ischemic colic
Introduction
Introduction to ischemic intestinal colic Ischemic intestinal colic (ischemicintestinalcolic), also known as chronic mesenteric ischemia (chronic mesentericischemia), refers to repeated episodes of intense paroxysmal upper abdominal cramps or pain around the umbilicus. basic knowledge The proportion of illness: 0.005% Susceptible people: good for the elderly Mode of infection: non-infectious Complications: diarrhea, bloating, malnutrition, intestinal obstruction
Cause
Causes of ischemic intestinal colic
Arterial disease (20%):
The vast majority occur on the basis of atherosclerosis. The arterial wall thrombus and atheromatous plaque cause stenosis or even occlusion. As the blood vessels gradually occlude, the collateral circulation of nearby blood vessels follows. Established, such as aneurysms, arterial stenosis, arteritis.
Venous occlusive disease (15%):
Intravenous thrombosis often occurs in intra-abdominal infections, blood diseases, trauma, pancreatitis, major intra-abdominal surgery, connective tissue disease, long-term use of adrenal cortex hormones and long-term use of oral contraceptives.
Low perfusion heart failure (10%):
Shock and blood volume caused by various reasons, blood pressure suddenly drops, drugs or some endocrine causes small blood vessels in the intestine to contract.
Small vascular inflammatory disease (10%):
Such as Wegener granulomatosis, systemic lupus erythematosus, Behcet's disease, dermatomyositis, diabetes, hypertension, nodular polyarteritis and allergic purpura may also involve small and medium arteries leading to stenosis and occlusion.
Other (5%):
Increased intra-intestinal pressure such as tumor obstruction, intractable constipation, abdominal trauma and radiation sickness.
The onset of the disease is often the result of multiple factors, and the celiac artery and the superior and inferior mesenteric arteries are involved at the same time.
Pathogenesis
The vast majority of intestinal blood supply comes from the three main branches of the ventral side of the abdominal aorta, namely the celiac artery, the superior mesenteric artery and the inferior mesenteric artery.
There are more than 10 branches of the superior mesenteric artery supplying the small intestine, while the ileal artery, the right colonic artery and the middle colonic artery respectively supply the same name of the intestine; the main branch is supplied from the distal end of the duodenum to the distal end of the transverse colon, and the superior mesenteric artery is fan-shaped. There are 3 to 5 arterial arches connected to each other before the end of the arteries, and there are lateral branches communicating between the arches. In the three main branches, the superior mesenteric artery has the largest lumen.
The inferior mesenteric artery is the smallest of the three main branches, and its branch supplies the distal end of the transverse colon, the descending colon, the sigmoid colon and the proximal rectum, and branches through the Riolan arterial arc (formed by the transverse mesenteric) and the peripheral arteries and the superior mesenteric artery. Another branch is connected to the middle and lower iliac artery (systemic circulation).
In addition to the above two supply intestines, other abdominal organs such as the stomach, liver, spleen, pancreaticoduodenal, etc. are supplied by the celiac artery, and are connected to the superior mesenteric artery via the pancreas and duodenal artery. Many, blood supply is rich, and each question is like a network-like communication, so it is rare to have ischemic infarction.
The visceral shunt of the aorta is not much, about 30% of the cardiac output. The blood flow per unit tissue of the small intestine is about 5 times that of the stomach and 2 times that of the colon. It is generally believed that the blood flow of the mucosa accounts for the total blood flow of the intestine. 70%.
Arterial oxygen partial pressure and blood flow in the mesentery, the relationship between vascular resistance and vascular pressure determine the supply of internal organs, the mesenteric blood flow is directly proportional to the pressure of the mesenteric vessels, and inversely proportional to the resistance of the mesenteric vessels, the stomach The intestinal oxygen uptake is constant, although the range of blood flow changes is quite extensive to prevent damage caused by hypoxia, but the intestinal mucosal metabolism is most active, so it is most sensitive to hypoxia, during the postprandial period, the small intestine Increased blood flow by 30% to 130%, which is beneficial for blood redistribution in the mucosa and submucosa.
Because of the celiac artery, the superior mesenteric artery and the inferior mesenteric artery have more collateral connections, when a main branch, such as the superior mesenteric artery, occurs chronic occlusion, the other branch of the main branch can compensate for blood supply. Therefore, symptoms rarely occur. Even if the occlusion is suddenly occluded (such as an embolus), the collateral artery may supply a considerable amount of blood in a short period of time. The intestinal tissue does not cause necrosis. When the occlusion is relieved, the collateral blood supply also stops. Ischemic tolerance is greater. When the diameter of the superior mesenteric artery is reduced by 80% or the blood supply is reduced by 75%, there is no change in the intestinal wall within 12 hours. Only when 2 to 3 large branches of the abdominal aorta are involved in occlusion. Or severe stenosis, severe stenosis of the main mesenteric artery, accompanied by collateral circulation compensation, blood flow is significantly reduced, chronic blood supply to the intestinal wall is incomplete, intestinal ischemia symptoms.
The blood supply of the intestine depends on the above-mentioned arteries, and the receptor cyclic arterial pressure is reduced (shock) and the arteriolar resistance is increased (adrenalin, digitalis preparation, and some diseases such as vasculitis complicated by connective tissue diseases such as lupus erythematosus) The effects of factors are ischemia, but there are also local adjustments, which are achieved by internal and external mechanisms. Local metabolic factors and muscle tissue can change the tension of the vessel wall and regulate local blood flow.
Pathological changes in severe intestinal ischemia include: intestinal wall edema, congestion, intramucosal hemorrhage and necrosis of different sizes, hyperplastic repair, ulcer formation, perforation and inflammatory degeneration.
1. Edema: Most of them have edema of different severity, especially in the mucosa and submucosal edema, and edema is not obvious in arterial or small vascular disease.
2. Bleeding: 100% of patients have different degrees of bleeding, especially venous obstruction often without obvious necrosis, mainly edema and hemorrhage. The clinical manifestations of severe hemorrhage are bloody stools and even hemorrhagic shock.
3. Necrosis: severe damage caused by ischemia, necrosis and light weight, often coagulative necrosis or hemorrhagic necrosis, can be expressed as solitary, focal, multiple, segmental, large lamellae mucosal necrosis From the mucosal layer, the outer layer can be extended to the muscular layer and the serosal layer. The superficial necrosis can form a pseudomembrane, and severe necrosis can be manifested as gangrene.
4. Erosion and ulceration: Mucosal ischemic degeneration and necrosis can cause erosion and ulcer formation. The size of the ulcer varies, which can form a multi-focal small ulcer, which looks like ulcerative colitis. In chronic cases, deep ulcers can form, and the ulcer can be formed. Sexual ulcers can even cause perforation, and chronic ones often have intestinal adhesions.
5. Repair: epithelial and interstitial may have varying degrees of hyperplasia or regenerative repair changes, in the chronic period of granulomatosis and fibrosis, and finally fibrous scar formation, and even tumor-like mass, intestinal wall due to interstitial hyperplasia And fibrosis and thickening, intestinal stenosis and deformation can also be seen in the repair process, epithelial and interstitial can form polypoid or nodular lesions.
On the basis of the above pathological and secondary bacteria, almost all of them are accompanied by different degrees of inflammation. The intestinal gas forms a balloon swelling through the lesion to the subserosal layer of the intestinal wall, and forms an abdominal abscess and peritonitis after perforation. Vasculitic ischemic bowel disease itself is an inflammatory lesion, a non-suppurative inflammation centered on blood vessels, which can affect the entire layer of the intestinal wall, and even the peri-intestine.
The extent of intestinal lesions can be limited to a small intestine or the entire intestine, depending on the location and extent of vascular occlusion, the formation of occlusion and the establishment of collateral circulation, the lesion distribution can be isolated, single Or multiple segmental distribution, simple stenosis of the small intestine during barium examination; segmental stenosis if it is intermittent fiber scars, called "sausage string" sign.
Prevention
Ischemic colic prevention
1. Treat the primary disease and eliminate the cause.
2. Some people think that 50% of patients with chronic mesenteric ischemia are prophylactic for acute mesenteric ischemia and preventive angioplasty, but this measure is still controversial in academia.
Complication
Ischemic colic complications Complications, diarrhea, bloating, malnutrition, intestinal obstruction
Due to malabsorption caused by intestinal ischemia, chronic diarrhea, steatorrhea, bloating, etc.; the course of the disease is progressive, that is, as the disease progresses, the patient will develop symptomatic fear, resulting in weight loss and malnutrition, accompanied by bloating, constipation Patients may have acute mesenteric thrombosis and intestinal obstruction.
Symptom
Ischemic colic symptoms common symptoms nausea and abdominal distension abdominal pain abdominal discomfort systolic diarrhea dull pain intestinal paralysis soft phlegm
Often older, with a history of heart disease or peripheral vascular disease, more men than women, abdominal pain or abdominal discomfort are the most common symptoms, pain is often located in the upper abdomen or umbilical circumference, can also be diffuse, can be radiated to the back and The typical symptoms of the neck are 15 to 60 minutes after a full meal, lasting 2 to 3 hours. The initial stage of the disease may be paroxysmal dull pain. As the disease progresses, the symptoms may gradually increase with persistent dull pain and spastic colic. Occasionally severe colic, may be accompanied by nausea, vomiting, etc., so the blood supply can not meet the needs of the small intestine digestive function, the symptoms and food intake parallel, change the position such as the position or prone position pain can be reduced, physical strength Activities can promote abdominal pain, intermittent claudication, etc., because the blood flow to the lower limbs mainly comes from the visceral circulation, the inferior mesenteric artery passes through the anastomosis of the rectum, and the rectal branch of the internal iliac artery communicates with the systemic circulation, walking and activity age. Xie speeds up, resulting in a decrease in visceral blood flow, followed by abdominal pain.
There are no special signs in physical examination. About 80% of patients have audible and systolic murmurs in the upper abdomen, but they are not specific and are not sensitive. The elderly with chronic disease, chronic malnutrition, weight loss, soft abdomen, no tenderness, even pain The abdomen is still soft during the attack.
Typical clinical manifestations: postprandial episodes of upper abdominal pain, weight loss due to frequent eating, and even bloating, diarrhea, etc., evidence of ischemic examination and selective mesenteric angiography showing abdominal aorta, superior mesenteric artery And the three sub-arteries of the inferior mesenteric artery, at least two of the severe stenosis and occlusion sites and the tortuous collateral circulation of the blood supply artery, can be diagnosed, the elderly, with a history of atherosclerosis suggest potential.
Examine
Examination of ischemic colic
Routine blood tests can be associated with normal or malnourished records, stool tests, and fat-pollers for those suspected of having diarrhea.
Abdominal plain film
Should be routine, generally no features, can exclude gallstones, urinary stones and obstruction.
2. X-ray tincture examination
It can express simple stenosis of small intestine; if it is intermittent fibrous scar, it is characterized by segmental stenosis, called "sausage string" sign, and superior mesenteric artery disease often causes a large range of intestinal segment lesions, involving small intestine to colon.
3. Ultrasound examination
Doppler ultrasound can measure the blood flow velocity of blood vessels, determine the degree of vascular stenosis, and the location, showing the size and location of plaques, stenosis and occlusion in the main arteries of the abdominal cavity. Ultrasound examination excludes the hepatobiliary and pancreatic system and urinary system diseases.
4. Endoscopy
Except for peptic ulcers and digestive tract tumors, gastroscopic examination revealed erosion of the antrum and duodenum.
5. Angiography
The most reliable method for diagnosing this disease, aortic angiography, selective celiac artery, superior mesenteric artery and inferior mesenteric artery angiography for the diagnosis of vascular stenosis, determination of the nature, location, extent and extent of vascular occlusion and collateral circulation The establishment of the lateral position and anterior and posterior slices, can show obvious atherosclerosis and some hemodynamic changes, common arteriosclerotic lesions within 1 ~ 2cm of the aortic root, often 2 to 3 mesenteric Arterial stenosis or complete occlusion, the degree of stenosis is more than 50%, there is blood regurgitation to the abdominal aorta, accompanied by a large and tortuous collateral blood supply artery, sometimes only 1 to 2 main branches are narrow but no large sputum Distorted collateral vessels still cannot be diagnosed. Clinical vascular lesions are not consistent with symptoms. 75% of people may have angiographic findings of mesenteric arteriosclerosis. It is worth noting that asymptomatic elderly in mesenteric angiography 10 % to 20% have obvious lesions.
6. Tension measurement
Tension is a method for detecting the pH (pHI) in the intestinal wall. The tensiometer is a translucent capsule attached to the end of a thin silicone tube. The nasal cavity is inserted into the intestine, and the liquid in the capsule is measured to measure CO2. The CO2 inside is balanced with the CO2 in the intestinal wall, so the CO2 in the capsule is also balanced with the CO2 in the intestinal wall. The partial pressure of CO2 in the cyst fluid and HCO3- in the arterial blood are substituted into the Henderson Hasselbalch equation. The pHI value in the wall of the intestine is a useful method for monitoring cellular metabolism and tissue hypoxia. When the intestinal oxygen supply falls below the critical value, the pH of the tissue suddenly drops. Poole et al found that the intestinal blood flow decreased and pHI showed The linear relationship can sensitively reflect the decrease of intestinal blood flow, and the results can be repeated. The pre-prandial and post-prandial tension measurement method can be used to determine the pHI value in the small intestine wall to provide an effective means for diagnosing intestinal ischemia.
Diagnosis
Diagnosis and diagnosis of ischemic colic
diagnosis
Early clinical manifestations are atypical, and laboratory tests, radiology, and ultrasound Doppler are normal. In addition, angiography is easily overlooked for a variety of reasons, so early or preoperative diagnosis is very difficult.
Differential diagnosis
1. Stomach ulcer: The upper abdominal pain often occurs 0.5~1h after meal, and gradually relieves itself after 1~2h, but the episode has periodicity, which is easy to occur in the early spring and late autumn season. The pain can be relieved by taking antacid and mucosal protective agent. Gastroscopic examination can be confirmed.
2. Chronic pancreatitis: abdominal pain after eating, weight loss, diarrhea, indigestion and other symptoms, similar to this disease, according to abdominal B-mode ultrasound, CT, MRCP, ERCP and abdominal plain film examination can be identified.
Sublingual arcuate ligament compression syndrome: more common in young women, male to female ratio of 1:3, manifested as intermittent abdominal pain associated with diet, with nausea, vomiting or diarrhea, weight loss, weight loss and malnutrition, physique Examination can be heard in the abdomen and squeaking during the systolic period. Most of the pathogenesis is caused by ischemia of the inferior orbital ligament or celiac ganglion compression of the celiac artery. Angiography can confirm compression or stenosis. End expansion without atherosclerosis.
Should also be differentiated from gastrointestinal tumors, Crohn's disease, Crohn's disease, pseudomembranous colitis, hemorrhagic enteritis, pancreatic cancer, biliary tract disease, renal colic, etc. Some types of Crohn's disease may be ischemic bowel Chronic type of disease, especially those with proliferative occlusive vascular disease.
