Ischemic enterocolitis examined by colonoscopy and selective angiography

Abstract

AIM: To study the value of colonoscopy and selective angiography in diagnosing ischemic enterocolitis.

METHODS: Among the 16 cases under study, 10 cases had hypertension and a history of coronary artery disease (one was hospitalized for sub-ventricular-wall infarction). The blood pressure of 10 of the 16 cases ranged from 13.9-23.8 to 13.3-14.6 kPa (170-180/100-110 mmHg). Two cases had chronic auricular fibrillation, and in four cases, a cardiogram showed left-front branch conduction block. Sixteen patients were examined by colonoscopy. Among them, 14 cases had a long course of angiocardiac disease, and were further examined by selective mesenteric inferior angiography.

RESULTS: The colonoscopy revealed local mucous hyperemia edema and blood on contact. Lesions were found in the sigmoid colon in four cases, in the descending colon in eight cases and in splenic flexure in four cases, which suggests that the lesion always appeared in the left part of colon. There were different degrees of inflammatory cell infiltration, submucous bleeding, edema, fibro-embolism and hemosiderosis by biopsy in the 16 patients whose membranes affect part of the enteral wall. Of the 14 patients examined by mesenteric inferior angiography, 3 cases showed mesenteric amphraxis inferior and formation of collateral circulation. There were different degrees of stenosis in the other 11 subjects’ mesenteric inferior cavities which grew slim and their branches were stenotic, so the radiographic image was not complete and the ends of some branches even cannot be seen.

CONCLUSION: The colonoscopy and the selective mesenteric inferior angiography are both helpful in the diagnosis of ischemic enterocolitis.

Key Words: Ischemic enterocolitis, Colonoscopy, Selective angiography

INTRODUCTION

Ischemic enterocolitis is caused by the decrease or cessation of colon wall blood perfusion, which results in ischemic change of colon wall. This causes abdominal pain, diarrhea, hematochezia, mucous stool with blood and other non-characteristic symptoms, and it is hard to diagnose at the early stage[1-4]. There were 16 cases in our department from 1996 to 2002 whose diagnoses were achieved by colonoscopy. Fourteen of these cases were given selective mesenteric inferior angiography so that the etiological diagnosis could be achieved. Internal medical care was effective in all 16 patients in the study.

MATERIALS AND METHODS

Patients

Among the 16 cases under study, there were 10 males and 6 females with an average age of 70. Ten cases had hypertension and a history of coronary artery disease (one was hospitalized for subventricular-wall infarction). The blood pressure of 10 of the 16 cases ranged from 13.9 to 23.8 to 13.3-14.6 kPa (170-180/100-110 mmHg). Two cases had chronic auricular fibrillation, and in four cases, a cardiogram showed left-front branch conduction block. All of them complained of pain in the left quadrant with dark-red mucous bloody stool or hematochezia, and most of them (12/16) had a fever. They were all examined by colonoscopy two days after they were hospitalized and 14 of the patients with chronic cardiovascular diseases also received selective mesenteric inferior angiography.

RESULTS

Lesions were found in the sigmoid colon in four cases, in the descending colon in eight cases and in splenic flexure in four cases, which suggests that the lesion always appeared in the left part of colon. Lesions had local mucous hyperemia, edema and blood on contact. Biopsy showed that there was inflammatory cell infiltration, submucous bleeding, edema, fibro-embolism and hemosiderosis in all 16 cases. Eight specimens showed hyperplasia of granular tissue and fibrosis.

Selective mesenteric inferior angiography was performed in 14 cases. The results showed that there was fragmentation in blood vessels 2 cm away from the inferior mesenteric artery and a lack of local circulation. There were several irregular collateral circulations toward the left part of colon along the superior fragmentation in three cases. In other cases, parts of the cavities of the inferior mesenteric artery became slim. There was obvious narrowing in primary part and related branches, so the radiographic image was not complete and the ends of some branches even cannot be seen.

DISCUSSION

Ischemic enterocolitis is caused by ischemia leading to colon wall mucous necrosis, exfoliation, bleeding or inflammation which produces abdominal pain, hematochezia, mucous stool with blood, and fever [5-7]. Non-characteristic symptoms make it extremely difficult to distinguish between enterocolitis, chronic ulcerative colitis, intestinal parasitosis and even early colon tumors. Four patients were diagnosed as having “enterocolitis” and “gastrointestinal tract infection” before they were referred to our hospital, where the diagnosis of “ischemic enterocolitis” was proven by colonoscopy. In the other 12 cases, four patients were diagnosed as having ischemic enterocolitis when they were first seen, and the others were hospitalized for “enterocolitis” and “gastro-intestinal tract infection” or other diagnoses. All of their diagnoses were confirmed by colonoscopic examination and biopsy. Cases all showed a great deal of fibro-embolism and hemosiderosis, symptoms characteristic of the disease which may be used to distinguish it from other kinds of enterocolitis [5].

Ischemic enterocolitis is induced by poor blood supply to the colon wall which results in ischemic change. One potent treatment is to vasodilate the surrounding blood vessels to recover blood supply. This acts to resolve the colon wall ischemia such as to reduce clinical manifestations, to restore colon wall function and to prevent colon wall necrosis which occurs when local ischemia develops into general ischemia[3]. Sixteen patients were treated with papaverine, prostaglandin E and pancreatic glucagons. After 2 days of medication, some patients felt better. Patients’ signs and symptoms essentially disappeared after 10-14 d medication. Patients were reexamined by colonoscopy after treatment to identify whether their colon wall lesion recovery was in line with their improved symptoms. Twelve patients’ initial ischemic colon wall and mucous were essentially recovered; the appearance of four patients’ colon wall mucous was normal. This suggests that symptoms disappear quickly and that lesions recover quickly after blood supply is improved. This fast recovery distinguishes ischemic enterocolitis from other inflammatory and non-specific intestinal diseases.

Because the local lumen was slim, biopsies were performed to rule out spasm causes, and the results showed that there was fibrous connective tissue hyperplasia in the biopsied tissue. Therefore, it is believed that the narrowing of the lumen was closely related to fibrous connective tissue hyperplasia. Pathologically, fibrous connective tissue hyperplasia in tissue reflects long-term ischemia. Whether or not the narrowing of the lumen is caused by fibrous connective tissue hyperplasia needs further observations. Eighty percent of ischemic enterocolitis patients are older than 50[8-11]. It is believed that the incidence of cardiovascular disease increases in the elderly. This results in a number of conditions, including hypertension with vascular degeneration, organic heart lesions leading to arrhythmia which produces thrombus, and thrombi exfoliation causing embolism. All 16 patients in this study were older than 50 and had a history of cardiovascular disease. Ten cases had long-standing symptoms due to hyper-tension and coronary heart disease. In those 10 patients, one was hospitalized for subventricular-wall infarction, and the other six patients’ cardiogram showed auricular fibrillation and conduction blocks. To explore whether there was a cause and effect relationship between cardiovascular disease and ischemic enterocolitis, DSA and selective mesenteric inferior angiography were performed in 14 patients with long-term cardiovascular disease. Results showed that three cases had mesenteric amphraxis inferior and the formation of the collateral circulation. There were different degrees of stenosis in the other 11 subjects’ mesenteric inferior cavities which grew slim and their branches were stenotic, so the radiographic image was not complete and the ends of some branches even cannot be seen. Thus, it is believed that the development of angiography, especially of selective mesenteric inferior angiography, can make intestinal ischemia diagnoses quicker and easier [12-15]. The aged cardio-vascular patients are high-risk population for ischemic enterocolitis. It is established that thrombi exfoliation is the direct cause of embolism. Therefore, it is well-established that cardiovascular disease has direct relationship with this disease.

The mesenteric inferior artery descends from the abdominal aorta at an acute angle. This angle is smaller than the angle at which the mesenteric superior artery comes from abdominal aorta, making the mesenteric inferior artery nearly parallel to the abdominal aorta. Though the mesenteric inferior artery is thinner than mesenteric superior artery, the thrombus coming from thoracic aorta in blood can easily enter mesenteric inferior artery. Blood supply to the left part of colon mainly comes from mesenteric inferior artery. Because of its size and location, the thrombus blocks the primary mesenteric inferior artery and related branches, leading to ischemia in different parts of intestine. The anatomical characteristic of this set of blood vessels is essential to explain why ischemic enterocolitis frequently occurs on the left part of colon. It is, therefore, believed that selective mesenteric inferior angiography is not only effective for diagnosis, but will also prove helpful to providing etiological evidence for the disease.