What Is Portal Vein Thrombosis?

Portal vein thrombosis (PT) refers to a thrombus that occurs in the trunk of the portal vein, the superior mesenteric vein, the sub mesenteric vein, or the splenic vein. Portal vein thrombosis can cause portal vein obstruction, cause portal vein pressure increase, and intestinal congestion, which is an important cause of anterior hepatic portal hypertension. Portal vein thrombosis is mostly secondary to chronic liver disease and tumor disease. Simple extrahepatic portal vein obstruction is more common in adolescents and children.

Basic Information

English name: thrombosis of portal vein
Visiting department: Hepatobiliary surgery
Multiple groups: Chronic liver disease and tumor disease

Common causes: Inflammatory, tumorous, coagulopathy, after abdominal surgery, traumatic and unknown
Common symptoms: Abdominal pain is intermittent colic, nausea, and vomiting; spleen enlarges rapidly, pain or fever in the spleen area

Causes of portal vein thrombosis

The etiology of portal vein thrombosis is very complicated, mainly including inflammatory, tumorous, coagulopathy, after abdominal surgery, trauma and unknown reasons.

Portal hypertension

Mostly due to cirrhosis of various causes and congestive splenomegaly. Mainly due to the increase in portal vein pressure, the portal vein and its branches to reduce the hepatic blood flow and blood flow speed slow down caused eddy currents, resulting in platelet accumulation and thrombosis.

2. Abdominal infection

Caused by intestinal infections of bacteria entering the portal vein system, such as neonatal umbilitis, umbilical vein sepsis, adults commonly have acute appendicitis, pancreatitis, cholecystitis, intestinal inflammatory lesions, abdominal pelvic abscess and abdomen Postoperative infections.

3. Abdominal surgery and trauma

A variety of abdominal procedures can cause thrombosis in the portal vein system, especially the most common after splenectomy, which may be related to postoperative thrombocytosis and increased blood viscosity. After splenectomy, the portal vein blood flow is reduced, and the pressure drop in the portal vein accelerates the formation of thrombus. In addition, the blood flow in the expanded spleen vein is slow, which promotes splenic vein thrombosis in the hypercoagulable state.

4. Hypercoagulable state of blood

Abdominal tumors, especially those of the colon and pancreas, are often accompanied by a hypercoagulable state of the portal vein system, which can lead to thrombosis. In recent years, it has also been found that hereditary coagulation disorders are also involved in the formation of portal vein thrombosis, including protein C, protein S, and antithrombin defects.

5. Tumors compress portal vein

Compression of tumors (such as pancreatic tumors and hepatocellular carcinoma), intestinal torsion, etc., lead to blocked blood flow in the portal vein system, leading to portal vein thrombosis.

6. Other reasons

Including primary venous sclerosis, splenic vein or mesenteric vein thrombosis, some patients have a long history of taking contraceptives, rare factors include various congestive heart failure, erythrocytosis, and so on.

7. Primary portal vein thrombosis

A small part of the extrahepatic portal vein embolism has no clear cause. May have a history of deep vein thrombosis of the extremities or wandering thrombophlebitis.

Clinical manifestations of portal vein thrombosis

Clinical typing

(1) Acute type is rare and often occurs after splenectomy; thrombosis at the anastomosis of portal-caval vein anastomosis; continuation of splenic vein thrombosis; suppurative portal phlebitis; abdominal trauma.

(2) The chronic type is more common, most of which are secondary to abnormal blood coagulation and portal vein blood stasis. The most common male cirrhosis patient, hepatocellular carcinoma is often a contributing factor.

Clinical symptoms

(1) Abdominal pain with mesenteric venous thrombosis is the earliest symptom. Abdominal pain is mostly local, and a few are diffuse throughout the abdomen. Abdominal pain was intermittent, but not severe. It can last longer, with nausea and vomiting in 50% of patients and a few patients with diarrhea or blood in the stool. If a complete obstruction occurs suddenly, severe abdominal pain around the umbilicus may appear paroxysmal, often accompanied by obvious nausea, vomiting, and exhausted bowel movements. At this time, there is no obvious sign on the physical examination. If the disease develops further, intestinal necrosis may appear. Persistent abdominal pain, bloating, blood in the stool, vomiting blood, shock, and peritoneal irritation. Abdominal puncture can draw hemorrhagic ascites.

(2) Splenic vein thrombosis is manifested by the spleen often increasing rapidly, and pain or fever in the spleen area.

(3) The clinical manifestations of portal vein thrombosis vary greatly. When the thrombus slowly develops, is confined to the extrahepatic portal vein, and is organic or rich in collateral circulation, there is no or only slight lack of specific clinical manifestations, which are often Symptom cover, acute or subacute development, manifested as moderate to severe abdominal pain, or sudden severe abdominal pain, splenomegaly, refractory ascites, severe cases even intestinal necrosis, gastrointestinal bleeding and hepatic encephalopathy.

Portal vein thrombosis

1. Blood and stool tests

When intestinal necrosis combined with bacterial infection, white blood cell count increases, fecal occult blood is positive, creatine phosphokinase is significantly increased, and even electrolyte disturbances and metabolic acidosis occur; when combined with gastrointestinal bleeding, anemia may occur and primary venous thrombosis Antithrombin factor III can be reduced or lacking. Patients after splenectomy sometimes have significantly increased platelets.

2. Abdominal puncture examination

In the presence of intestinal necrosis, hemorrhagic ascites can be drawn, and red blood cells can be seen on the microscope, and the occult blood is positive.

3. X-ray of the abdomen

When combined with intestinal necrosis or paralytic intestinal obstruction, intestinal dilatation and thickening with gas-liquid plane can be seen.

4. Abdominal ultrasound

Shows the site, size, and extent of portal vein thrombosis. The main findings were that the trunk of the portal vein, the stump of the splenic vein, and the trunk of the superior mesenteric vein were widened, and there were abnormal echoes in the veins, which were substantial irregular bright spots or isoechoic spots. In patients with cavernous portal vein, the trunk and branches of the portal vein disappeared, and the portal vein was replaced by a small, irregular tubular structure.

5. Color Doppler

The internal diameter of the portal vein, splenic vein, or superior mesenteric vein was widened and parenchymal echoes were detected. The blood flow became thinner, the blood flow signal disappeared when the obstruction was completely obstructed, and the distal venous emboli dilated.

6. Abdominal CT

Including conventional plain and enhanced scans (arterial and venous phases), the typical CT signs of portal vein thrombosis are unreinforced low-density stripe or blocky lesions in the portal vein cavity, and collateral veins and abnormal bowel segments can be seen. 90%, and splenomegaly or thick spleen can be found at the same time.

7. Angiography

Direct or indirect portal vein angiography can show the location and extent of thrombosis, and the diagnosis rate is 63% ~ 91%.

8. Magnetic Resonance Angiography

You can learn about the patency of the portal vein system, thrombosis, varicose veins, and spontaneous shunts. Extremely sensitive and specific.

Diagnosis of portal vein thrombosis

1. Abdominal pain, abdominal abscess, portal hypertension, upper gastrointestinal bleeding, etc.

2. During the clinical diagnosis and treatment of cirrhosis and portal hypertension, for acute onset, unexplained abdominal pain, bloating, bloody stools, unexplained upper gastrointestinal bleeding or splenomegaly, unexplained paralytic intestinal obstruction, combined There is a hypercoagulable state, especially for patients with portal hypertension after the interruption, should be alert to the possibility of concurrent thrombosis of the portal vein system, but the diagnosis must rely on color Doppler ultrasound or CT examination, magnetic resonance angiography for those with difficulty , Portal vein angiography.

Differential diagnosis of portal vein thrombosis

Acute intestinal obstruction

It is manifested as abdominal bulging, severe abdominal pain with paroxysmal aggravation, bowel type or reverse peristaltic wave on physical examination, hyperintestinal hypertonic sounds, sounds of gas, water, or metal. With paralytic intestinal obstruction, bowel sounds weaken or disappear. Abdominal X-ray or plain film examination showed that there were multiple stepped fluid levels in the intestinal cavity, and a few patients had a previous history of abdominal surgery.

2. Chronic cholecystitis

Most of the pain is located in the right upper abdomen, which can be radiated to the right back and scapular area. The pain often worsens after eating greasy foods. Examinations such as B ultrasound or CT can establish a diagnosis. Sometimes it can be found that it coexists with gallbladder stones, and the pancreas is normal. No expansion of the pancreatic duct. However, it must be pointed out that a small number of patients with chronic cholecystitis, gallstones and chronic pancreatitis can coexist.

3. Chronic pancreatitis, pancreatic cancer

The clinical manifestations of the patient's upper abdominal fullness, faint pain, diarrhea, and weight loss are not unique. Patients with chronic pancreatitis also have the above symptoms, and the latter may also develop jaundice and masses that resemble pancreatic cancer, so the two are identified. It is very difficult, but chronic pancreatitis generally has a long history and a history of recurrent episodes. The symptoms of diarrhea and wasting are only significant after a long course of disease. The course of pancreatic cancer is short, there is no history of recurrent attacks, and weight loss occurs earlier. During pancreatitis, plain radiographs of the abdomen can reveal pancreatic calcification points. B-ultrasound, CT or histological examination of the pancreatic mass can confirm the diagnosis.

Complications of portal vein thrombosis

The most prominent and common complication of portal vein thrombosis is esophageal and gastric fundus varices bleeding.

Portal vein thrombosis treatment

Anticoagulant therapy

As the main treatment measure, early venous heparin anticoagulation should be performed on newly occurring thrombus. Full or extensive recanalization can occur. It can also prevent the spread of blood clots, prevent intestinal ischemia in the short term, and prevent liver in the long term For external portal hypertension, oral anticoagulant therapy is recommended for at least six months.

2. Thrombolytic therapy

Thrombolytic therapy is feasible in the acute phase of this disease. The application of systemic intravenous thrombolytic drugs (urokinase) can reopen the portal vein trunk. In recent years, due to the increase in the level of intervention, more local medications have been used. Intubation of the femoral vein to the superior mesenteric artery, and early continuous thrombolysis with micropump urokinase are effective for acute PT and newly developed PT.

3. Interventional and surgical treatment

For acute portal vein thrombosis in a short period of time, portal vein incision and thrombus removal are performed as early as possible. For a long time for thrombosis, thrombosis appears to be organic, and the effect of incision or thrombolysis is poor. Shunt.

4. Transjugular intrahepatic portal vein shunt treatment

Since the introduction of the intervenous radiology technique of jugular intrahepatic portal vein shunt in 1989, it has become a treatment option for controlling portal hypertension and refractory ascites.

5. Intestinal resection

Mainly for patients with mesenteric thrombosis who have intestinal necrosis, necrotic intestinal segment and mesenteric resection are the only treatment methods, and continuous anticoagulation after surgery to prevent thrombosis.