Introduction:
The portal vein is the main vessel of the portal venous system (PVS). This system drains the blood from the gastrointestinal tract, pancreas, gallbladder, and spleen to the liver. The hepatic portal vein is about 8 cm long in adults and resides in the upper right quadrant of the abdomen, originating behind the neck of the pancreas. The portal veins drain almost all the blood from the GI (gastrointestinal tract) and empty them into the liver. The exchange of this nutrient-rich blood between the gut and the liver is known as portal circulation.
What Is Portal Vein Obstruction?
This condition is also known as Budd-Chiari syndrome. Narrowing, blockage, or obstruction due to a blood clot in the portal vein is termed portal vein obstruction. Portal vein is the main communication between the intestines and the liver. If a portal vein blockage is not treated at the right time, this may result in a life-threatening condition. It may even lead to liver cirrhosis. Portal vein obstruction can also occur as a primarily vascular disorder in the absence of the diseased condition.
What Are the Signs and Symptoms of Portal Vein Obstruction?
Portal vein obstruction may show few or no symptoms. Some of its manifestations are:
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Severe abdominal pain.
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Swelling in the abdomen due to excess abdominal fluid.
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Abdominal bleeding.
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Fever and chills.
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Enlarged and tender liver.
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Swelling of legs.
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Fatigue (tiredness).
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In severe conditions, the obstruction may cause high pressure in the vein, causing portal hypertension.
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Splenomegaly (enlarged spleen) occurs due to pressure interfering with blood flow.
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There is a reduction in WBC (white blood cells) count due to an enlarged spleen.
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Portal hypertension may also lead to varicose veins.
Severe symptoms include:
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Intense liver pain.
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Yellowing of the skin, mucous membrane, and whites of the eye is called jaundice.
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Varices and gastric bleeding.
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Spiking fevers.
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Tarry or blood stools, foul-smelling stools.
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Liver failure (a condition where normal liver functioning stops).
What Are the Causes of Portal Vein Obstruction?
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Adults with cirrhosis are more common to get portal vein obstruction because blood flow through the severely scarred liver is slow and more blood may clot.
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Common causes differ in the various age group, such as:
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In newborns - Infection of the umbilical cord (naval cord).
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Older Children - Appendicitis infection can spread through the portal vein and cause the formation of blood clots.
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Adults - Myeloproliferative disease, more red blood cells (polycythemia), thrombocytopenia (the body produces more platelets), sickle cell disease (sickle-shaped red blood cell) can lead to portal vein obstruction.
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In certain types of cancers like liver, kidney, or adrenal gland; cirrhosis, and injury.
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Other disorders that can make blood more likely to clot are:
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Surgery.
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Pregnancy.
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Several conditions combine to cause a blockage.
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Most of the time, for about one-third of people, the cause is unknown.
How Is Portal Vein Obstruction Diagnosed?
There are several tests to detect portal vein obstruction and its size. They are as follows:
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Doppler Ultrasound: It is a noninvasive test that bounces sound waves of properly functioning red blood cells. Normally, ultrasound uses sound waves to produce images, but they cannot show blood flow. Doppler ultrasound can use imaging to display blood circulation. This can help diagnose portal vein obstruction and its severity.
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CT Scans (computed tomography)- Use X-ray imaging and processing to produce images of vessels and bones. Doctors will inject dye in the veins that will present in CT imaging; thus, identification of present blood clots can be made.
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MRI Abdomen (magnetic resonance imaging): This technique uses a large magnet and radio waves to create an image. This test can help to identify irregularity in blood flow, blood circulation, masses of organs, including the liver, and swelling in the abdomen. This is an important test in the identification of tumors and other resembling body tissues.
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Angiography: It is a more invasive procedure. In this test, an X-ray is used to produce images of the blood flow of the artery and vein. The health care provider may inject a dye directly into the vein and use an imaging test called fluoroscopy to check the blood circulation to the affected organ, and for the identification of blood clots and blockage.
What Is the Treatment Provided for the Obstruction of Portal Vein?
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Treatment of this condition mainly depends on the cause of the blood clot. The main focus is on dissolving the blood clot or preventing growth over a long period.
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In acute conditions, healthcare providers may recommend medications such as thrombolytic treatment. These drugs can dissolve blood clots.
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In gradual clot growth, healthcare providers may prescribe anticoagulant drugs - blood thinners like Heparin to prevent recurrent clots and growth of blood clots.
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In severe cases where the varices start bleeding, doctors may recommend taking beta-blockers, which reduce pressure in the vein and, in turn, will reduce bleeding.
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Octreotide is recommended as it is a drug that helps to restrict the blood flow to the liver and pressure in the abdomen. This drug can be directly injected into the veins to stop the bleeding due to increased pressure.
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In case of infection, especially in infants, doctors may provide antibiotic therapy to cure the cause.
Other procedures used to treat portal vein obstruction are:
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Banding: In severe cases, there is excess bleeding of veins in the esophagus and stomach. In order to stop the bleeding, rubber bands are used; they are inserted through the mouth to the esophagus to tie off the varicose veins.
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Surgery: Depending on the severity, shunt surgery may be recommended. This procedure involves placing a tube between the two veins; one is the portal vein, and the other is the hepatic vein in the liver, in order to prevent excess bleeding and blood loss that occurs due to increased pressure. This in turn will reduce the pressure in the vein. The procedure is termed TIPS(transjugular intrahepatic shunt). This reroutes the blood flow in the liver and reduces pressure.
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Percutaneous Transluminal Angioplasty: In this method, a catheter is inserted through the skin and blood vessels and is guided to the area where the clot is present; when it reaches the clot, the balloon is inflated to widen the vein. The stent is placed at the site to keep the vein open.
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In extreme cases of liver damage, liver transplantation can be performed.
Conclusion:
Portal vein obstruction is a common complication of the liver disorder that is seen in several metabolic and autoimmune diseases. It is a life-threatening condition. If the disorder is left untreated, it may result fatal. Children with portal vein thrombosis should immediately be referred to the tertiary care center. Early treatment with anticoagulants and TIPS may lead to more chances of survival. Survival improves with liver transplantation in severe cases. An individual having partially blocked veins can live longer, but the life expectancy in each person is different from others.