What is portal vein thrombosis (PVT)?
Portal vein thrombosis (PVT) is a blood clot of the portal vein, also known as the hepatic portal vein. This vein allows blood to flow from the intestines to the liver. A PVT blocks this blood flow. Although PVT is treatable, it can be life-threatening.
Blood clots are more likely to form when the blood flows irregularly in the body. While doctors typically don’t know what causes portal vein thrombosis, there are a number of risk factors for developing this condition.
Some of the most common include:
- inflammation of the pancreas
- naval infection from the umbilical cord stump in infants
- polycythemia, or excess red blood cells
- oral contraceptives
- cirrhosis of the liver
- liver disease
- trauma or injury
Other risk factors that can contribute to PVT include pregnancy and surgery. In both cases, the blood is more likely to clot, restricting blood flow to other extremities. In more severe cases, these factors can cause life-threatening complications.
In many cases of PVT, you may show few or no symptoms. Some of the most common symptoms of a less severe clot are:
If you have a more severe case of portal vein thrombosis, you could develop portal hypertension, or high blood pressure within the portal vein. This condition causes splenomegaly, or an enlarged spleen, from pressure interfering with regular blood flow. As the spleen expands, the number of white cells is drastically reduced, increasing the risk of infection. Portal hypertension can also cause varices (abnormally enlarged blood vessels) in the esophagus or stomach that may become prone to bleeding.
Other severe symptoms of portal vein thrombosis include:
The symptoms of PVT are unique, and doctors can often figure out that you have a portal vein blood clot if you have a combination of the following symptoms:
- enlarged spleen
- variceal bleeding
- vomiting blood
- liver infections
There are also a number of tests to help detect the size and danger of your portal vein thrombosis.
1. Doppler ultrasonography
This is a noninvasive test that bounces sound waves off of properly functioning red blood cells. While regular ultrasounds use sound waves to produce images, they cannot show blood flow. Doppler ultrasounds, on the other hand, can use imaging to display blood circulation within the vessels. This can be used to diagnose your portal vein thrombosis and determine how severe it is.
2. CT Scans
Computerized tomography scans, or CT scans, use X-ray imaging and processing to produce images of bones and blood vessels. In order to identify blood clots, doctors will inject a dye in the veins that will present on the CT imaging.
3. MRI of the abdomen
Magnetic resonance imaging (MRI) uses radio waves and magnets to identify:
- irregularities in blood flow
- swelling in the abdomen
- masses on other organs, including the liver
This more invasive procedure is an X-ray test used to produce images of blood flow within an artery or vein. Your doctor will inject a special dye directly into the vein and use an imaging test called fluoroscopy to look at blood circulation within the affected organ and identify blood clots.
Treatment greatly depends on the initial cause of the blood clot. For portal vein thrombosis, treatment recommendations will focus on dissolving the blood clot or preventing growth over a long period of time.
For acute PVT, doctors commonly recommend medication as thrombolytic treatment. These prescription drugs can dissolve blood clots. For gradual clot growth, patients may be prescribed anticoagulant drugs — blood thinners such as heparin — to help prevent recurrent clots and any excess growth.
If you have a more severe case of PVT that is causing your esophagus to bleed, your doctors may also recommend taking beta-blockers. These help reduce pressure in the portal vein and stop the risk for any excess bleeding.
Another prescribed medication your doctor may recommend is ocetrotide. This drug helps to reduce blood flow to the liver and reduces pressure in the abdomen. In order to stop bleeding, this medication may be injected directly into the veins.
If you develop portal vein thrombosis from an infection — specifically for infants — doctors may prescribe antibiotic medication to cure the source. As a result, symptoms from PVT will also end.
Some severe cases of PVT may cause bleeding from variceal veins in the esophagus or stomach. To stop the bleeding, rubber bands are inserted through the mouth into the esophagus to tie off the varicose veins.
Surgical options may be recommended depending on the severity of PVT damage. As a last resort, your doctor may recommend shunt surgery. This procedure involves placing a tube between the portal vein and the hepatic vein in the liver to prevent excess bleeding and to reduce pressures in the veins.
In some cases of severe liver damage, your doctor may need to perform a liver transplant.
Portal vein thrombosis is a serious condition. If caught early, PVT can be treatable with noninvasive procedures and treatment. If you begin experiencing irregular symptoms or discomfort, visit a healthcare professional immediately.