Portal hypertension

Through the portal vein to the liver receives the bulk of blood that drains from the abdominal organs and of greater than 75% of all blood, entering the liver. The remaining 25% of the blood come through the hepatic artery.
In norm in the human body there are natural Porto kavalenya anastomoses in the area pryamokishechnye venous plexus and in the area of the gastro-cardio-esophageal plexus.
In addition to these 2 groups of natural Porto kafelnyh anastomoses, you have a group of links in the system paraumbilical veins. They anastomosis with the veins of the abdominal wall and diaphragm.
Finally, there are 3 groups of anastomoses, located in the retroperitoneal fat: a) communications between veins mesenteric veins and kidneys; b) communications between the top mesenteric and splenic vein, and through them with pronephros Vienna; (C) the anastomosis between the splenic and left renal vein.
Arterioles, owned by hepatic artery, give connecting branches to the portal venules and they formed the sinusoids. Thus it is included the arterial blood into a single system of blood circulation of the liver. It should be noted that 3/4 of hepatic capillaries are in active status and form a reserve of the intrahepatic blood flow.
From the liver blood flowing in the hepatic veins that drain into subphrenic Department of the inferior Vena cava. Using x-ray methods of examination showed the presence of connections between the system liver and portal veins in the form of intrahepatic Porto kafelnyh anastomoses.
The pressure in the large hepatic veins corresponds to a pressure in the inferior Vena cava. The pressure in the small hepatic veins equal to the pressure in the system of portal vein.
Etiology. For the first time the term "portal hypertension" coined in 1928 the English surgeon Archibald McJndoe. In the basis of its development is the obstruction to blood flow through the system of portal vein. It is generally assumed block of a mechanical nature, but certainly there are cases and functional, apparently spastic, origin block this or that Department portal system.
Distinguish:
1) intrahepatic, the most frequent type of the mechanical block portal system;
2) off(up)hepatic type;
3) over(over)hepatic block type;
4) mixed type box; with this type of cirrhosis complicated by the thrombosis of the portal vein or its branches.
Depending on localization of the block portal hypertension may be accompanied by different symptoms and has different etiology.
In the development of the syndrome of portal hypertension intrahepatic of origin can have etiological significance anomalies intrahepatic branch of the portal vein, congenital narrowing of the riverbed of the portal vein, tumors inside the liver, and the most commonly - cirrhosis of the liver (up to 70% according to many authors).
In the development of out(up)hepatic forms of portal hypertension play the role of congenital anomalies of development of the trunk of the portal vein and its branches, cavernous its transformation, congenital obliteration or portal vein stenosis, thrombosis, compression of the veins of the portal system tumors, scars, auxiliary infiltration, periodicially lymphadenitis, primary or secondary gate and door fleboscleros, caused by infectious process or blunt abdominal trauma, splenic or liver arteriovenous fistula.
Because the clinical picture of the block of the trunk of the portal vein and its main branches rather monotonous, it is not always possible to precisely localize where the unit, in the portal or in the splenic vein. So, apparently, right D. M. of Grapes and M. D. Patsiora (1962), which combine patients with portal hypertension, is due out(up)liver unit, regardless of the cause of the blockade and localization of the block in one group "syndrome extrahepatic portal hypertension.
In the development of the syndrome of portal hypertension caused over(over)hepatic localization unit, play the role of the hepatic vein thrombosis syndrome (Budd-Chiari), compression of hepatic or trunk of the inferior Vena cava from outside (for example, when scar contraction holes in this vein in the diaphragm), right ventricular heart failure, chronic constrictive pericarditis.