Superior mesenteric artery thrombosis mostly occurs gradually on the basis of severe atherosclerotic occlusion. It has an insidious onset and occurs mostly in the elderly. The acute ischemic symptoms are clinically mild because of the establishment of collateral circulation due to long-term chronic mesenteric artery ischemia. However, abdominal pain may appear as the disease worsens. By the time signs and symptoms of peritonitis appear, patients have mostly developed intestinal necrosis and perforation.
The etiology mostly occurs on the basis of atherosclerosis. These patients are often combined with diffuse atherosclerosis, and a few patients have thrombosis due to spontaneous, isolated superior mesenteric artery entrapment.
In addition, after mesenteric vascular transplantation, vascular trauma and changes in blood coagulation status may also contribute to thrombosis.
Manifestations: The onset of the disease is slow, and chronic intestinal insufficiency or atherosclerotic disease is often present before the onset of the disease.
1. Abdominal pain.
Diffuse abdominal cramps appear after eating, which may radiate from the upper abdomen to the back. Episodes of abdominal pain are positively correlated with the amount of food eaten, and one episode can last 2 to 3 hours. It is also manifested as bloating and discomfort or dull pain after eating.
2. Nausea, vomiting, diarrhea.
Severe colic can be accompanied by nausea and vomiting, which worsen progressively with the symptoms. Patients are afraid to eat because of the fear of abdominal pain. Inadequate intestinal blood supply may have chronic diarrhea, frothy stools, and large amounts of fat loss in the stool.
3. Weight loss.
Because of chronic diarrhea, a lot of nutrition loss, the patient can lose weight and malnutrition.
4, acute abdominal disease:
Severe abdominal pain may occur, accompanied by frequent vomiting, vomitus is bloody, intestinal peristalsis is enhanced; bloody stool is rare in mesenteric artery embolism. Further development will result in symptoms such as intestinal necrosis and peritonitis, and even lead to shock.
5.Signs.
Early malnutrition is the main sign, and sometimes systolic vascular murmurs can be heard in the upper abdomen. Later on, intestinal necrosis occurs and signs of peritonitis and shock appear.
Examination.
1, white blood cell count may be elevated, elevated erythrocyte specific volume and acidosis, etc.
2. Early abdominal radiographs may show mild or moderate enlargement and inflation of the small and large intestines, and late stages may show generalized hyperdensity due to large accumulation of fluid in the intestinal and abdominal cavities.
3.Selective abdominal arteriography can find complete occlusion of the vessel within 3 cm of the beginning of this artery, because there is collateral circulation, so the artery distal to the obstruction can have different degrees of filling.
4. CT scan can show superior mesenteric artery thrombosis on enhanced and perfusion dynamic maps. It shows dilatation of the small intestinal canal and circular thickening of the intestinal canal with “halo-like” changes, which is also called double halo sign. In severe intestinal ischemia, the intestinal wall is indistinct and blurred, and the intestinal cavity or abdominal cavity is combined with dense bloody ascites.
Diagnosis
1. Medical history
Elderly patients with previous atherosclerotic disease, or history of mesenteric vascular graft surgery, history of vascular trauma, or blood hypercoagulable state, etc. Pay attention to distinguish it from superior mesenteric artery embolism caused by atrial thrombus dislodgement in atrial fibrillation, which mostly has a history of atrial fibrillation and other cardiac arrhythmias.
2.Clinical manifestations
Abdominal cramps after eating, chronic diarrhea, malnutrition or emaciation.
3.Auxiliary examination
Abdominal arteriogram shows atherosclerosis and thrombosis at the beginning of superior mesenteric artery, which is an important basis for diagnosis; CTA examination can also effectively show the condition of the artery.
Treatment
1.Non-surgical treatment
Anticoagulation therapy is available for mild symptoms. Due to the stenosis at the beginning of the superior mesenteric artery, it is difficult to perform selective arterial cannulation for local input of thrombolytic agent. Therefore, if the abdominal artery and the outlet of the mesenteric artery have obvious stenosis changes and the patient is in a better general condition, active surgical treatment should be performed.
2.Surgical treatment
Surgical methods include: thromboendarterectomy; bypass surgery with autologous veins or artificial vessels; resection of the stenotic segment of the mesenteric artery and then reimplantation of the artery into the abdominal aorta; other methods, such as staged balloon catheter dilation and stent placement, can also be used.
3.Post-surgical treatment
Observe abdominal symptoms and signs closely, especially in patients undergoing GI reconstruction surgery. If an intestinal fistula develops, a tube can be inserted into the distal intestinal loop through the fistula and gastrointestinal nutrition can be administered. Continue to maintain water and electrolyte balance and correct acidosis, total parenteral nutritional support therapy, improve toxic symptoms, combine antibiotics, prevent and treat DIC and multi-organ failure, and prevent the formation of thrombus after surgery.
After the occurrence of intestinal necrosis, the prognosis is still poor even after effective treatment. Patients may suffer from short bowel syndrome due to excessive removal of intestinal tubes.