In adults, the portal vein is an important vessel formed by the splenic vein and the superior mesenteric vein converging behind the pancreas. Blood from abdominal organs such as the stomach, small intestine, spleen, pancreas and colorectum must pass through the portal vein before it can flow to the liver, where nutrients absorbed by the digestive tract can be synthesized into substances necessary for human survival, and where many toxins and wastes produced by the body can be metabolized and detoxified. The normal portal vein pressure is 13-24 cmH2O, with an average of 18 cmH2O. If the portal blood flow is obstructed and the blood is stagnant for various reasons, the pressure in the portal system will exceed the normal value and a series of symptoms will appear, such as splenomegaly and hypersplenism, esophagogastric varices and vomiting of blood, ascites, etc. This is known as portal hypertension.
I. Etiology and classification
The etiology of portal hypertension can be divided into three types: prehepatic, intrahepatic and posthepatic. Intrahepatic type is the most common in our patients, accounting for about 90%.
Prehepatic type: The portal vein itself has problems, such as thrombosis, congenital malformation and external compression, which make the portal vein blood flow poor and the pressure will naturally rise. This type of patient has no liver problems, so the liver function is normal or only mildly damaged, and the treatment effect is best.
Intrahepatic type: problems with the liver, such as cirrhosis of various causes (post-hepatitis, alcoholic, autoimmune, cholestatic), cause blood from the portal vein to overcome a lot of resistance to flow into the liver, so the pressure in the portal vein becomes higher and higher.
Post-hepatic type: such as Budd-Chiari syndrome or constrictive pericarditis, etc. There is also no problem with the liver, but there is a problem with the vascular system behind the liver, so the blood in the liver cannot drain out, which then affects the blood in the portal vein as well, making the pressure in the portal vein rise continuously.
II. Symptoms and Dangers
The vast majority of portal hypertension is caused by liver cirrhosis, and many patients have symptoms such as weakness and loss of appetite, but the most typical clinical symptoms are the following three
(a) Splenomegaly: Since the portal vein collects blood coming from the spleen, the spleen will bruise and swell after poor blood flow in the portal vein, and as a result, the spleen becomes hyperfunctional, i.e., it destroys too many blood cells causing anemia, leukocytosis and thrombocytopenia in patients.
(ii) Upper gastrointestinal bleeding: Similarly, after increased portal vein pressure and poor blood flow, blood from organs in the abdominal cavity bypasses the portal vein and liver and flows away from veins in the fundus and esophagus, thus varices in the lower esophagus are an important manifestation of portal hypertension. These varicose veins are very weak and often rupture due to ulcers or puncture wounds from food causing gastrointestinal hemorrhage.
(iii) Ascites: Patients with cirrhosis are often malnourished and the albumin level in the serum is lower than normal causing generalized edema and ascites. Poor portal venous blood flow leads to gastrointestinal stasis also aggravates the degree of ascites. Tens of thousands of milliliters of ascites can exist in the abdominal cavity of patients in advanced stages, which seriously affects respiratory function and induces hepatorenal syndrome with oliguria or even anuria.
III. Auxiliary examinations and diagnosis
(A) Auxiliary examination
1.Most patients have a history of hepatitis, alcoholism or schistosomiasis. A few patients have a history of unexplained jaundice and may usually be prone to nosebleeds or easy bleeding of gums, chronic diarrhea, bloating, swelling of lower limbs and other abnormal manifestations.
2.If you go to the hospital for a physical examination, you may find jaundice, red palms (hepatic palms), spider moles on the chest and varicose veins in the abdominal wall, an enlarged spleen, and ascites.
3. In order to make a preliminary judgment, the doctor first prescribes routine non-invasive tests, such as routine blood and urine tests, coagulation function, liver function (mainly looking at bilirubin, albumin, transaminases), methemoglobin (screening for liver cancer), checking for hepatitis B or C infection, and fecal hatching test or serum ring egg test for suspected schistosomiasis.
Ultrasound is also commonly used to get a general idea of the size of the liver and spleen, the presence of cirrhosis, ascites and its severity, and to scan the portal vein system for thrombosis, patency of the portal vein, blood flow and direction of blood flow.
5, abdominal enhancement CT scan is the examination which has the value of confirming the diagnosis of portal hypertension, which can clearly observe the diameter of portal vein, the presence or absence of thrombus, the presence or absence of a large number of varices, the degree of liver lesion and the presence or absence of liver cancer, the condition of spleen, the amount of ascites. ct is the key examination which has the function of guiding the next step of treatment.
6.If you want to know whether there are varices in esophagus and gastric fundus and their degree, the simple method is barium X-ray meal, and the high accuracy is to do fiberoptic gastroscopy, which can determine the risk of bleeding at the same time and do the treatment.
7.Measurement of portal vein pressure is the direct evidence to diagnose portal hypertension, invasive measurement is seldom used at present, generally do nuclear heart and liver blood flow ratio (H/L) to indirectly infer portal vein pressure
(B) Differential diagnosis
1. Patients bleeding and vomiting blood or black stool may be bleeding from ruptured esophageal varices caused by portal hypertension, but it is also important to realize that gastric or duodenal ulcer, erosive gastritis, gastric cancer and other diseases can also cause bleeding in the gastrointestinal tract. A detailed review and analysis of the condition, a thorough and complete physical examination and the aforementioned laboratory tests can help in the identification of these diseases.
2. Patients with bleeding anemia, low white blood cells and platelets are mainly identified with various hematologic diseases, such as myelofibrosis or proliferation abnormalities, thrombocytopenic purpura, etc. Usually bone marrow aspiration or biopsy and special laboratory tests in hematology can clarify the diagnosis.
3. There are actually many reasons for patients to have a large amount of ascites, including peritoneal tuberculosis, cardiac insufficiency, a few immune system and kidney diseases, tumors of the abdominal cavity or ovaries, etc. Some cases often require multidisciplinary consultation to confirm the diagnosis.
IV. Treatment methods
For example, the best treatment for all intrahepatic cases is liver transplantation. Once the liver problem is solved, the portal vein will naturally flow and the portal pressure will come down. For patients without liver transplantation, the main goal is to control the progression of liver lesions by transplanting hepatitis virus and reducing the degree of liver fibrosis. The post-hepatic type should be considered in terms of how to open the blood outflow channels of the liver, if it is Buga syndrome, interventional methods or radical surgery for Buga syndrome can be considered, and some cases of constrictive pericarditis can also be solved surgically. The treatment of prehepatic type is less, and the lesion of portal vein itself is difficult to be cured by surgery, and often only symptomatic treatment is available.
(I) Internal treatment
1.General and dietary treatment When the patient with portal hypertension is stable and no other complications are obvious, the comprehensive treatment can be based on the following principles to treat the cause or related factors
(1) Rest: patients with portal hypertension generally do not emphasize bed rest during the period of liver function compensation, and those with mild disease can participate in general work appropriately but should reduce labor time and labor intensity, pay attention to the combination of work and rest, in order not to feel fatigue. Those who are more seriously ill or have recently had complications such as gastrointestinal hemorrhage should stop working to ensure sufficient bed rest and sleep time to prevent fatigue, rest can facilitate the improvement of liver microcirculation to promote liver cell regeneration and repair to reduce liver damage
(2) Diet: Since the entire gastrointestinal function of the patient is affected, high-calorie, easy-to-digest soft food should be given. For patients with chronic liver disease, a proper diet can supplement nutrition, improve liver metabolism, enhance body resistance, promote hepatocyte regeneration and repair, and prevent various complications. In principle, it is advisable to give foods with sufficient calories and rich in various vitamins, which contain not only high sugar, high protein (protein intake should be limited for those with hepatic encephalopathy), appropriate fat and vitamins, but also various inorganic salts and trace elements. Food is mainly soft food, should avoid the risk of bleeding caused by mechanical damage to the esophagogastric mucosa caused by hard and rough food, try to control spicy and irritating food, alcohol is strictly prohibited.
(3) treatment of ascites: the appearance of ascites is a manifestation of impaired liver function to a certain extent, the worse the liver function ascites is more difficult to eliminate, so the treatment of ascites focuses on correcting and restoring liver function. If the patient has more ascites, it is necessary to give supplemental albumin with diuretics to increase the discharge of hydronephrosis, stubborn ascites can sometimes only be released by abdominal puncture to reduce the patient’s discomfort.
2.Drug therapy for lowering portal vein pressure
There are three main categories of drugs used to reduce portal vein pressure.
(1) vasoconstrictor drugs: can directly or indirectly cause visceral vasoconstriction to reduce portal venous blood flow, so as to reduce portal venous pressure and reduce the role of collateral blood flow. Commonly used drugs are posterior pituitary hormone, terlipressin acetate, sestamibiin, santamibiin, aminogest, etc.
(2) Vasodilator drugs: reduce portal pressure by relaxing blood vessels and dilating portal blood vessels or reduce portal pressure by dilating peripheral blood vessels and reducing visceral arterial blood flow. Commonly used drugs include prazosin, phenazopyridine, phentolamine, colistin, and nitroglycerin, cardiac pain, cardiac pain, isoptin, etc.
(3) Other: diuretics such as tachyphylaxis and spironolactone can reduce portal pressure by lowering blood volume and cardiac output, reducing visceral blood flow, and Chinese herbs such as Salvia, Angelica, Chuanxiong and Paeonia can improve liver microcirculation and dilate portal vein to reduce portal pressure.
(B) Treatment of gastrointestinal bleeding
In fact, gastrointestinal hemorrhage is the most dangerous complication of portal hypertension, because there are many varicose veins in esophagus and gastric fundus, and the pressure of the veins is very weak, once rupture, the patient can vomit a lot of blood in a short time, and may even die before seeking medical attention, so how to treat and prevent gastrointestinal hemorrhage is an important part of the treatment of portal hypertension. The first treatment is to save life, including rapid rehydration, blood and plasma transfusion, drugs to reduce portal pressure and hemostatic drugs, while striving to carry out the following treatments
1, endoscopic treatment: With the widespread development of gastroscopy, especially the clinical application of emergency endoscopy, has achieved significant efficacy in the emergency treatment of bleeding cases, and due to the continuous development of endoscopic treatment technology, bleeding can be effectively prevented. Several commonly used methods are as follows.
(1) Sclerotherapy: blocking the blood flow by compressing the vein through submucosal injection of sclerosing agent into the submucosal vein next to the varicose vein to cause fibrosis around the vein. Or sclerotherapy can be done by injecting sclerosing agent into the varicose vein so that thrombus forms in the vein and the vein wall thickens and occludes to achieve hemostasis.
(2)Ligature therapy: special elastic rubber band is applied under direct vision to ligature the varices of esophagus, which causes local ischemic necrosis of mucosa and submucosa and occlusion of veins to stop hemorrhage.
(3) Metal clip hemostasis therapy: under direct vision of endoscopy, the special metal clip will clamp the variceal vein, which can quickly eliminate the variceal vein to control bleeding.
2, three lumen two capsule tube compression hemostasis method: is the traditional treatment of ruptured esophagogastric fundic varices bleeding compression hemostasis method, emergency application of local compression can play a better temporary effect, but easy to bleed again after lifting the compression, recurrence rate up to 50% ~ 60%, but can create conditions for endoscopic, interventional or surgical treatment
3, interventional treatment: the most commonly used is transjugular intrahepatic portal vein stent shunt (TIPSS), the role of this treatment is significant, but the hardware and technical conditions require high, operationally difficult, and the long-term results are not very satisfactory.
4.Surgical treatment
If the non-surgical treatment is not effective, or repeated bleeding, if the patient’s liver function and physical condition can still bear it, surgery should be taken decisively. The main procedures are shunt surgery: the main trunk of portal vein system and its main branches are anastomosed with the vena cava and its main branches, so that the higher pressure portal vein blood is shunted into the vena cava, which is a more ideal method to prevent and control hemorrhage because it can effectively reduce the portal vein pressure, including proximal splenorenal shunt, distal splenorenal shunt, gastric coronary vein-inferior vena cava shunt, superior mesenteric vein-inferior vena cava shunt, splenorenal shunt, and splenorenal shunt. Inferior vena cava shunt, splenic cavity and portal vein shunt, etc.
Flow dissection: generally includes intraluminal esophagogastric fundoplication, peripancreatic vascular dissection, and coronary vein ligation. Emergency surgery is generally available, such as peripancreatic vascular dissection, fundoplication or lower esophageal, cardia and fundoplication, etc. In patients with better conditions, emergency bypass is also feasible. In patients with severe hypersplenism and mild varices, simple splenectomy and filling of the splenic fossa with large omentum can be considered. The current view is to achieve rapid hemostasis with minimal surgical trauma, so that the spleen can be preserved as much as possible and postoperative portal vein thrombosis can be avoided, creating conditions for later liver transplantation.