Hemorrhagic necrosis of the gastrointestinal tract and its relation to cardiovascular status

Acute hemorrhagic rectal ulcer syndrome: Comparison with non-hemorrhagic rectal ulcer lower gastrointestinal bleeding

OBJECTIVE

The aim of this study was to describe the clinical characteristics of acute hemorrhagic rectal ulcer (AHRU) and to elucidate its predictive factors.

METHODS

The medical records of patients with AHRU were retrospectively reviewed. Their baseline clinical characteristics were compared with those of patients with non-AHRU lower gastrointestinal bleeding to identify predictive factors for AHRU.

RESULTS

Among the 118 patients who underwent emergency endoscopy due to acute massive hematochezia from 2013 to 2015, 25 (21.2%) were diagnosed as having AHRU. Of them, 22 (88.0%) were successfully managed endoscopically and 3 (12.0%) underwent surgery. Six (24.0%) patients developed rebleeding within 1-9 days after the initial bleeding, which was controlled by a repeat endoscopy. Five (20.0%) died during follow-up. A multivariate-adjusted logistic regression analysis revealed that a lower serum albumin level, worse Eastern Cooperative Oncology Group (ECOG) performance status and history of constipation were significant factors for predicting AHRU. Hypoalbuminemia (<30 g/L) had a sensitivity, specificity and positive and negative predictive values of 84.0%, 78.5%, 51.2% and 94.8% for predicting AHRU, respectively.

CONCLUSIONS

Approximately 20% of patients with massive hematochezia had AHRU. Most patients with AHRU can be managed endoscopically. Low serum albumin level, poor ECOG performance status and prior constipation could be used in distinguishing patients with and without AHRU, facilitating the selection of optimal bowel preparation method for massive hematochezia.

Risk Factors and Management for Massive Bleeding of an Acute Hemorrhagic Rectal Ulcer

An acute hemorrhagic rectal ulcer (AHRU) is considered to be a potentially life-threatening illness requiring urgent identification and management because of massive bleeding. It is therefore important to clarify the factors associated with the massive bleeding of an AHRU and the best management. The factors associated with the massive bleeding of 14 patients with AHRU were determined by comparing the clinicopathologic features, laboratory data, and treatment between four patients with more transfusions (≥12 U) and 10 patients with less transfusions (≤3 U). Patients with AHRU of the more transfusion group had lower performance status (PS), more diabetes mellitus, more comorbid diseases, and lower serum albumin concentrate than those of the less transfusion group. More surgical treatment and the administration of hemostatic agents were necessary for the patients with AHRU of the more transfusion group than for those of the less transfusion group, and the duration from bleeding to hemostasis in patients with AHRU of the more transfusion group was larger than that of the less transfusion group. Patients with AHRU of the more transfusion group had a longer duration of no oral food intake, total parenteral nutrition, and hospital stay from bleeding day than those of the less transfusion group. Thus, the factors associated with the massive bleeding of AHRU were identified.

Current theories of pathogenesis and treatment of nonocclusive mesenteric ischemia

Nonocclusive mesenteric ischemia (NOMI) is a poorly understood condition marked by progressive intestinal ischemia leading to infarction, sepsis, and death in a high proportion of patients. The mortality rate for this intestinal disorder remains high, even when the diagnosis is made early in the disease course. This paper presents a comprehensive review of NOMI with a detailed discussion of its history, pathophysiology, diagnosis, and treatment.

Is the gut an athletic organ? Digestion, absorption and exercise

Digestion is a process which takes place in resting conditions. Exercise is characterised by a shift in blood flow away from the gastrointestinal (GI) tract towards the active muscle and the lungs. Changes in nervous activity, in circulating hormones, peptides and metabolic end products lead to changes in GI motility, blood flow, absorption and secretion. In exhausting endurance events, 30 to 50% of participants may suffer from 1 or more GI symptoms, which have often been interpreted as being a result of maldigestion, malabsorption, changes in small intestinal transit, and improper food and fluid intake. Results of field and laboratory studies show that pre-exercise ingestion of foods rich in dietary fibre, fat and protein, as well as strongly hypertonic drinks, may cause upper GI symptoms such as stomach ache, vomiting and reflux or heartburn. There is no evidence that the ingestion of nonhypertonic drinks during exercise induces GI distress and diarrhoea. In contrast, dehydration because of insufficient fluid replacement has been shown to increase the frequency of GI symptoms. Lower GI symptoms, such as intestinal cramps, diarrhoea--sometimes bloody--and urge to defecate seem to be more related to changes in gut motility and tone, as well as a secretion. These symptoms are to a large extent induced by the degree of decrease in GI blood flow and the secretion of secretory substances such as vasoactive intestinal peptide, secretin and peptide-histidine-methionine. Intensive exercise causes considerable reflux, delays small intestinal transit, reduces absorption and tends to increase colonic transit. The latter may reduce whole gut transit time. The gut is not an athletic organ in the sense that it adapts to increased exercise-induced physiological stress. However, adequate training leads to a less dramatic decrease of GI blood flow at submaximal exercise intensities and is important in the prevention of GI symptoms.

An experimental study on the pathogenesis of acute haemorrhagic enteropathy--significance of congestion and endotoxaemia

To clarify the pathogenesis of acute haemorrhagic enteropathy, the present study was undertaken using the ileum of rats. The ligation of marginal veins of the ileum or the injection of endotoxin to the intact rats induced only slight mucosal haemorrhage. On the other hand, the injection of endotoxin into rats with ligation of the marginal veins led to severe mucosal haemorrhage. The severe mucosal haemorrhage was markedly inhibited by suppression of the production of bradykinin. These experimental results suggest that some cases of acute haemorrhagic enteropathy may be induced by the co-existence of endotoxaemia and congestion of the intestine. Thus, the mechanism of severe mucosal haemorrhage may be as follows: bradykinin, induced by endotoxin, acts to dilate capillaries and small veins in the mucosa and markedly increases their permeability.

Isolated ischemic necrosis of the cecum in patients with chronic heart disease

Isolated ischemic necrosis of the cecum is an infrequently described entity. We report three cases seen at our institution within a three-year period. All three patients had been hospitalized for congestive heart failure in the past, but none was in failure at the time of the most recent hospitalization. All three patients presented with clinical and laboratory findings consistent with acute appendicitis. At surgery the cecum was ischemic in each case, while the appendix and the remainder of the intestine appeared normal. There was no evidence of major vascular occlusion or embolization at the time of original operation. We propose that the cecum, like the splenic flexure, is a "watershed area," with poor blood supply relative to that of the adjacent intestine. While cecal ischemia has been described in association with a variety of clinical entities, we propose a newly recognized association with poor myocardial function. In such patients, isolated ischemic necrosis of the cecum should be considered in the differential diagnosis of right lower quadrant pain.

Diagnosis and outcome of bowel infarction on an acute medical service

Twenty patients with surgically or pathologically documented bowel infarction are compared with seven patients who were believed to have bowel infarction but had negative findings at laparotomy. The presentation of verified bowel infarction was nonspecific; abdominal pain, tenderness, and distension were the most common, occurring in 15 patients. No physical finding or laboratory test distinguished bowel infarction from mimicking conditions. Patients in both groups had an extremely poor prognosis. An approach to management is suggested.

Ischemia and post-ischemic regeneration of the small intestinal mucosa. An enzyme-histochemical investigation

After ligation of the vascular arcades of the upper jejunum in rats, the ischemic damage to the intestinal mucosa and its regenerative behavior after ischemia lasting 120 minutes were investigated with histological and enzyme-histochemical methods. During the ischemic injury of the jejunal mucosa, there is rejection of hydropically swollen epithelial cells into the intestinal lumen advancing from the tip to the base of the villi without a previously detectable loss of activity of the enzymes investigated. At the end of ischemia lasting 120 minutes, there is complete destruction of the villi as well as the upper portions of the crypts. After rapid re-epithelialization of the mucosal surface by a flat epithelium, reformation of villi begins already after a 24 h period of regeneration. On the third day of regeneration, the intestinal mucosa has plump villi again. Their epithelia already show the morphological characteristics of mature enterocytes. On the other hand, enzymatic maturation of the enterocytes is only concluded between the first and second week of regeneration. An altered proliferation kinetics of the crypt epithelia due to the repair process is discussed as cause of this delayed enzymatic maturation of the enterocytes relative to the morphological differentiation. Although the intestinal mucosa has a regular villous structure again after regeneration lasting 8 days, enzyme histochemical finding in the lamina propria indicate that the process of repair is only complete here in the sixth week of regeneration.

Surgical treatment of nonocclusive mesenteric infarction

Two cases of nonocclusive mesenteric vascular disease associated with stenosis of the superior mesenteric artery are described. In one patient with congestive heart failure and atrial fibrillation treated with digitalis, the first episode after a bout of sepsis was treated supportively, but a stricture of ileum secondary to full thickness intestinal infarction resulted. His second episode required emergency ileal resection for perforation. The superior mesenteric artery was subsequently reconstructed with an aortomesenteric bypass. The second patient had segmental intestinal necrosis occurring in association with superior mesenteric artery narrowing without total occlusion. These cases emphasize the importance of awareness of nonocclusive mesenteric vascular disease occurring in individuals with narrowing of the mesenteric arteries. A variety of modes of presentation are suggested. Arteriography is essential for diagnosis and, in selected cases, for therapy.

Acute gastrointestinal bleeding during experimental hypercarbia

Experimental acute hypercarbia in dogs produced significant blood loss from the upper gastrointestinal tract, as well as from the small and large intestines. At necropsy, gross and microscopic examinations demonstrated necrotizing lesions resembled the postmortem ulcerations found in some patients with severe hypercarbia. Superior mesenteric arteriograms performed in four animals shortly after onset of hypercarbia showed abnormalities consistent with vasoconstriction. Vagal inhibition by atropine and correction of respiratior acidosis by TRIS buffer failed either to reduce the blood loss or to alter the pathologic lesions. Multiple studies of blood coagulation in the hypercarbic animals revealed no consistent changes when compared with eucarbic animals. In four animals treated with phenoxybenzamine during hypercarbia, blood loss and hemorrhagic gastrointestinal lesions were diminished, suggesting possible pathogenetic role of alpha-adrenergic stimulation. Although the mechanism is not proved, vasoconstriction secondary to adrenergic stimulation may play an important bleeding occurring with hypercarbia.

Pseudomembranous colitis

Three basic histopathological patterns which may be seen in rectal biopsies from patients with pseudomembranous colitis are described, based on a study of 29 cases. The spectrum of change is illustrated and the problems of differential diagnosis are discussed--from a non-diagnostic proctitis at one extreme to acute ischaemia at the other. In the differential diagnosis of the acute colitic, the importance of urgent rectal biopsy and a carefully taken drug history is stressed. The association of pseudomembranous colitis with pre-existing disease and antibiotic therapy is confirmed. It is suggested that these cause local mucosal damage and may trigger the first part of a local Shwartzman reaction. Capillary microthrombosis may then paly a part in producing the mucosal necrosis seen later in the disease.

The roles of intraluminal chyme and vasomotor response in the pathogenesis of non-occlusive intestinal infarcts

The purpose of this study is to clarify the role of intraluminal chyme and the splanchnic vasomotor reaction on the pathogenesis of non-occlusive intestinal infarcts. In 5 mongrel dogs, 3 types of intestinal loops were created. A cervical loop, which is a heterotopic autotransplant of a segment of intestine, contains no chyme and is disconnected from the splanchnic innervation. A Thiry-Vella loop simultaneously constructed in the abdomen is also devoid of intraluminal chyme, but is still innervated. The intestine-in-continuity possesses both splanchnic innervation and intraluminal chyme. Hemorrhagic shock was then induced and the morphological response of the three types of intestine examined. The results indicate that the cervical loop is least damaged, whereas both the Thiry-Vella loop and the intestine-incontinuity are both severely damaged. It is concluded that in the non-occlusive hemorrhagic infarction of the intestinal mucosa, the peculiar splanchnic vasomotor response plays the dominant role. The pathogenesis of non-occlusive intestinal infarcts and its clinical implications are discussed.

Ischaemic lesions of the alimentary tract

The clinical and pathological findings in 23 patients with ischaemic lesions of the alimentary tract (ischaemic enterocolitis) are described. These are compared with findings in 13 patients with occlusive thrombosis of the superior mesenteric artery. The pathological features distinguishing the two conditions are discussed. Ischaemic enterocolitis was found to be a relatively common condition (0.6% of necropsies). The occurrence of mucosal fibrosis (a hitherto undescribed feature) has been of help in the biopsy diagnosis of ischaemic lesions of the gut.

Intestinal ischemic syndromes

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