vein, obstruction of veins that carry blood from liver to heart, parasitic infection such as schistosomiasis, focal nodular hyperplasia and other times portal hypertension may be idiopathic.
What Are The Symptoms of Portal Hypertension?
There is a greater chance of developing portal hypertension in an individual with liver cirrhosis. In most instances, portal hypertension is marked with gastrointestinal bleeding, which causes blood in stools known as melena. It might also cause hematemesis due to rupture of esophageal varices. Portal hypertension is also associated with ascites, which is marked by fluid collection in the abdominal cavity and can be associated with bloating, cramps and shortness of breath. Decreased functionality of liver due to poor blood circulation might also lead to encephalopathy causing confusion and forgetfulness.
How is Portal Hypertension Diagnosed?
The diagnosis of portal hypertension is usually based on the presence of signs and symptoms during physical examination, the most common signs being ascites and varices of abdomen and rectum. In the absence of these signs and symptoms, the diagnosis of portal hypertension is generally difficult. Lab tests that include liver function tests are done to check for the functionality of liver. It is followed by imaging such as ultrasound, which shows the flow of blood within the portal vein. The various ultrasounds include bidimensional grey-scale ultrasound, color and power Doppler ultrasound, pulse wave Doppler ultrasound, high frequency grey-scale ultrasound, acoustic radiation force impulse imaging (ARFI), dynamic contrast-enhanced ultrasound and transient elastography. Nowadays, transient elastography (TE) is becoming more popular to detect liver elasticity (stiffness) far more early than other imaging techniques. Transient elastography (FibroScan) is a monodimensional ultrasound that was introduced in market in early 2000s and is currently the most popular non-invasive diagnostic aid for liver cirrhosis. Its limitations include obesity, ascites and operator inexperience. If ultrasound is not conclusive then CT scan can be opted for.
In case of gastrointestinal bleeding, endoscopic examination is done, which uses a thin, flexible tube with a camera attached at one end that allows doctor to examine the internal organs. Portal vein pressure can also be monitored after insertion of a catheter that is attached to a blood pressure monitor and measuring the blood pressure of hepatic vein.
The management of portal hypertension involves lifestyle modifications and treating the increased pressure inside the veins with the help of non-selective beta-blockers (propranolol or nadolol) and/or beta-blockers, which further reduces the risk of bleeding. Ascites is managed with diuretics and restriction of sodium in diet. Variceal bleeding is controlled by banding or sclerotherapy procedure that requires sealing off the bleeders with the help of bands or injection of a blood-clotting solution into the varices to stop bleeding. Acute bleeding can be controlled with transjugular intrahepatic portal-systemic shunt (TIPS).
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