First, Etiology

　　The main cause of portal hypertension in childhood is the embolism of the portal vein and splenic vein. Splenic vein thrombosis may be related to neonatal umbilical inflammation, neonatal sepsis, complications of umbilical vein catheterization, portal vein cavernoma, congenital splenic vascular malformation, abdominal mass compression, and other factors. Portal hypertension can be divided into extrahepatic and intraportal types.

　　1. Extrahepatic type portal hypertension

　　Congenital portal vein malformation, cavernous disease, portal vein obstruction, and thrombosis can all cause portal hypertension. The splenic vein can be obstructed due to congenital valve malformation, or due to neonatal umbilical inflammation, sepsis, or umbilical vein catheterization, leading to splenic vein inflammation and thrombosis.

　　2. Intrahepatic type portal hypertension

　　Seen in chronic hepatitis, congenital bile duct stenosis or atresia, schistosomiasis, galactosemia, hepatolenticular degeneration (Wilson's disease), pancreatic cystic degeneration.

　　Second, Pathogenesis

　　The splenic vein belongs to the portal venous system. In normal people, 70% of the splenic vein blood flows into the portal vein. If there is obstruction in the portal vein, the backflow of the spleen can be obstructed, leading to congestive splenomegaly. When the cause of congestion is removed, the enlarged spleen can shrink. In late cases, due to the proliferation of fibrous tissue and reticuloendothelial tissue, even if the cause is removed, the splenomegaly does not shrink significantly. It is currently believed that this sign is not an independent disease, but a group of symptoms caused by chronic portal hypertension or liver cirrhosis, including high degree of splenomegaly, anemia, and splenic hyperfunction.

　　Causes esophageal varices, rupture, and bleeding. In the late stage, symptoms of liver cirrhosis often occur, such as ascites, jaundice, severe malnutrition, lower limb edema, and subcutaneous venous dilatation (collateral circulation) in the chest and abdomen, as well as hematemesis and melena. Ascites generally does not occur in extrahepatic portal hypertension. Splenomegaly is the main sign of pediatric portal hypertension. The spleen is usually moderately enlarged, and its hardness mainly depends on the duration of portal hypertension. After portal hypertension occurs, collateral circulation is formed to ensure blood returns to the heart. Upper collateral circulation forms esophageal varices at the lower segment and submucosal varices at the fundus of the stomach, while lower collateral circulation forms middle and lower hemorrhoidal varices. These varices are frequently abraded by food and fecal masses, easily rupturing and causing hematemesis and melena.

　　First, portal hypertension

　　1. Extrahepatic type portal hypertension

　　The onset of upper gastrointestinal symptoms (vomiting blood and black stools) is earlier in this disease; ascites is less common and easy to regress; significant splenomegaly with hypersplenism, neonatal sepsis, umbilical disease history, or umbilical vein catheterization history, without a history of hepatitis.

　　2. Intrahepatic type portal hypertension

　　Common in chronic hepatitis cirrhosis, post-necrotic cirrhosis, advanced schistosomiasis cirrhosis, congenital bile duct stenosis, etc. The appearance of vomiting blood and hematochezia, and other gastrointestinal symptoms is later than that of extrahepatic type. The disease is prevalent between 2～12 years old. Gastrointestinal bleeding is often accompanied by malnutrition, and there is often refractory ascites, abnormal liver function with coagulation dysfunction, liver enlargement or shrinkage, hardness can be palpated, nodules; marked splenomegaly is often accompanied by hypersplenism, portal vein angiography is the main method of diagnosis, individual cases with difficult diagnosis need to be confirmed by laparotomy.

　　Second, chronic congestive heart failure

　　More common in school-age children, long-term venous congestion can lead to cardiogenic liver cirrhosis, which can cause splenomegaly, but it is rare.

　　Third, restrictive pericarditis

　　85% of cases with chronic restrictive pericarditis have splenomegaly, mostly mild.

　　Fourth, portal vein thrombosis

　　Extremely rare,可分为急性和慢性两型，两型都有脾肿大，急性型常继发于脾切除术，门静脉手术，门静脉感染或创伤之后，其主要临床表现为急性腹痛，腹胀，呕吐，呕血和便血，慢性门静脉血栓形成比急性者多见，常见于肝硬化，其次为肝癌或腹腔内其他脏器压迫，侵蚀门静脉，患儿可有腹水，脾肿大和脾功能亢进，本病肝脏极少肿大，以脾肿大为明显，此点可与肝静脉阻塞相区别，脾门静脉造影是诊断本病的主要方法，部分病人经手术探查方能确诊。

　　Fifth, hepatic venous obstruction syndrome

　　Rare in clinical practice, only a few cases have been reported in China, mostly caused by thrombosis, primary cases are rare, mostly secondary, divided into acute and chronic types. The acute type is mainly characterized by abdominal pain, mild jaundice, liver enlargement, ascites. The chronic type, in addition to abdominal pain, liver enlargement, and dyspepsia, also has splenomegaly, ascites, and inferior vena cava angiography is used for diagnosis. The prognosis of this disease is poor.

　　The etiology of this condition is diverse, including intrahepatic and extrahepatic factors. For the purpose of prognosis and treatment, it is necessary to further investigate the etiology and differentiate between intrahepatic and extrahepatic conditions. Preventing primary liver disease is essential to prevent splenomegaly.

　　1. Blood routine examination

　　Present with varying degrees of anemia, leukopenia, normal or slightly reduced platelets, poor clot retraction, and positive brachial cuff test. Typical cases show significant leukopenia. In the early stages of the disease, anemia is normochromic, which turns to microcytic hypochromic after multiple hemorrhages. After hemorrhage, reticulocytes and leukocytes can temporarily increase. The larger the spleen, the lower the leukocyte count, usually between (1.5～4)×10^9/L.

　　2. Bone marrow examination

　　In the early stage, there are no abnormal changes, and sometimes hyperplasia is present, with an increase in nucleated red blood cells and megakaryocytes, and cell maturation disorders are observed. In the middle stage, the maturation of granulocytes and megakaryocytes may be limited, and in the late stage, the maturation of red blood cells is affected.

　　3. Liver function tests

　　Before liver cirrhosis, liver function tests are mostly normal.

　　4. Changes in coagulation factors

　　In the early stage, there is only splenomegaly without liver dysfunction, and there is no significant difference in various coagulation factors. In the late stage of liver cirrhosis, various coagulation factors are significantly different from normal controls.

　　5. X-ray and ultrasonic examination of the spleen

　　If the spleen cannot be palpated under the costal arch, X-ray and ultrasonic examination can be used to determine the size, location, and nature of the spleen, and to determine whether the mass is the spleen. At the same time, ultrasonic examination is valuable for exploring the size of the spleen and the presence and amount of ascites.

　　6. Esophageal and gastrointestinal barium meal examination, renal pelvis angiography

　　Esophageal varices can be observed through esophageal barium meal examination to understand whether there is portal hypertension. Through gastrointestinal barium meal examination, renal pelvis angiography, and other methods, it is helpful to differentiate the nature of abdominal masses.

　　Diet should be low in fat, high in protein, high in vitamins, and easy to digest, and it is important to maintain regularity, quantity, and moderation. More fresh vegetables and fruits should be eaten, and appropriate amounts of carbohydrates, eggs, fish, lean meat, etc., should be consumed.

　　1. Treatment

　　In cases with predominant hypersplenism, splenectomy often results in good effects, with blood counts quickly returning to normal in a short period of time, ultimately achieving recovery. In cases with predominant portal hypertension, splenorenal venous anastomosis should be performed simultaneously. In cases with predominant liver cirrhosis, as the liver cells have been severely damaged, surgical treatment is of no benefit, and supportive therapy should be adopted, including high-protein, high-carbohydrate diets, a variety of vitamins, iron or liver preparations, which are effective for anemia. Blood transfusion may be necessary if indicated. If there is also a tendency to bleed, fresh blood transfusion is recommended. Edema should be treated with diuretics. For patients with esophageal varices, vasopressin 0.1-0.2U/min can be injected intravenously, which can cause the contraction of visceral arteries and hepatic arteries, thereby temporarily reducing portal pressure to stop bleeding.

　　1. Splenectomy surgery

　　When the disease presents with severe hypersplenism, consideration should be given to splenectomy. The prognosis after surgery varies depending on the location of the obstruction and the surgical method. If the obstruction is in the splenic vein, the postoperative effect is good, and recovery can be achieved. In cases with predominant intrahepatic or portal vein lesions, bleeding may still occur after splenectomy, but the phenomenon of hypersplenism can be alleviated.

　　2. Shunt surgery

　　In order to alleviate portal hypertension, especially in patients with extrahepatic portal hypertension and esophageal varices, surgical treatment should be considered. Directly shunting the high-pressure portal vein blood flow into the lower pressure inferior vena cava system (portosystemic shunt) is actually an effective method to reduce portal pressure. In the early stage of the disease, liver function is normal. If the shunt operation is successful, clinical recovery is achieved. Indications for shunt surgery include:

　　(1) Age: Children over 6 years of age, and the diameter of the anastomotic blood vessels should be preferably above 0.6cm.

　　(2) General condition: Children generally have a good general condition, with a total plasma protein level above 6g and albumin above 3g.

　　(3) Medical history: Patients with two or more episodes of bleeding in their medical history, or one episode of bleeding with splenomegaly and hypersplenism.

　　(4) There are obvious esophageal varices: Children without a history of vomiting blood, but with obvious esophageal varices upon examination. In recent years, due to the development of microsurgery, the success rate of small-caliber vascular anastomosis has significantly increased, and there have been reports of successful shunt surgery in infants and young children. The effect of shunt surgery for intrahepatic portal hypertension is not as good as that for extrahepatic portal hypertension. After portal-systemic shunt surgery, some harmful substances can enter the systemic circulation without being detoxified by the liver, which increases the incidence of hepatic encephalopathy.

　　3. Conservative therapy

　　(1) Patients with liver cirrhosis: After successful surgery, they can no longer experience massive hemorrhage, but liver function generally continues to decline, and the prognosis is poor. If liver cirrhosis has developed to severe liver cell damage, showing ascites or jaundice, from the perspective of long-term effects, splenectomy has no actual therapeutic value, and conservative therapy can be adopted.

　　(2) Esophageal varices: For the treatment of esophageal varices, emergency surgery is not recommended for patients with acute esophageal variceal rupture and bleeding. Conservative therapy using hemostatic drugs should be adopted. Vasopressin (vasopressin, pitressin) 0.1-0.2U/min can be injected intravenously, which can cause vasoconstriction of the visceral arteries and hepatic arteries, thereby temporarily reducing portal vein pressure and stopping bleeding. The side effects are hypertension, circulatory expansion, and hyponatremia.

　　Second, Prognosis

　　The prognosis of this disease is usually chronic, and the final outcome is often due to emaciation, exhaustion, uncontrollable massive hemorrhage, severe liver failure, or secondary infection, leading to death. Some late-stage patients also have a chance of cure after splenectomy. A few patients have a rapid progression of the disease, and they can rapidly enter the advanced stage within 1 to 2 years.