During this 20-25 minute pre-recorded lecture, Dr. Lawrence B. Cohen discusses the topic of ischemic diseases of the intestine. This in-depth review will provide an update on this topic for your clinical practice as well as supplement your learning for the ABIM Gastroenterology and Hepatology boards.
When I turned to a discussion of intestinal ischemia. Ski mia may evolve the large intestine, the small bowel referred to as messenger of ischemia and occasionally both at the same time defected segment will depend upon the area of vasculature involved as well as a degree on the duration of blood flow interruption. The clinical course of disease of ischemia may present as acute sub acute or chronic here. It depends upon the path physiologic process. About 60% of cases of intestinal ischemia are due to acute message America ischemia or the remaining 40% constitutes either colonic ischemia arm chronic business Marcus came out. Let's look at a typical patient presenting with ischemia. This is a 78 year old female with coronary artery disease who's admitted with cram p left lower quadrant pain. Several bloody stools on physical exam. She's normal intensive heart rate of 96 it's tenderness over the left call and The white count of 14,000. And the cat scan shows thickening of the wall and stranding in the descending and sigmoid. The best step in the management of this patient would be a C. T. Angiogram, be hospitalization and I. V. Antibiotics. See surgical consultation or D. Colonoscopy. And the answer here is the oh and ask colonoscopy is indicated early in the evaluation of suspected ischemic colitis. Here we see a patient with diffuse inflammatory change. There's mucosal ulceration. Sub mucosal hemorrhage. This represents the endoscopic equivalent of thumb printing seen on radiographic imaging. These endoscopic findings are strolling suggestive. Although not diagnostic for a schema colitis. Other endoscopic findings that are sometimes seen in colonic ischemia include uh pseudo membranes, sparing of the rectum, a single stripe sign and a fairly abrupt transition from diseased to normal intestine. There's a slight predominance of females presenting with a schema colitis Roughly ratio of 60 to 40 female to male with an average age at time presentation of 70 years. The classic triad of symptoms of colon cancer leukemia consists of cramping, abdominal pain, rectal urgency and bloody stools. It's important to appreciate that the vast majority of cases of colonic ischemia are due to localized, non exclusive or non obstructive vascular disease. Consequently imaging generally does not require the use of C. T. Angio or camera says vascular occlusion and the need for subsequent intervention are not part of the treatment algorithm for the vast majority of patients with colonic ischemia. Similarly, these patients generally do not have a hyper co agreeable state and therefore Hemet geologic evaluation for a clotting disorder is generally not necessary in these patients, chronic ischemia has been associated with several medications, including a luster tron medicine use for I. B. S. Cocaine abuse and in basic Oto in the case of the use of basic Oto. This generally results in patients who are taking three tablets Or more at one time colonoscopy is the most accurate method of diagnosis As important to appreciate that 10-20% of patients with chronic ischemia will have a clinical recurrence within the next five years. the arterial supply to the intestine consists primarily of the superior mission torque artery and the inferior medicine to eric artery. The S. M. A. Provides the entire small bowel. With the exception of the proximal duodenum, all the S. M. A. And the I. Am a combined contribute to the blood supply of the colon. The intestinal tract is protected from ischemia by an extensive network of collaterals that provide redundancy in the event that vessel becomes included. These include the marginal artery of drummond, the meandering messenger eric artery and the superior and middle rectal arteries, watershed points are areas that are located at a juncture between one vessel and another. to such areas exist within the Col. one referred to as Griffith's Point, which is the splenic. If lecture, representing the overlap between the superior and the inferior messenger artery, the other being sued. X. Point, or the recto sigmoid junction, this being the watershed or overlap between the Obama and the rectal arteries. Let's talk about sites of involvement in the colon. This table shows the regions of colonic involvement in patients presenting with a scheme of colitis. Notice That 70% of patients with colonic ischemia will have involvement of the bow, at or distal to the m. Panic fleischer And the remaining 30%. We'll have involvement of the right colon. It's important to appreciate that this subset of patients with right colonic involvement have a mortality rate that is 2-3 times that patients presenting overall with colonic ischemia with an with an overall mortality of roughly 7 to 8%. While compared to patients with isolated right colonic involvement where the mortality is 20% or greater. In some instances these patients will have co existent involvement of the small bell as well. When assessing patients with colonic ischemia is important to assess the presence of risk factors. Risk factors that helped to direct management strategy as well as uh indicating which are patients that are more likely to go on to gangrenous necrosis of the veil and the need for for urgent surgical intervention. There are seven risk factors that are shown here. one of the seven represents the demographic factor to our physical findings on physical examination and four are clinical laboratory parameters. Patients with no risk factors. As was the case in the current case presentation. No risk factors can be managed on an outpatient basis. Antibiotics are not required and supportive care would be appropriate. Patients having 123 risk factors considered to have moderate disease and treatment consisting of hospitalization, I. V. Antibiotics and bail rest. Obviously we're most concerned about those that are at greatest risk progressing to inbound. The closest in the surgery. Those having four or more risk factors are the patients that we watch most closely. These patients should have C. T. Angiogram or message hurricane angiogram to define the anatomy and the involvement need to be carefully watched in an intensive care unit And there is a 20 and 30% risk that they will go on to the need for surgical intervention. Several years ago, the American College of Gastroenterology prepared best practice statements and we'll go through these briefly. We point out to you that while the recommendations for the five practice statements that will review are all considered to be strong recommendations, the level of evidence supporting each of these recommendations is fairly uh fairly low C. T. Scan with ivy and peel contrast should be the first imaging modality. They recommend that strongly even though there is only a moderate degree of evidence supporting this. Multiphasic C. T. Angio should be performed on any patient with suspected isolated right colon ischemia or patients in whom the possibility of acute message eric insufficiency or small bowel involvement cannot be excluded. Three early colonoscopy should be performed. That is within 48 hours. In patients that are suspected of having colonic ischemia for surgical intervention should be considered in the presence of colonic ischemia when accompanied by hypertension, tachycardia, abdominal pain, isolated right cohen isolated right cohen involvement or those individuals will pan colonic ischemia and northern presence of canned green. Finally antibiotic therapy should be considered for patients with moderate to severe disease as we indicated earlier. Again, I point out to you that while the recommendation is strong, the evidence supporting the practice is actually almost negligible. Well, they'll turn our attention to ischemia of the small bowel messenger of ischemia. They present with an acute or a chronic form. The acute form evolves either the arterial or venous side, evolving a single vessel. And in comparison chronic forms of mesoamerica. Ischemia involved the arterial side and result from an a throw from Bostic Process involving two or more of the splanchnic vessels, acute medicine. Terek ischemia in the vast majority of cases results from arterial disease. This may be am bolic often and emboli from the heart. These are often patients with a history of myocardial infarction, atrial fibrillation or vegetation is on the valve or an approximately or to throwem Bostic disease. These are patients present with an acute thrombosis in a vessel was significant underlying atherosclerosis and or message eric dissection, such as dissection of the superior messenger artery. A small fraction of patients with acute esoteric ischemia will have a non obstructive process. This usually results in patients with congestive heart failure and hypertension. They occur after cardiac or aortic aneurysm surgery. Cross clamping of the aorta sometimes result in vascular disease, hyperbole mia dissecting aortic aneurysm, bell distension valve Youlus, Our other causes of non obstructive, acute message or ischemia and finally abdominal compartment syndrome, messenger case. Ischemia may also result from venus involvement of usually the superior messenger in vain. This is generally a result of a thrombosis stick process and here we divide this into either primary throughout message eric vein thrombosis. In patients with a hyper collectible state or a secondary form of thrombosis in patients with inflammatory disease. Recent abdominal surgery or underlying malignancy. Most cases of acute mesoamerican sufficiency that occur in patients without underlying cardiovascular disease are due to messenger vein thrombosis. Here is a patient I presented to us in the past year. This was a 56 year old gentleman. The history of smoking alcohol, hypertension and low back pain. With herniation of the disc presented to an outside hospital with by with bilateral lower extremity pain. The limb was described as being white and pulseless facial was transferred here For evaluation of limb ischemia. Upon arrival the extremity looked normal vascular surgery felt. There was no indication of acute limb ischemia patient was in atrial fibrillation. The white count was 12 to 14,000 with 20% bandy mia Cramped. name was 1.6 facial assad attic with a lactate of 4.4. The C. T. Scan demonstrated diverticular aosis with mild mesen Tarek stranding along the descending colon thought to be likely from mild diverticulitis patient was then seen the following day by neurosurgery who had no recommendations. We recalled on the third hospital day for the patients who presented at that time with diarrhea overwhelming to the point of fecal incontinence. His abdomen was soft, there was no tenderness guarding rigidity. Although bowel sounds were absent at that time. This the white count was 16,200 craning had risen to 2.2. The ph was 7.4. The lac tape was slightly elevated at 1.9 the crp was 1 94. CK was 2300 C. Diff was negative. There were numerous red cells in the urine. We recommended a. C. T. A. Of the abdomen and pelvis. And here you see the classic picture of a patient presenting with a dissecting aortic aneurysm. This dissection originated up in the chastity of the subclavian and tracked down to the common iliac vessels. Patient was transferred to the ICU. Were supportive care was given blood pressure control was provided patient under one vascular stenting and was discharged survive was discharged several days later. Doing quite well. So the classic diagnosis of mesoamerica ischemia is based upon the uh the well known axiom. Pain add proportion to the physical examination, routine laboratory studies are usually non specific in these patients. As we saw in uh this case history lactate is elevated in 86% but it has very low specificity seem can be true for D. Dime. Er So the diagnosis generally rest upon the performance of advanced imaging tests. C. T. Angiogram has the highest sensitivity of 95-100%. It has the benefits of being rapid usually is readily obtainable. It can characteristic both the extent and the location of involved vessels and it may sometimes be helpful in assessing the extent of ischemic injury to the bow duplex Ultrasound in the hands of experienced operators is quite sensitive specific and lower costs but it does require a dedicated team of operators. Mara may or may not be an option in your institution. We recently had a patient suspected of ischemia who had a pacemaker in place and therefore could not undergo camera and successfully underwent a spank the gang angiogram. So the management of acute message eric insufficiency uh in all patients whether they arterial or venus uh occlusion. The management includes aggressive I. V. Fluid hydration. Anti coagulation is given to the vast majority of patients except those with active gi bleeding. And in general antibiotics are recommended patients presenting with arterial disease. If they have an endless that can be identified, they may be accounted for surgical and bill ectomy or alternatively from politic therapy after a thrombosis uh causing uh message eric insufficiency. These patients may be candidates for either thrown politic therapy or surgical revascularization. For those presenting due to non exclusive disease. These are often patients with significant co morbid illness. The treatment is generally corrective of the underlying condition. Emergency surgery should be an active consideration and patients with suspected now infarction based upon findings on physical examination and the appropriate supporting clinical laboratory studies, patients with Mesut terek vein thrombosis and the calculation is often the only therapy that is required surgery may be necessary at times when the presence of necrotic bell or ischemic preparation is suspected. The mortality across the board for patients with acute message Jerkins. Ischemia is 60%. That is 5-6 times greater than the mortality of patients with colonic ischemia. And the most important factor in the high mortality rate is a delay in the diagnosis and intervention. So we'll finish up with one last case 72 year old male former smoker hypertension presents with cramping pain with food ingestion, he's lost £18 over the past four months. Physical exam is normal except for an abdominal Brulee, endoscopy is normal and the sea to demonstrates high grade obstruction of the celiac and superior mission. Dark artery. Your recommendation is a frequent small meals, be oral, anti coagulation. See total parental nutrition, d surgical or endovascular revascularization. Of course, that is the answer. As we said earlier, chronic esoteric insufficiency is usually the result of occlusion of two or perhaps three of the major splanchnic vessels, Postprandial pain, fear of eating and weight loss or the cardinal symptoms. So I'll finish up by showing you this review slide summarizes what we've talked about in the last 20 minutes or so. Uh with that I will close thank you
