mesenteric vein thrombosis
Introduction
Introduction to mesenteric venous thrombosis Mesenteric venous thrombosis (MVT) is less common than superior mesenteric artery embolism. Because the clinical symptoms and signs of MVT are not specific, and clinicians often lack understanding of the disease, the diagnosis is very difficult. Therefore, MVT is difficult to Preoperative diagnosis. basic knowledge The proportion of illness: 0.008% Susceptible people: no specific people Mode of infection: non-infectious Complications: intestinal fistula
Cause
Cause of mesenteric venous thrombosis
(1) Causes of the disease
The cause of MVT is more complicated. Some scholars divide the cause into two categories: secondary and primary:
1. Secondary factors MVT is often secondary to the following diseases:
(1) cirrhosis complicated with portal hypertension: due to portal hypertension, mesenteric venous blood flow is slow, it is sometimes prone to thrombosis.
(2) Infection of abdominal organs: such as acute appendicitis, acute pancreatitis, intestinal inflammatory disease, perforation of organs, sepsis after abdominal surgery, abdominal abscess or pelvic abscess, etc. These inflammatory lesions may directly affect mesenteric venous blood flow or It is caused by the action of bacterial toxins and their released coagulation factors to cause MVT.
(3) changes in mesenteric venous blood flow or vascular injury: including abdominal surgery, abdominal trauma and radiation injury, some scholars have found that after splenectomy, portal vein shunt can induce MVT, it has been confirmed that some patients have splenectomy after surgery Thrombocytosis increases the coagulation factor of the blood and increases the viscosity of the blood.
(4) Closed abdominal injury can damage the mesenteric vein and cause MVT.
(5) hypercoagulable state of the blood: there are considered abdominal malignant tumors such as a small number of pancreatic cancer, colon cancer patients may be accompanied by hypercoagulable state, and prone to MVT, in addition, long-term use of contraceptives can also cause MVT, the cause and blood Flow changes are related.
(6) Other rare causes include congestive heart failure, polycythemia vera, myocardial infarction and diabetes.
2. Primary factors Previously, MVT patients without these secondary factors were referred to as primary or idiopathic mesenteric thrombosis, but recent studies have found that approximately half of patients with primary or idiopathic MVT There is a history of peripheral venous thrombophlebitis or a family history of thromboembolism, so MVT may be considered a special type of thrombophlebitis. In addition, hereditary hypercoagulable state such as lack of protein C, S protein or anticoagulation Blood zymogen III can explain many primary or idiopathic cases. Therefore, blood coagulation and anticoagulant factors should be measured in patients with unexplained MVT to determine whether MVT occurs as a hereditary or congenital coagulopathy dysfunction. Caused.
(two) pathogenesis
Most of the MVT occurs in the branches of the superior mesenteric vein, and generally does not occur in the trunk, but only occurs in the inferior mesenteric vein, only 5% to 6%. After the MVT, most of the segments are small intestine infarction, and a few are all Intestinal involvement, the large intestine has a collateral circulation between the renal vein, the splenic vein, the azygous vein and the systemic circulation. Therefore, after the MVT occurs, the intestine is rarely infarcted, the affected intestine is blocked by blood circulation, and the intestinal mucosa is hyperemia and edema. , hemorrhagic and mucosal focal necrosis, thickened small intestine wall, dark red blood in the intestine, the mesentery of the affected intestine is also thickened, rubbery, mesenteric arterioles often show sputum and blood flow slowly but No occlusion.
Prevention
Mesenteric venous thrombosis prevention
For the secondary factors of the etiology of MVT (such as: cirrhosis with portal hypertension, abdominal organ infection, blood hypercoagulability, etc.) for effective prevention and treatment, to avoid further development of the disease and MVT.
Complication
Mesenteric venous thrombosis complications Complications
Intestinal fistula is a major complication after surgery. Nutritional support is of great significance to ensure the nutritional supplement of patients, prevent negative nitrogen balance, enhance immune function, and reduce the occurrence of other complications.
Symptom
Symptoms of mesenteric venous thrombosis Common symptoms Abdominal discomfort Upper vena cava obstruction High fever Diarrhea Nausea and vomiting Bowel nausea Peritonitis Appetite loss abdominal pain
Because the lesion range of MVT and the speed of thrombosis are different, the clinical manifestations of MVT vary from person to person. For example, those with less intestinal segments and slower thrombosis are only manifested by loss of appetite and abdominal discomfort. From day to week, if the lesions are wide, the rapid thrombosis is often acute, and the degree of abdominal pain is severe. Therefore, the clinical manifestations of MVT patients often lack characteristics.
1. Abdominal pain Most cases have prodromal symptoms of abdominal discomfort, followed by abdominal pain, and gradually worsened, mostly paroxysmal cramps, only a few cases with severe abdominal pain, the range of abdominal pain varies according to the severity of the lesion, light performance For localized pain, severe cases may be total abdominal pain. Most patients have a history of abdominal pain for a long time before admission. The few patients have several days, many for several weeks, and a few patients with severe abdominal pain have abdominal signs and abdominal pain. Often disproportionately the characteristics of MVT.
2. About 50% of patients with MVT in nausea and vomiting may develop nausea and vomiting.
3. A small number of patients with diarrhea or bloody stools may have diarrhea or with thin bloody stools.
4. A small number of patients with fever may have fever, but generally do not exceed 38 ° C, if there is high fever, more suggestive of concurrent infection.
5. Signs of the abdomen often have tenderness and rebound tenderness, but the degree is lighter and the muscle tension is not obvious. When a few patients palpate, they can touch the dilated and thickened intestinal fistula. The bowel sounds are normal early and often weaken or disappear. When the abdominal puncture is used to extract the reddish bloody liquid, it will help the diagnosis of this disease.
Examine
Examination of mesenteric venous thrombosis
Most of the laboratory tests can show abnormal increase of white blood cells that are not consistent with the signs. Most of them are as high as 20×109/L and have blood concentration. The fecal occult blood can be positive. Recently, experiments have shown that fatty acid binding proteins and dimers ( Dimer>20g/ml) has a certain specificity in the diagnosis of mesenteric vascular disease, reaching more than 95%, but it is still rarely used in clinical practice.
1. X-ray examination has small intestine flatulence, thickening of the intestinal wall and effusion in the intestinal lumen, and incomplete obstruction, which has a certain significance in the diagnosis of this disease.
2. Abdominal CT is helpful in the diagnosis of this disease, and can support the diagnosis of this disease from the following aspects:
(1) After thrombosis, the diameter of the superior mesenteric vein is often widened, and the diameter of the thrombus formation area is not proportional.
(2) The thrombus in the intestinal blood vessels has a higher density when it is flat, and the density is lower than the density of the surrounding vein after enhancement.
(3) The mesentery is obviously thickened due to edema and the density is increased.
(4) Intestinal wall edema thickening, CT manifested as "finger indentation sign".
Selective superior mesenteric artery angiography can detect mesenteric vascular interruption, color Doppler ultrasound, CT and other examinations can be diagnosed at about 70%, selective angiography can reach about 90%, but ultimately to be determined by surgical exploration.
Diagnosis
Diagnosis and differentiation of mesenteric venous thrombosis
Diagnostic criteria
1. Abdominal pain is subacute, gradually worsening, accompanied by signs of gastrointestinal bleeding such as bloody stools.
2. The degree of abdominal pain and abdominal signs may not be consistent, and the symptoms of abdominal pain are mild and the signs are light, which is an important feature of the disease.
3. Peritonitis is accompanied by intra-abdominal bloody exudate.
Elderly patients with the above clinical manifestations, especially those with cirrhosis, portal hypertension, and intra-abdominal infection should be highly alert to the above laboratory and imaging examinations.
Differential diagnosis
1. Acute pancreatitis In general, the pain of acute pancreatitis is more severe, and it is more common in patients with knife-like pain. In addition to the upper abdomen, the pain site can also be located in the middle abdomen and the left upper abdomen. The pain can be radiated to the lower back. Blood and urine amylase increase are more significant than acute cholecystitis. B-ultrasound can reveal diffuse or localized enlargement of the pancreas, weak echo in the pancreas, and signs of pancreatic duct dilatation.
2. Peptic ulcer perforation Peptic ulcer with perforation often has no obvious fever, and the frequency of vomiting is not frequent. As the disease progresses, the upper abdomen pain gradually becomes intense and spreads rapidly to the whole abdomen, and abdominal tenderness occurs earlier. Abdominal irritation such as migraine and abdominal muscle tonic, the liver dullness circle shrinks or disappears, abdominal fluoroscopy or plain film can find free gas under the armpit. If clinically more suggestive of acute cholecystitis, then B should be selected first. Ultrasonic examination.
3. Liver abscess can appear chills, fever, right upper abdomen pain or severe pain, the identification mainly depends on B-ultrasound, CT and other examinations, such as one or more abscesses found in the liver, and the gallbladder shows normal, it can be diagnosed as Liver abscess.
4. Acute intestinal obstruction In acute intestinal obstruction, the painful part is mostly located in the umbilical cord, which may be exacerbated. The bowel sounds are hypertrophic or metallic tones. When paralyzed intestinal obstruction, the bowel sounds are weakened or Disappeared, X-ray abdominal fluoroscopy or plain film examination showed a step-like, liquid-gas plane with different widths in the intestinal lumen, and the diagnosis was confirmed when the intestinal tube above the obstruction showed significant expansion.
5. Patients with right lower pneumonia or pleurisy with right lower pneumonia or pleurisy may present with pain in the upper right abdomen, or even severe pain, but also radiate to the right shoulder, but patients with pneumonia or pleurisy often have chills before abdominal pain. Symptoms such as fever, cough, cough and chest pain, and pain is often associated with respiratory movements. Auscultation of the lungs can be heard and paralyzed, breath sounds are weakened or disappeared, and chest X-ray or radiographs can reveal characteristic changes in pneumonia or pleurisy. Very few patients with acute cholecystitis, such as inflammation and the right lower pleura, there may be a little exudate at the lower right rib angle.
