Portal hypertension: causes

The main causes of portal hypertension:

Prehepatic (subhepatic) portal hypertension.

1. Increased portal venous blood flow:
   1. arteriovenous fistula;
   2. Splenomegaly, not associated with liver disease;
   3. cavernomatosis of the portal vein.
2. Thrombosis or occlusion of portal or splenic veins.

Intrahepatic portal hypertension

1. Diseases of the liver.
   1. Sharp:
      1. alcoholic hepatitis;
      2. alcoholic fatty liver;
      3. fulminant viral hepatitis.
   2. Chronic:
      1. alcoholic liver disease;
      2. chronic active hepatitis;
      3. primary biliary cirrhosis;
      4. viral cirrhosis;
      5. Wilson-Konovalov's disease;
      6. hemochromatosis;
      7. insufficiency of alpha1-antitrypsin;
      8. cryptogenic cirrhosis;
      9. idiopathic portal hypertension;
      10. liver diseases caused by arsenic, vinyl chloride, copper salts;
      11. congenital fibrosis of the liver;
      12. schistosomiasis;
      13. sarcoidosis;
      14. obliteration of intrahepatic branches of the hepatic veins, associated with the treatment with cytostatics;
      15. metastatic carcinoma;
      16. nodular regenerative hyperplasia of the liver;
      17. focal nodular hyperplasia.

Post-hepatic portal hypertension

1. Diseases of the hepatic venules and veins, inferior vena cava:
   1. congenital membranous infection of the inferior vena cava;
   2. vein-occlusive disease;
   3. thrombosis of hepatic veins (illness and Badd-Chiari syndrome);
   4. thrombosis of the inferior vena cava;
   5. defects in the development of the inferior vena cava;
   6. tumor compression of the inferior vena cava and hepatic vein.
2. Heart Diseases:
   1. cardiomyopathy;
   2. heart disease with valve damage;
   3. constrictive pericarditis.

Infections

In newborns, the cause of extrahepatic presynusoidal hypertension may be omphalitis, including that caused by catheterization of the umbilical vein. The infection spreads through the umbilical vein to the left branch of the portal vein, and then to its main trunk. The children of older age are the cause of acute appendicitis and peritonitis.

Occlusion of the portal vein is especially common in India, accounting for 20-30% of all cases of bleeding from varicose veins. In newborns, its cause may be dehydration and infection.

Obstruction of the portal vein can develop with nonspecific ulcerative colitis and Crohn's disease.

It can also be a complication of biliary tract infection, for example, as a result of cholelithiasis or primary sclerosing cholangitis.

Surgical interventions

Obstruction of the portal and splenic veins often develops after splenectomy, especially if the platelet count was normal before the operation. Thrombosis spreads from the spleen vein to the main portal portal shaft. Especially often it develops with myeloid metaplasia. A similar sequence of events is observed with thrombosis of the surgically formed portosystemic shunt.

Thrombosis of the portal vein can develop as a complication of large and complex operations on the liver and biliary tract, for example, when removing stricture or when removing the choledocha cyst.

Injuries

Damage to the portal vein is sometimes observed with car injuries or penetrating stab wounds. Breakage of the portal vein in 50% of cases leads to death, the only way to stop bleeding is vein ligation.

Conditions accompanied by increased thrombus formation

In adults, the state of hypercoagulation often causes thrombosis of the portal vein. More often it is observed in myeloproliferative diseases, which can occur latently. At autopsy macroscopically and histologically often reveal thrombotic changes in patients suffering from portal hypertension and myeloproliferative disease. Thrombosis of the portal vein is accompanied by ascites and varicose veins of the esophagus.

Thrombosis of the portal vein can complicate the course of congenital insufficiency of C-protein.

Invasion and tumor compression

A classic example of a tumor that can germinate into the portal vein or squeeze it is hepatocellular carcinoma. The portal portal block can also cause pancreatic cancer (usually its body) or other vein-adjacent lesions. In chronic pancreatitis, the spleen vein is often obstructed, the portal vein is rarely affected (5.6%).

Congenital anomalies

Possible congenital obstruction of any area of the right and left vitelline veins, from which the portal vein is formed. The portal vein can be absent altogether, and the blood from the internal organs flows into the central veins, mainly into the inferior vena cava. Venous collaterals are not formed in the portal of the liver.

Congenital anomalies of the portal vein are usually combined with other congenital malformations.

Cirrhosis of the liver

Cirrhosis of the liver is very rarely complicated by portal vein thrombosis. The most common cause is hepatocellular carcinoma, which develops against cirrhosis. Another mechanism of obstruction of the portal vein is thrombocytosis after splenectomy. The parietal thrombi detected in the lumen of the portal vein during autopsy appear to be formed in the terminal state. There is a danger of overdiagnosis of thrombosis, because with visualization methods of examination, the portal vein is sometimes not filled, which is associated with the redistribution of blood into large collaterals or into an enlarged spleen.

Other reasons

In very rare cases, portal vein thrombosis can be associated with pregnancy, as well as with prolonged intake of oral contraceptives, especially older women.

The portal vein block can be associated with systemic venous disease, especially with migrating thrombophlebitis.

With retroperitoneal fibrosis, dense fibrous tissue can press the portal vein.

Unknown reasons

Approximately half of the patients after a thorough examination cause the obstruction of the portal vein remains unknown. Some of them identify concomitant autoimmune diseases, for example hypothyroidism, diabetes mellitus, pernicious anemia, dermatomyositis, rheumatoid arthritis. In some cases, obstruction develops after undiagnosed infections of the abdominal organs, for example after appendicitis or diverticulitis. 

1. Sharp:
   1. alcoholic hepatitis;
   2. alcoholic fatty liver;
   3. fulminant viral hepatitis.
2. Chronic:
   1. alcoholic liver disease;
   2. chronic active hepatitis;
   3. primary biliary cirrhosis;
   4. viral cirrhosis;
   5. Wilson-Konovalov's disease;
   6. hemochromatosis;
   7. insufficiency of alpha1-antitrypsin;
   8. cryptogenic cirrhosis;
   9. idiopathic portal hypertension;
   10. liver diseases caused by arsenic, vinyl chloride, copper salts;
   11. congenital fibrosis of the liver;
   12. schistosomiasis;
   13. sarcoidosis;
   14. obliteration of intrahepatic branches of the hepatic veins, associated with the treatment with cytostatics;
   15. metastatic carcinoma;
   16. nodular regenerative hyperplasia of the liver;
   17. focal nodular hyperplasia.
3. Diseases of the hepatic venules and veins, inferior vena cava:
   1. congenital membranous infection of the inferior vena cava;
   2. vein-occlusive disease;
   3. thrombosis of hepatic veins (illness and Badd-Chiari syndrome);
   4. thrombosis of the inferior vena cava;
   5. defects in the development of the inferior vena cava;
   6. tumor compression of the inferior vena cava and hepatic vein.
4. Heart Diseases:
   1. cardiomyopathy;
   2. heart disease with valve damage;
   3. constrictive pericarditis.

[1], [2], [3], [4]