Acute superior mesenteric artery embolism or thrombosis
Introduction
Introduction to acute mesenteric artery embolization or thrombosis The emboli that causes embolization of the superior mesenteric artery originates from the heart. Patients often have a history of heart disease, such as valvular heart disease, atrial fibrillation caused by various causes, myocardial infarction and bacterial endocarditis. basic knowledge Sickness ratio: 0.0002%-0.0005% Susceptible people: no special people Mode of infection: non-infectious Complications: gastrointestinal bleeding, intestinal obstruction, shock
Cause
Acute mesenteric artery embolism or thrombosis
(1) Causes of the disease
Most emboli are derived from the heart, left atrium from rheumatic heart disease and chronic atrial fibrillation, left ventricle after acute myocardial infarction, or wall plugs formed after previous myocardial infarction, endocarditis, valvular disease or valve replacement After, it can also come from self-shedding, or shedding due to cardiovascular catheter operation. If the cause is unknown, the superior mesenteric artery is separated from the abdominal aorta at an acute angle, which is almost parallel to the aorta and blood flow. The mainstream direction is the same, so the embolus is easy to enter and form an embolism. The acute mesenteric artery thrombosis occurs almost at the opening of the original arteriosclerotic stenosis. In some causes such as congestive heart failure, myocardial infarction, dehydration, cardiac output The sudden decrease in the amount, or the reduction of blood volume caused by major surgery, can also be caused by the dissection of the aortic aneurysm, oral contraceptives, and iatrogenic injury.
(two) pathogenesis
The embolus is usually blocked in the natural stenosis of the superior mesenteric artery, such as in the distal branch of the distal branch of the jejunum, or in the distal part of the jejunum, and thrombosis occurs in the 1 cm of the superior mesenteric artery. In the hardened part, whether it is embolus or thrombus formation, the artery is blocked, the distal branch is paralyzed, the affected intestine is pale, in a contracted state, the intestinal mucosa is intolerant to ischemia, and the acute mesenteric artery is occluded for 10 minutes, the intestinal mucosa The ultrastructure is obviously changed. After 1 hour of ischemia, the histological changes are clear. Submucosal edema, mucosal necrosis, early acute ischemia, intestinal smooth muscle contraction, and then relaxation due to ischemia, blood vessels The sputum disappears, the blood in the intestinal wall stagnates, cyanosis, edema, and a large amount of protein-rich liquid infiltrate into the intestinal lumen. Although the pathophysiological changes are obvious in a short time after ischemia, if the arterial blood flow is restored, the small intestine can still have vitality. However, there will be obvious reperfusion injury. After the ischemia continues for a long time, the muscle and serosa will be necrotic, and peritonitis will appear. The intestine is purpura or dark black, and the serosa is present. Wet sample, easy to break odor, bacteria in the intestinal cavity, toxic products are absorbed, and soon shock and metabolic acidosis occur due to poisoning and loss of large amount of fluid, vascular occlusion at the exit of superior mesenteric artery, can cause below the Treitz ligament The ischemic necrosis of all small intestines and right colon is the most common site below the exit of the middle cerebral artery. It can also cause most of the small intestine necrosis between the Treitz ligament and the ileocecal valve. The closer the occlusion is to the distal end of the trunk, the extent of the affected small intestine The smaller, when the mild ischemia is corrected, the intestinal mucosa will regenerate, the new villi shape is abnormal, there is atrophy, and there is temporary malabsorption, and then gradually recover, part of the necrotic intestinal tissue will be after the scar is healed. Segmental stenosis of the small intestine occurred.
Prevention
Acute mesenteric artery embolization or thrombosis prevention
Treatment of primary disease (such as valvular heart disease, atrial fibrillation caused by a variety of reasons, myocardial infarction and bacterial endocarditis, etc.), prevention of embolism or thrombosis leading to the disease.
Complication
Acute mesenteric artery embolism or thrombosis complications Complications, digestive tract bleeding, intestinal obstruction, shock
1. In the early stage of the onset of gastrointestinal bleeding, the patient's vomit is often a dark red gastrointestinal fluid without clots and discharged bloody stool.
2. After 6 to 12 hours of onset, the patient may have paralytic ileus.
3. Late peritoneal irritation and toxic shock.
Symptom
Acute mesenteric artery embolism or thrombosis symptoms Common symptoms Abdominal pain, abdominal distension, diarrhea, abdominal muscle tension, acute abdomen, peritonitis, peritoneal irritation, atherosclerosis, nausea, intestinal paralysis, soft palate
The superior mesenteric artery embolism or thrombosis causes ischemia, so most of the clinical manifestations of the two are the same. The patient has a history of coronary heart disease or atrial fibrillation, most of which have arteriosclerosis, and one third of the patients with embolism have limbs. Or the history of cerebral embolism, because the symptoms of thrombosis are not like embolism, only a small number of patients were admitted within 24 hours after the onset, and 90% of embolized patients were treated within 1 day.
Severe abdominal cramps are the first symptoms, difficult to relieve with general drugs, can be full or abdominal, umbilical, upper abdomen, right lower abdomen or suprapubic area, early due to intestinal fistula, followed by intestinal necrosis The pain is persistent. Most patients are accompanied by frequent vomiting. The vomit is bloody. The nature of abdominal pain, the process of evolution of the site and course of disease have many similarities with the forms of other acute abdomen. Because of its lack of obvious clinical features. The incidence rate only accounts for 0.23% to 0.7% of the total number of patients with intestinal obstruction. Therefore, clinicians often have insufficient understanding of the disease, and the rate of misdiagnosis is high. Until the late peritoneal irritation and toxic shock occur, although the internal environment has been actively treated, Serious imbalance and loss of opportunity, early, abdomen no fixed tenderness, bowel sounds active or hyperthyroidism, easy to be misdiagnosed as other diseases, after 6 ~ 12h onset, patients may have paralytic ileus, there is obvious abdominal swelling , tenderness and abdominal muscle tension, bowel sounds weakened or disappeared and other manifestations of peritonitis and systemic reactions, gastrointestinal bleeding in the early stage of the disease, patients often vomit The dark red gastrointestinal fluid without blood clots and the bloody bloody stool are caused by acute mesenteric artery occlusion, intestinal wall ischemia, hypoxia, intestinal mucosal necrosis, and plasma exudation to the intestinal lumen.
Examine
Examination of acute mesenteric artery embolization or thrombosis
It can be seen that the white blood cell count is more than 20,000, and there is blood concentration and metabolic acidosis.
Abdominal X-ray film is difficult to clear the phenomenon of intestinal ischemia. It shows only large in the early stage, and the small intestine has moderate or mild flatulence. As the disease progresses, it can be seen in the intestinal cavity, the liquid surface, and the intestinal tract that remains unchanged after several hours. There is an image of intestinal obstruction. In the case of advanced paralytic ileus, the flatulent intestine to the middle of the colon is suddenly interrupted.
Color Doppler ultrasound can directly display the mesenteric vessels and their adjacent structures. It can be seen that the strong echogenic mass with the inner diameter of the lumen of the vessel blocks the lumen of the vessel, and the color flow and spectral Doppler signal are not detected in the lumen. Screening for cases of suspected acute superior mesenteric artery occlusion, but the diagnosis rate is not high due to the influence of flatulence and intestinal fistula. If the image of the superior mesenteric artery thrombus can be detected, it provides important diagnostic information for the clinic, and can be operated in combination with clinical manifestations. Exploring the indications.
Abdominal selective angiography has a high diagnostic value for this disease. It can not only help diagnosis, but also identify arterial embolism thrombosis or vasospasm. It is the most reliable method for diagnosing acute superior mesenteric artery occlusion. Early diagnosis is also conducive to the choice of treatment. CT, MRI, and laparoscopy are helpful for early diagnosis, but not as accurate and accurate as angiography. When there is a suspected mesenteric artery occlusion, it should be in a conditional hospital. Do not hesitate to perform superior mesenteric artery angiography, arterial embolization mostly in the opening of the middle cerebral artery, the contrast agent suddenly interrupted 3 to 8 cm below the opening of the superior mesenteric artery, thrombosis is often within 3 cm of the superior mesenteric artery opening from the aorta, There is a vascular shadow interruption. The small embolus is characterized by occlusion in the branch of the mesenteric artery. Sometimes the renal artery or other visceral artery is blocked. The vasospasm shows a narrowing but no interruption of the vascular shadow. After the nature and location, the arterial catheter can be maintained in situ to give vasodilators such as papaverine, benzylamine Retinal (regitine) and the like to relieve vasospasm caused by embolization, and to maintain the operation after the drug combined with thrombectomy or embolization treatment, can improve the survival rate of ischemic intestine, and can also use this catheter after surgery Re-contrast to understand the condition of the mesenteric vascular circulation.
Diagnosis
Diagnosis of acute superior mesenteric artery embolization or thrombosis
Diagnostic criteria
If the patient has a history of heart and arterial embolism before the illness, he should be highly alert to the occurrence of this disease. Therefore, he has a history of heart and arteriosclerosis, sudden onset of severe abdominal pain, continuous aggravation, general analgesics, and gastrointestinal bleeding. It is regarded as an early sign of acute mesenteric artery occlusion. It is called the Bergan triad of acute mesenteric vascular occlusion, which is acute and without corresponding signs of upper abdomen and umbilical pain, organic and complicated atrial fibrillation, gastrointestinal The performance of emptying the road, etc., but pay attention to some elderly patients and patients with cerebral infarction, the degree of response to the disease and the ability to express weakened, should pay more attention to the positive results of the examination and changes in the condition, abdominal hemorrhage should consider the mesenteric artery occlusion May be, but must be differentiated from diseases such as pancreatitis and intestinal stenosis.
The following factors should be considered for the possibility of this disease:
1. Rheumatic heart disease, atrial fibrillation, bacterial endocarditis, myocardial infarction and atherosclerosis.
2. Sudden abdominal abdomen, abnormal colic and persistent, and gradually increased, but the early signs are not obvious.
3. Abdominal pain, diarrhea with bloody watery stools and nausea, vomiting.
4. After abdominal surgery, there is atypical abdominal pain, abdominal distension, bloody stool and peritoneal irritation are not obvious. Color Doppler ultrasound and B-ultrasound examination can help to confirm the diagnosis, and mesenteric angiography or DSA examination can accurately diagnose, is diagnosed. gold standard.
Differential diagnosis
Peptic ulcer perforation
After perforation of the stomach and duodenal ulcer, it is characterized by severe pain in the upper abdomen and rapid spread throughout the abdomen, with abdominal plate-like tonic, full abdominal tenderness and rebound tenderness, intestinal dullness shrinks or disappears, X-ray shows underarm There is a loose body in the abdominal cavity, and the patient has a history of ulcers in the past.
2. Acute intestinal obstruction
Abdominal bulging, abdominal pain is intensely paroxysmal, physical examination shows intestinal or reverse peristaltic waves, bowel sounds are hypertrophic or metallic tones, when paralyzed intestinal obstruction, the bowel sounds weaken or disappear, the abdomen X-ray or plain film examination showed multiple stepped fluid levels in the intestine, and a few patients had a history of abdominal surgery.
3. Acute pancreatitis
Because the pain site and the nature of pain in acute pancreatitis and acute cholecystitis are similar, the identification of the two is also very important. 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. The blood and urine amylase increase is more significant than the acute cholecystitis. B-ultrasound can reveal diffuse or localized pancreas. Increase, the internal echo of the pancreas is weakened, the pancreatic duct is dilated, etc., but it must be pointed out that when the gallstone blocks the common bile duct or the ampulla of the ampulla, it can cause acute pancreatitis. Therefore, acute pancreatitis and acute cholecystitis or cholangitis can be simultaneously presence.
4. Ectopic pregnancy rupture
There is no history of ulceration and history of menopause. The abdominal pain is mostly in the lower abdomen, accompanied by vaginal bleeding. B-mode ultrasound can confirm the diagnosis.
5. Ovarian cyst pedicle torsion
No history of ulcers, pain often occurs suddenly, showing severe severe pain, the pain is abnormal in the lower abdomen, a small number of patients can be shocked due to severe pain, gynecological examination and B-ultrasound, CT and other tests can establish a diagnosis.
