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Superior mesenteric vein thrombosis

OVERVIEW

What is superior mesenteric vein thrombosis?

Superior mesenteric vein thrombosis is a type of mesenteric vascular ischemic disease, often secondary to vascular damage caused by abdominal infections, abdominal surgery, trauma, etc. It may lead to symptoms such as abdominal discomfort, constipation, acute severe abdominal pain, bloody stools, vomiting blood, and fever. In severe cases, it can result in adverse outcomes like intestinal necrosis and death [1].

Is superior mesenteric vein thrombosis common?

This condition is rare, accounting for about 3%–7% of acute intestinal ischemia cases [2]. However, the overall incidence of acute intestinal ischemia is relatively low, and there is currently no precise data available [3].

SYMPTOMS

What are the symptoms and manifestations of superior mesenteric vein thrombosis?

The symptoms of superior mesenteric vein thrombosis develop slowly and are often atypical. Early signs may include abdominal discomfort, constipation, or diarrhea. After days or weeks, sudden severe abdominal pain, persistent vomiting, hematemesis, bloody stools, abdominal distension, tenderness, reduced bowel sounds, and fever may occur [1].

What are the complications of superior mesenteric vein thrombosis?

  1. Intestinal necrosis: Prolonged ischemia caused by thrombosis can lead to intestinal necrosis, presenting as sudden abdominal pain, diarrhea, bloody stools, and vomiting.
  2. Intestinal perforation: Prolonged intestinal ischemia may result in transmural necrosis, causing perforation, with symptoms including severe abdominal pain, nausea, vomiting, and chills.
  3. Short bowel syndrome: Extensive intestinal necrosis due to thrombosis may require surgical resection, potentially leading to short bowel syndrome, characterized by diarrhea, dehydration, and malnutrition [2].

CAUSES

What causes superior mesenteric vein thrombosis?

The causes of superior mesenteric vein thrombosis can be divided into two categories: primary and secondary.

  1. Primary: May be related to hereditary coagulation disorders such as deficiencies in protein C, protein S, or antithrombin III [4].
  2. Secondary:
    • Infection: Intra-abdominal suppurative infections, such as appendicitis, diverticulitis, or pelvic abscesses, spreading to the superior mesenteric vein may cause thrombosis.
    • Diseases: Conditions like liver cirrhosis with portal hypertension or tumor compression can increase abdominal pressure, leading to local venous congestion and stasis, predisposing to thrombosis.
    • Trauma or surgery: Abdominal trauma (e.g., impact, stab wounds) or splenectomy may damage blood vessels, increasing the risk of thrombosis.
    • Medications: Oral contraceptive use may induce a hypercoagulable state, triggering thrombosis [1,4].

Who is most at risk for superior mesenteric vein thrombosis?

  1. Individuals with intra-abdominal infections: Inflammatory conditions like appendicitis or pelvic abscesses can directly damage the vascular endothelium of the superior mesenteric vein, increasing susceptibility.
  2. Long-term oral contraceptive users: Contraceptives affect coagulation, and prolonged use may lead to a hypercoagulable state, raising the risk.
  3. Patients with coagulation disorders: Those with abnormal clotting, such as deficiencies in protein C, protein S, or antithrombin III, are more prone to this condition.
  4. Severely obese individuals: Elevated abdominal pressure in these patients may cause venous congestion or stasis, increasing the risk.

DIAGNOSIS

How to Diagnose Superior Mesenteric Vein Thrombosis?

  1. Laboratory Tests: Elevated white blood cell count in blood tests suggests inflammation; increased plasma D-dimer indicates a hypercoagulable state. Positive fecal occult blood indicates gastrointestinal bleeding.
  2. Abdominal X-ray: Can aid in diagnosis. Before intestinal necrosis occurs, no specific signs are present, only intestinal gas may be detected. After necrosis, dilated bowel loops with air-fluid levels may be observed.
  3. Ultrasound: Findings such as ascites, venous thrombosis, liver cirrhosis, splenomegaly, or portal cavernous transformation suggest mesenteric ischemia, assisting in diagnosis.
  4. CT: Signs like ascites, bowel dilation, gas-fluid levels, thickened and edematous bowel walls, increased mesenteric density, edema, peritoneal thickening, or peritonitis indicate intestinal ischemia or inflammation, aiding diagnosis.
  5. Angiography: Mesenteric arteriography may reveal signs of venous thrombosis, indirectly supporting diagnosis [2].

Which Diseases Are Easily Confused with Superior Mesenteric Vein Thrombosis?

Chronic Mesenteric Vascular Occlusion: Symptoms resemble those of superior mesenteric vein thrombosis, including abdominal pain, nausea, vomiting, and diarrhea. However, severity correlates with food intake—worsening with larger meals. Angiography differentiates the two: chronic occlusion shows stenosis or occlusion at the origins of the celiac and superior mesenteric arteries, while thrombosis displays thrombotic signs [1].

TREATMENT

Which department should I visit for superior mesenteric vein thrombosis?

Gastroenterology, General Surgery, Gastrointestinal Surgery, Vascular Surgery, Emergency Department.

  1. If symptoms such as abdominal discomfort, constipation, or diarrhea occur, you can visit Gastroenterology.
  2. If sudden severe abdominal pain, persistent vomiting, hematemesis and bloody stools, abdominal distension, and tenderness occur, you can visit the Emergency Department.
  3. If diagnosed with superior mesenteric vein thrombosis and surgery is required, you can visit General Surgery, Gastrointestinal Surgery, or Vascular Surgery.

How is superior mesenteric vein thrombosis treated?

  1. Surgical treatment: Most cases require surgical intervention. Depending on the location and extent of the thrombosis, different surgical methods may be used. If the condition has a short duration (within three days) and the thrombus is confined to the main trunk of the superior mesenteric vein, thrombectomy may be performed. If the thrombus is present in the small branches of the superior mesenteric vein or intestinal necrosis has occurred, intestinal resection may be necessary.
  2. Anticoagulation therapy: Anticoagulation therapy should be initiated immediately after diagnosis and continued for three months post-surgery. Common medications include heparin, low-molecular-weight heparin, and warfarin. Although side effects such as bleeding in different areas or allergic reactions may occur, the probability is very low. These drugs are contraindicated in patients allergic to them or with bleeding tendencies. If side effects occur, consult a doctor promptly for medication adjustments.
  3. Interventional therapy: For patients without intestinal necrosis, vascular interventional therapy may be attempted. Interventional therapy has the advantages of minimal invasiveness and precise effectiveness. However, thrombosis may recur after interventional thrombolysis, so close monitoring is required [1,2,4].

Can superior mesenteric vein thrombosis be cured?

If diagnosed early and the affected area is small, the condition can be cured, but there is a possibility of recurrent thrombosis. If the disease progresses rapidly, diagnosis is delayed, or a large segment of the intestine is involved, severe consequences such as shock, intestinal necrosis, or death may occur [1].

DIET & LIFESTYLE

What should patients with superior mesenteric vein thrombosis pay attention to in daily life after surgery?

  1. After surgery, start with liquid foods such as millet porridge or meat porridge, then gradually return to a normal diet.
  2. Keep the surgical wound dry and clean.
  3. Take anticoagulant medication on time and monitor for any bleeding during treatment. Seek medical attention promptly if abnormalities occur. Do not adjust the dosage or discontinue anticoagulants without a doctor's approval.
  4. Ensure adequate rest to promote recovery.
  5. Attend follow-up examinations as scheduled by the doctor after discharge.

What dietary precautions should patients with superior mesenteric vein thrombosis take after surgery?

  1. Eat small, frequent meals with easily digestible, high-nutrient foods like steamed eggs or minced meat soup.
  2. Avoid raw, cold, highly irritating, or hard foods to prevent digestive tract irritation.
  3. Consume fresh vegetables and fruits to maintain bowel regularity, reduce digestive burden, and aid recovery.
  4. Avoid overeating, smoking, and alcohol [1,2].

PREVENTION

How to prevent superior mesenteric vein thrombosis?

  1. Actively treat underlying diseases: If there are intra-abdominal inflammatory diseases such as appendicitis or diverticulitis, prompt treatment is necessary to prevent the formation of superior mesenteric vein thrombosis.
  2. Control weight: Obese individuals (BMI greater than 28) should adjust their diet to a light, low-fat, low-salt, and sugar-free standard. Engage in at least 150 minutes of moderate-intensity exercise per week and strive to reduce weight to a healthy range (BMI between 18.5 and 24) [5].
  3. Use contraceptives wisely: Women with abnormal blood coagulation, such as deficiencies in protein C, protein S, or antithrombin III, should avoid long-term use of contraceptives and opt for physical contraception methods like condoms instead.
  4. Ensure safety: Pay attention to safety in daily life and work to avoid abdominal injuries.
  5. Regular check-ups and timely medical care: If possible, undergo an annual physical examination. Seek medical attention promptly if discomfort occurs to prevent worsening of the condition and serious consequences.