Ischemic colitis

Ischemic Proctitis: Case Series and Literature Review

Ischemic injury to the rectum is rare owing to its rich vascular supply, and is seldom seen in clinical practice. Risk factors include major vascular occlusive disease, disruption of collateral circulation, and low flow state. It is of paramount importance to diagnose this entity early in its course. Although CT scan can suggest the diagnosis and identify other causes of clinical deterioration, colonoscopy remains the key test in diagnosing and determining the extent of ischemic change. Endoscopic findings and the overall clinical picture determine patient management. Treatment is nonoperative for nongangrenous ischemic proctocolitis, whereas surgery is necessary for gangrenous, transmural rectal ischemia. Over a 20-year period, a retrospective review of cases of acute rectal ischemia were analyzed. Aortoiliac occlusive disease accounted for nearly one-half the cases (7/15), and 40 per cent (6/15) was secondary to a low flow state. In our series, two-thirds of the cases involved transmural necrosis of the rectal wall (40% mortality) and the remaining one-third presented with patchy ischemic changes (20% mortality).

Increased activity and expression of gelatinases in ischemic colitis

Ischemic colitis results from insufficient blood supply but its pathogenesis is poorly understood. The aim of this study was to determine whether the activity and expression of gelatinases (MMP-9 and MMP-2) are increased in the colonic mucosa of patients with ischemic colitis. MMP-9 and MMP-2 activity and expression were assessed in colonic mucosal specimens from 8 patients with acute ischemic colitis and in 12 controls with a normal colonoscopy. The activity and expression of MMP-9 and MMP-2 were quantified in tissue samples by zymography and western blot, respectively. Colonoscopy was repeated 12 weeks after discharge in two patients and MMP activity was assessed in the slight residual mucosal changes of ischemic colitis. In patients with ischemic colitis, a significant increase in total MMP-9 and MMP-2 activity and expression was found in ulcerated areas compared with noninvolved sites of mucosa. Following resolution of ischemic ulcers the proteolytic activity returned to baseline levels. In addition, the colonic mucosa of controls showed MMP-2 activity, whereas the MMP-9 activity was negligible or not detected. We conclude that ischemic colitis induces increased activity and expression of MMP-9 and MMP-2 in the involved colonic mucosa. These changes may contribute to tissue degradation and remodeling of the colonic mucosa in ischemic colitis.

Fatal colonic ischemia: A population-based study

OBJECTIVES

To estimate the incidence of fatal colonic ischaemia (CI) and the cause-specific mortality of CI, and to describe the localization and extension of colonic infarction and quantify the risk factors associated with CI.

MATERIAL AND METHODS

Between 1970 and 1982 the autopsy rate in Malmö, Sweden, was 87%, creating the possibilities for a population-based study. Out of 23,446 clinical autopsies, 997 cases were coded for intestinal ischaemia in a database. In addition, 7569 forensic autopsy protocols were analysed. In a case-control study nested in the clinical autopsy cohort, four CI-free controls, matched for gender, age at death and year of death, were identified for each fatal CI case in order to evaluate the risk factors.

RESULTS

The cause-specific mortality ratio was 1.7/1000 autopsies. The overall incidence of autopsy-verified fatal CI was 1.7/100,000 person years, increasing with age up to 23/100,000 person years in octogenarians. Fatal cardiac failure (odds ratio (OR) 5.2), fatal valvular disease (OR 4.3), previous stroke (OR 2.5) and recent surgery (OR 3.4) were risk factors for fatal CI. Narrowing/occlusion of the inferior mesenteric artery (IMA) at the aortic origin was present in 68% of the patients. The most common segments affected by transmural infarctions were the sigmoid (83%) and the descending (77%) colon.

CONCLUSIONS

Heart failure, atherosclerotic occlusion/stenoses of the IMA and recent surgery were the main risk factors causing colonic hypoperfusion and infarction. Segments of transmural infarctions were observed within the left colon in 94% of the patients. Awareness of the diagnosis and its associated cardiac comorbidities might help to improve survival.

Ischemic colitis

BACKGROUND

Ischemic colitis almost always occurs in older patients. Because life expectancy is increasing, more and more often physicians will face this problem. The aim of this study was to identify factors leading to surgery in the acute phase of the disease, and to evaluate mortality and long-term follow-up evaluation.

METHODS

We performed a retrospective study of 73 patients (mean age, 73 y) in the Department of General and Digestive Surgery. Diagnosis was obtained by endoscopic and pathologic procedures. The median follow-up period was 4.5 years (range, 2-9 y).

RESULTS

Thirty-six patients had 1 or more co-existing medical diseases. All the patients had either lower intestinal bleeding (45 patients) or diarrhea (28 patients). Thirty-three patients had undergone surgery (45%). In the surgical group, 13 patients underwent immediate surgery for abdominal tenderness and/or shock. Eight of these patients died (62%). Out of 60 patients undergoing nonsurgical immediate management, 1 patient died (septic shock). Delayed surgery was indicated in 20 out of the 59 remaining patients for clinical or endoscopic aggravation. Six of these patients died (30%). Multivariate analysis selected 4 factors of severity: age younger than 80 years, male sex, absence of bleeding, and abdominal tenderness. In the follow-up period 13 patients died from a cardiovascular disease. The 2- and 5-year actuarial survival rates of patients who survived the initial hospitalization were 88% and 68%, respectively.

CONCLUSIONS

Multivariate analysis selected the risk factors of severity. In severely ill patients serial endoscopic evaluations are the best indicator for surgery before appearance of tenderness, septic shock, full-thickness gangrene, and perforation. At discharge, anticoagulant or anti-arrhythmic therapy should be considered for patients who have cardiovascular disease.

[Ischemic colitis: two forms of clinical presentation and outcome]

OBJECTIVES

To characterize the clinical presentation and outcomes of ischemic colitis in our environment with a view to identifying risk factors.

METHOD

Fifty-one patients diagnosed in our hospital with ischemic colitis over a 5-year period (1998-2002) were retrospectively analyzed. Demographic data, clinical symptoms, diagnosis and treatment were studied. Two groups (surgical patients [n = 28] and nonsurgical patients [n = 23]) were compared.

RESULTS

No significant differences between the two groups were found in demographic data and associated disease. Diagnosis was performed by colonoscopy in nonsurgical patients and by analysis of the surgical specimen in almost all surgical patients. The presenting symptom was lower gastrointestinal bleeding in nonsurgical patients (p < 0.05) and peritonism in surgical patients (p < 0.05). Mortality was significantly higher in patients older than 80 years than in younger patients.

CONCLUSIONS

Lower gastrointestinal bleeding was more common as the presenting symptom in transitory forms of ischemic colitis. An acute abdomen indicates serious forms requiring surgery. Therefore the initial clinical symptoms determine the treatment provided. Advanced age is a poor prognostic factor for ischemic colitis. Risk factors in our series were presentation as acute abdomen and advanced age.

Diagnosis and management of ischemic colitis

The clinical presentation and outcome of ischemic colitis has a wide spectrum. Impaired perfusion of blood to the bowel from a variety of causes is the underlying pathophysiology. The presence of diarrhea, abdominal pain, and mild lower gastrointestinal bleeding should prompt consideration of ischemic colitis as a cause. Although many laboratory tests and radiographic images may suggest the diagnosis, endoscopic visualization of colonic mucosa with histologic analysis of biopsies is the gold standard for identification of colonic ischemia. Most cases are transient and resolve without any complications. Medical therapy for chronic ischemia has been anecdotally proven but not carefully studied. Complications of ischemic colitis can include bowel perforation, peritonitis, persistent bleeding, protein-losing colopathy, and symptomatic intestinal strictures. Thus, surgical resection of the affected segment should be considered early to minimize adverse outcomes. This review describes the etiology, pathophysiology, clinical features, diagnostic approach, and management of ischemic colitis.

Anesthésie et réanimation pour chirurgie réglée de l'anévrisme de l'aorte abdominale

OBJECTIVES

Patient scheduled for infrarenal abdominal aortic aneurysm surgery carries a high risk of cardiac or respiratory comorbidity. To outline the perioperative management for these patients.

METHODS

Review of the literature using MesH Terms "abdominal aortic aneurysm", "anesthesia", "analgesia" "critical care" and/or "surgery" in Medline database.

RESULTS

Cardiac preoperative evaluation and management have recently been reviewed. Intermediate and high-risk patients should undergo non-invasive cardiac testing to decide between a preoperative medical strategy (using betablocker+/-statin and aspirin) and an interventional strategy (coronary angioplasty or cardiac surgery). Perioperative myocardial ischaemia should also be investigated by clinical, electrocardiographic and biologic monitoring such as plasmatic troponin Ic dosage. Specific score could also assess the respiratory failure risk preoperatively. Epidural analgesia decreases this risk. There is no evidence that a pharmacological treatment decreases the incidence of acute renal failure after aortic surgery. Endovascular repair is actually recommended for older, higher-risk patients or patients with a hostile abdomen or other technical factors that may complicate standard open repair.

Ischaemic colitis mimicking inflammatory bowel disease in a young adult receiving oral anticoagulation

Ischaemic colitis (IC) is the most frequent form of gastrointestinal ischaemia. Discrepancy between non-specific symptoms and objective findings is a hallmark of IC. Thus delay of diagnosis is common due to its often subtle and unpredictable presentation. In particular, the clinical symptoms and signs of IC can overlap with those of inflammatory bowel disease. We present a case of a young man with known factor-V-Leiden mutation in whom IC developed during effective therapy with oral anticoagulants, presenting with symptoms and endoscopic findings suggestive of inflammatory bowel disease.

Ischemic colitis: a clinical review

Ischemic colitis is the most common form of intestinal ischemia. It manifests as a spectrum of injury from transient self-limited ischemia involving the mucosa and submucosa to acute fulminant ischemia with transmural infarction that may progress to necrosis and death. Although there are a variety of causes, the most common mechanism is an acute, self-limited compromise in intestinal blood flow. Patients typically have mild abdominal pain and tenderness over the involved segment of bowel. There is usually passage of blood mixed with stool, but hemodynamically significant bleeding is unusual. Although computed tomography may have suggestive findings, colonoscopy is the procedure of choice for diagnosis. Supportive care with intravenous fluids, optimization of hemodynamic status, avoidance of vasoconstrictive drugs, bowel rest, and empiric antibiotics will produce clinical improvement within 1 to 2 days in most patients. Twenty percent of patients will have development of peritonitis or may deteriorate despite conservative management and will require surgery.

Failure of conservative management after the passage of a distal colonic "cast": report of a case

PURPOSE

The spontaneous passage per rectum of a full-thickness colon "cast" is a rare consequence of acute colonic ischemia. Previous cases have undergone surgery soon afterward because of intractable symptoms. We report a patient who was managed conservatively for 11 months but ultimately required definitive surgery.

METHODS

The clinical, radiographic, pathologic, and endoscopic findings were obtained from the case notes and compared with previously reported cases.

RESULTS

A 67-year-old obese patient underwent a Hartmann's procedure for a perforated diverticular abscess, which was reversed six months later. On the first postoperative night after the reversal, she had a brief hypotensive episode, and three weeks later passed a 21-cm, full-thickness infarcted piece of colon. She did not develop peritonitis and for 11 months experienced only mild symptoms. Under colonoscopic surveillance, the granulation tissue conduit connecting the remaining viable bowel became increasingly stenosed proximally and difficult to dilate. After three rapidly consecutive episodes of large-bowel obstruction, she required a laparotomy to resect the stricture and restore bowel continuity. From a literature review, this is the eighth case of its kind and the first in which such prolonged conservative management has been possible.

CONCLUSIONS

When symptoms permit, it is feasible to manage patients conservatively in the short-term after this unusual event to allow recovery from the initial insult and planning of future surgery. However, definitive treatment is surgical and colonoscopic management should not delay this once the patient is fit for surgery.

Bedside colonoscopy for critically ill patients with acute lower gastrointestinal bleeding

OBJECTIVE

To determine the clinical impact of bedside colonoscopy for critically ill patients with acute lower gastrointestinal (GI) bleeding.

DESIGN AND SETTING

A 3-year retrospective analysis (chart review). Medical intensive care unit (ICU) of a 1,312-bed tertiary-care center in Taiwan.

PATIENTS AND PARTICIPANTS

Fifty-five people undergoing bedside colonoscopy for lower GI bleeding that developed while in the ICU.

INTERVENTIONS

Bedside colonoscopy.

MEASUREMENTS AND RESULTS

Colonoscopy was successful in diagnosing the source of bleeding in 37 patients. Among them, colitis (15 patients, including ischemic, pseudomembranous, or radiation-induced) and acute hemorrhagic rectal ulcer (nine patients) were the most frequent confirmed causes. In seven patients, fresh blood was noticed above the colonoscopically accessible area and considered to originate from the small bowel. No adverse event was associated with colonoscopy. Spontaneous cessation of bleeding was noted in 29 (29/55, 53%) patients, whereas 16 (16/55, 29%) achieved endoscopic hemostasis. Ten (10/55, 18%) patients failed primary hemostasis or localization. Overall in-hospital mortality was 53% (29/55); however, hemorrhage-related death occurred in only two patients.

CONCLUSIONS

ICU patients with acute lower GI bleeding have distinctive causes. Bedside colonoscopy is effective for diagnosis in two-thirds of patients, but only a minority of them needs endoscopic hemostasis.

Colonic ischemia: an under-recognized cause of lower gastrointestinal bleeding

We described signs and symptoms of patients who present to an Emergency Department (ED) with intestinal ischemia and compare clinical course and outcomes of patients with mesenteric vs. colonic ischemia. We retrospectively reviewed charts of 100 patients discharged from our hospital with an ICD-9 code for mesenteric or intestinal ischemia. Compared to patients with mesenteric ischemia, those with colonic ischemia were older (61 vs. 77 years, respectively; p = 0.002), were more likely to present with gastrointestinal (GI) bleeding (11 vs. 90%, respectively; p < 0.001), but were less likely to report abdominal pain as their primary complaint (89% vs. 10%, respectively; p < 0.001) or to receive a correct ED diagnosis (75% vs. 9%, respectively; p < 0.001). Patients with colonic ischemia frequently presented with gross GI bleeding, and were often misdiagnosed in the ED. For timely treatment of a potentially serious condition, the diagnosis of intestinal ischemia should be considered in ED patients presenting with GI bleeding and appropriate risk factors.

Risk factors for colon ischemia

BACKGROUND

To identify predictors of colon ischemia, we examined demographic and clinical characteristics of patients, as well as their prior health care utilization.

METHODS

Using insurance data, we identified 700 persons at least 20-yr old with presumed colon ischemia between 1995 and 1999, and 6,440 controls. Case identification was based on diagnosis and procedure codes in insurance claims for which we used a previously reported, validated algorithm. We ascertained preceding medical diagnoses and the use of drugs and health services from the insurance claims files.

RESULTS

Patients with colon ischemia were nearly three times as likely to have IBS than controls. A history of nonspecific colitis, lower gastrointestinal tract hemorrhage, systemic rheumatologic disorders, and ischemic heart disease in the preceding 6 months, and abdominal surgery in the past month were also much more common in colon ischemia cases than controls. Use of a drug to treat diarrhea was strongly associated with risk. The most prevalent risk factor for colon ischemia was the use of drugs with a side effect of constipation, found in one-third of cases and one in nine controls. Cases had seen physicians, particularly gastroenterologists, much more commonly in the preceding 6 months than had controls.

CONCLUSIONS

Clinically evident colon ischemia arises preferentially in persons with prior abdominal complaints, many of whom carry a diagnosis of IBS. Drugs that reduce bowel motility may constitute a widespread and potentially avoidable risk factor. The frequency of preceding doctor visits, without a specific diagnosis, suggests that colon ischemia may have a prolonged subacute presentation.

N/A

N/A

Frequency and CT patterns of bowel wall thickening proximal to cancer of the colon

OBJECTIVE

This study was performed to determine the frequency and patterns of colon wall thickening seen on CT of patients with adenocarcinoma of the colon.

MATERIALS AND METHODS

Preoperative abdominal and pelvic CT scans of 185 patients with surgically proven adenocarcinoma of the colon were retrospectively evaluated by three abdominal radiologists for the presence of colon obstruction and colon wall thickening proximal to the colon adenocarcinoma. The distributions and patterns of colon wall thickening were categorized by consensus. CT findings were compared with pathologic findings. Fisher's exact test was used to determine the statistical significance of any associations.

RESULTS

Of 185 patients, CT findings of 20 (10.8%) showed colon wall thickening. Of these, the adenocarcinoma obstructed the colon in 19 patients (p < 0.01). Colon obstruction was partial in 10 patients (53%) and complete in nine (47%). Colon wall thickening was contiguous to the tumor in 14 (70%) patients and noncontiguous in six (30%). Segmental and pancolonic, patchy and diffuse, and dependent and nondependent colon wall thickening was observed in 10 patients (50%) in each category. Associated small-bowel wall thickening was shown in 10 (50%) of the 20 patients. Pathologic examination showed colon wall thickening to be due to edema in all cases.

CONCLUSION

Colon wall edema can occur proximal to colon adenocarcinoma, is almost always associated with colon obstruction, and is predominantly contiguous with the obstructing adenocarcinoma.

Occurrence of colon ischemia in relation to irritable bowel syndrome

OBJECTIVE

In November 2000, alosetron HCl (Lotronex), a treatment for irritable bowel syndrome (IBS), was removed from the U.S. market in part because of the occurrence of colon ischemia in treated patients. Since the relation between colon ischemia and IBS is poorly understood, we evaluated the incidence of colon ischemia among people with and without IBS.

METHODS

Using medical claims data from a large health care organization in the United States, we identified 87,449 people with an IBS diagnosis between January 1995 and December 1999. We calculated age- and sex-specific incidence rates in the general population and in IBS patients.

RESULTS

There were 740 cases of colon ischemia during 8.5 million person-years of observation in 5.4 million persons. The crude incidence rate was 42.8 cases per 100,000 person-years for IBS patients. By comparison, the incidence rate was 7.2 per 100,000 person-years in the general population. After adjustment for age, sex, and calendar year, the incidence of colon ischemia in people with IBS was 3.4 times higher than in persons without (95% CI 2.6-4.5).

CONCLUSIONS

Rates of colon ischemia among patients carrying a diagnosis of IBS are substantially higher than in the general population. Colon ischemia, though unusual in IBS patients, may nonetheless constitute a distinct part of the IBS natural history. Alternatively, it may be a consequence of therapy, or a manifestation of other bowel pathology that is sometimes confused with IBS.

Ischemic colitis: spectrum of disease and outcome

BACKGROUND

The aim of this study was to identify risk factors, clinical characteristics, and outcome of patients with colon ischemia.

METHODS

A 10-year (1992-2002) retrospective study was undertaken. Patients were identified from computerized hospital discharge information. Patient variables were entered into a computerized database and analyzed.

RESULTS

One hundred twenty-nine patients were identified. The mean age was 66 years (range, 29-98 years); 47% were male. Forty-three patients (33%) had chronic renal failure; 73 patients (57%) were receiving vasoactive drugs, and 72 patients (56%) had atherosclerosis. Fifty-four of 129 patients (42%) had ischemic colitis in-hospital. Fifty-six of 129 patients (43%) had melena; 49 of 56 patients (88%) survived. Forty-three of 129 patients (33%) had an acute abdomen; 22 of 43 patients (51%) died. Seventy of 129 patients (54%) were treated nonoperatively initially; the condition of 17 of 70 patients (24%) required surgery. Of 76 patients who were treated operatively, 31 patients (41%) died. Eleven patients at operation had ischemia without colon infarction or perforation; 5 of these patients (45%) died. The overall mortality rate was 29% (37/129 patients).

CONCLUSION

Ischemic colitis is associated with chronic renal failure and atherosclerosis. Patients commonly have an acute abdomen. The absence of colonic infarction does not ensure a favorable outcome. Patients who are felt to be candidates for nonoperative therapy have significant mortality rates. Mortality rates remain high, despite treatment.

Severe acute diarrhea

Acute diarrhea is commonly caused by an infection. Severe acute diarrhea warrants immediate medical evaluation and hospitalization. Indications for stool studies include fever; bloody diarrhea; recent travel to an endemic area; recent antibiotics; immunosuppression; and occupational risks, such as food handlers. Noninfectious causes include inflammatory bowel disease, radiation enteritis, and intestinal ischemia. Management of severe acute diarrhea includes intravenous fluid rehydration and empiric antibiotics. Use of antidiarrheal agents is controversial when invasive pathogens are suspected.

A case of colonic ischemia mimicking carcinoma

In this article, we describe a case of colonic ischemia masquerading as colonic carcinoma in a 75-yr-old female. Although this clinical diagnostic problem has been described before, it is rather unusual that the clinical, roentgenographical, endoscopic, and even histopathologic evaluation could not exclude carcinoma with certainty.

A case of colonic ischemia mimicking carcinoma

In this article, we describe a case of colonic ischemia masquerading as colonic carcinoma in a 75-yr-old female. Although this clinical diagnostic problem has been described before, it is rather unusual that the clinical, roentgenographical, endoscopic, and even histopathologic evaluation could not exclude carcinoma with certainty.

Cardiac sources of embolism should be routinely screened in ischemic colitis

OBJECTIVE

Potential cardiac sources of embolism may promote ischemic colitis. The aim of this study was to evaluate their role in segmental, nongangrenous ischemic colitis and to determine the usefulness of routine cardiac evaluation in patients with this disease.

METHODS

Sixty case and 60 control patients matched for age and gender were included and questioned regarding treatment and prior cardiovascular history or risk factors. Potential cardiac sources of embolism, classified as "proven" or " still debated," were screened using an electrocardiogram, rhythmic Holter monitoring over 24 h, and transthoracic echocardiography.

RESULTS

Sex ratio (male:female) was 1:2, and mean age was 70 +/- 14 yr. Case and control patients had similar drug use, prior cardiovascular history, and risk factors. A potential cardiac source of embolism was found in 26/60 case (43%), compared with 14/60 control patients (23%) (p = 0.02; OR = 2.5, 95% CI = 1.2-5.5). Excluding the "still debated," 21/60 case (35%), compared with 8/60 control patients (13%), had a "proven" cardiac source of embolism (p < 0.01; OR = 3.5, 95% CI = 1.4-8.4). Electrocardiogram alone misdiagnosed 72% of the "proven" cardiac sources of embolism, whereas the combination electrocardiogram plus Holter monitoring detected 71%, and electrocardiogram plus echocardiography 62%. Twelve of 21 case patients with at least one proven cardiac source of embolism, were previously unknown. Anticoagulant therapy was required in 32% of case patients and antiarrhythmic therapy in 25% of cases.

CONCLUSIONS

Potential cardiac sources of embolism were more common in patients with segmental, nongangrenous ischemic colitis than in control patients. Therefore, these patients should undergo a routine electrocardiogram, rhythmic Holter monitoring, and transthoracic echocardiography. Anticoagulant therapy should also be considered for this patient population.

Diagnosis and management of intestinal ischaemic disorders

Although intestinal ischaemia is an infrequent event, early recognition and appropriate treatment can reduce the potential for a devastating outcome

Incidence of colonic ischemia, hospitalized complications of constipation, and bowel surgery in relation to use of alosetron hydrochloride

OBJECTIVE

Alosetron hydrochloride (Lotronex), a potent selective 5-hydroxytryptamine(3) receptor antagonist, was approved in February, 2000 in the United States for the treatment of diarrhea-predominant irritable bowel syndrome (IBS) in women. Marketing was suspended in November, 2000, after reports of colonic ischemia and serious complications of constipation. We sought to compare the incidence of colonic ischemia, hospitalized complications of constipation, and bowel surgery among alosetron users and a cohort of patients with IBS who did not use alosetron.

METHODS

We sought outcomes of colonic ischemia, hospitalized complications of constipation, and bowel surgery in 3,631 Lotronex users and 2,480 comparison IBS subjects using diagnoses, procedures, and drugs recorded in the UnitedHealthcare insurance claims database, and validated these by chart review. The initial assessment was to last for 3 yr beginning with the start of alosetron treatment and was to include 10,000 Lotronex users; however, the observation period ended by December 31, 2000, after suspension of marketing.

RESULTS

There were 3631 alosetron users among members of UnitedHealthcare from March through December, 2000, and we identified 2480 comparison IBS-only patients; follow-up time averaged about 5 months in both groups. There were no instances of colonic ischemia in either cohort. Thirty instances of bowel surgery occurred, giving rates of 10.2/1000 person-yr in the alosetron cohort and 11.8/1000 person-yr in the IBS/no alosetron cohort. There were three cases of hospitalized complications of constipation. The incidence rates were essentially the same in alosetron users (1.24/1000 person-yr) and in IBS patients with no alosetron use (0.92/1000 person-yr).

CONCLUSIONS

Alosetron users did not differ from IBS patients not using alosetron in the incidence of bowel surgery or hospitalized complications of constipation; there were no cases of colonic ischemia. The statistical upper limit of colonic ischemia rates in alosetron users was 2.28/1000 person-yr. Because of the market withdrawal, the size of the cohort and the duration of follow-up were smaller than originally planned; consequently, the statements about the safety of alosetron were necessarily limited. On June 7, 2002, the Food and Drug Administration approved alosetron for reintroduction in the U.S. market for women with severe diarrhea-related IBS.

Mesenteric ischaemia in haemodialysis patients: a case/control study

BACKGROUND

Mesenteric ischaemia is not uncommon in dialysis patients and seems to have been increasing in the last decade. However, the risk factors for mesenteric ischaemia are unclear and prognosis of patients after this type of ischaemic accident is not well defined.

METHODS

From January 1988 to June 1999, 15 haemodialysis patients (0.3% per patient-year) from a single institution presented with mesenteric ischaemia and the clinical, biological and radiological aspects of the ischaemia were described. To identify risk factors for mesenteric ischaemia, each ischaemic patient (case) was matched with two other haemodialysis patients not having ischaemia (controls). Survival curves were then established for the two groups.

RESULTS

A marked hypotensive episode was present in seven out of 15 case patients (47%) during dialysis sessions that preceded mesenteric ischaemia. Abdominal pain, guarding, fever and hyperleucocytosis were all present in 13 out of 15 patients (87%). An abdominal computerized tomography scan with opaque enema enabled a rapid diagnosis for six patients. The caecum was the most frequently (47%) affected segment. Twelve patients were surgically treated and the remaining three were given medical support. The two groups (case and control) were not different in cardiovascular risk factors, comorbidity, administered drugs or main haemodialysis characteristics. The median survival of the case group was 600 days, whereas 80% of the control group survived beyond this period (P=0.0132). Eleven case patients survived >3 months after mesenteric ischaemia and had a median survival of 1500 days, which was identical to their matched control patients.

CONCLUSIONS

Mesenteric ischaemia should be systematically suspected in patients experiencing abdominal pain during or after dialysis sessions. Prompt diagnosis and treatment usually allow for a favourable prognosis.

Ischaemic colitis

The term colonic ischaemia was first coined approximately 40 years ago. Up until that point, the disease was only diagnosed in cases where the colon was completely gangrenous. In the 1960s reversible non-transmural ischaemia of the colon was described and much has been written about the disease since. Ischaemic colitis is usually a disease process that is seen in the elderly. However, the true incidence of the disease remains unknown since many cases are probably never diagnosed. We now know that the disease can occur both with occlusive and non-occlusive vascular disease, the latter being much more common. Although factors that contribute to non-occlusive disease have been identified, often the exact pathophysiology is unclear and this is an area where further research is needed. Known facts about the pathophysiology and aetiology of the disease will be discussed in this chapter. The key to diagnosis is often a high degree of clinical suspicion. Various diagnostic modalities are described, but colonoscopy remains the main instrument of accurate diagnosis. Fortunately the majority of patients will have self-limiting disease and, accordingly, they usually respond to conservative therapy. When the disease progresses to transmural infarction, surgery is required and the prognosis is guarded. Since many of the patients are elderly with other underlying diseases, it is unlikely that major treatment advances will allow us to significantly alter the prognosis in this group of patients with transmural ischaemia.

Role of acquired and hereditary thrombotic risk factors in colon ischemia of ambulatory patients

BACKGROUND & AIMS

Hypercoagulable states may play an important role in the pathogenesis of colon ischemia. Aim of this study was to assess this hypothesis investigating the role of acquired and hereditary thrombotic risk factors in patients with definite diagnosis of colon ischemia.

METHODS

We compared the frequency of antiphospholipid antibodies, protein C, protein S, and antithrombin deficiencies, factor V Leiden, prothrombin gene mutation G20210GA, and methylenetetrahydrofolate reductase C677T in 36 patients (23 men, 13 women; mean age, 64.8 years) with colon ischemia, 18 patients with diverticulitis, and 52 healthy controls.

RESULTS

The prevalence of antiphospholipid antibodies was significantly higher in patients with colon ischemia compared with inflammatory and healthy controls (19.4% vs. 0% and 1.9%). Among genetic factors, only factor V Leiden was significantly associated with colon ischemia (22.2% vs. 0% and 3.8%). A combination of thrombophilic disorders was found in 25% of the cases. Overall, one or several prothrombotic abnormalities were present in 26 patients (72%).

CONCLUSIONS

A comprehensive thrombophilic screening in colon ischemia reveals a congenital or acquired thrombophilic state in 72% of patients. Hereditary and acquired thrombotic risk factors may play an important role in the disease pathogenesis.

Ischemic colitis in young adults: a single-institution experience

Ischemic colitis is not well characterized in the young adult population, despite its commonness in older patients. The aim of this study was to investigate the demographics, etiology, clinical features, and prognosis of ischemic colitis in young adults. We conducted a retrospective study of 39 young adults (<50 years of age) diagnosed with ischemic colitis over a period of 9 years (1990 to 1998). The mean age at diagnosis was 38 +/- 2 years (range 18 to 49 years); the female:male ratio was 1.8. Fifty-two percent (13 of 25) of women were using oral contraceptives at the time of diagnosis. Other potential associations identified were vascular thromboembolism (4 of 39), vasoactive drugs (4 of 39), hypovolemia (4 of 39), and vasculitis (2 of 39); 19 patients (49%) had no identifiable predisposing factors. Dominant presenting symptoms were abdominal pain (77%), bloody diarrhea (54%), and hematochezia (51%). Most patients were diagnosed at colonoscopy, and most disease was left sided. Twenty-nine patients were successfully managed with intravenous fluids, broad-spectrum antibiotics, and bowel rest; 10 patients required surgery. There was one disease-related death in the operative group. We found a strong female predominance and an association with oral contraceptive use, but almost half of the patients did not have an identifiable etiology. Mortality from ischemic colitis in this patient population is low.

Gastrointestinal problems in the chronically critically ill patient

In summary, a variety of gastrointestinal processes may occur in the chronically critically ill patient population, usually as consequence of the primary systemic process. The clinical presentation is frequently nonclassic and there often is a substantial delay in diagnosis, resulting in increased morbidity and mortality.

Ischemic colitis with atypical reactive changes that mimic dysplasia (pseudodysplasia)

OBJECTIVE

To describe reactive or reparative but atypical epithelial changes that occur in ischemic colitis.

DESIGN

Surgical pathology files were searched for the diagnosis "ischemia, bowel." All cases were studied for reactive or reparative atypical changes. These were characterized and correlated with clinical information.

RESULTS

Reactive atypical (pseudodysplastic) changes were found in 8 of 28 cases of ischemic bowel. The clinical history did not indicate ischemic colitis in 6 of 8 cases. In 3 cases, neutrophils in the lamina propria or acute cryptitis and crypt abscesses that suggested inflammatory bowel disease were noted.

CONCLUSION

Ischemic changes in the bowel may produce reactive epithelial changes with sufficient atypia to simulate dysplasia. These may be associated with histologic changes that simulate inflammatory bowel disease, specifically ulcerative colitis. Since in most cases even the clinician is not sure whether the patient has ischemia or inflammatory bowel disease and because histologic changes of the latter may occur in ischemic bowel, there is a danger that the atypical reactive ischemic changes could be interpreted as true dysplasia that occurs in inflammatory bowel disease.

Prognosis of ischemic colitis: comparison of color doppler sonography with early clinical and laboratory findings

OBJECTIVE

The objective of this study was to compare the value of color Doppler sonography with early clinical and laboratory findings in determining the prognosis of patients with ischemic colitis.

SUBJECTS AND METHODS

We reviewed the early clinical, laboratory, and color Doppler sonographic data of 24 patients with ischemic colitis. The patients were divided into two groups on the basis of their outcome. The first group comprised the patients with transient ischemia who recovered uneventfully, and the second group included the patients who needed surgery because of symptomatic transmural colic gangrene or colic stricture. Clinical data and laboratory values were compared with color Doppler sonographic findings including colic wall thickness, presence of stratification, and arterial flow in the bowel wall.

RESULTS

At univariate analysis, increased age (p = 0.007), leukocyte count (p = 0.030), lactate dehydrogenase level (p = 0.030), blood lactate level (p = 0.041), and absence of vascular flow in the colic wall (p<0.001) were significantly related to complicated ischemic colitis. At multivariate analysis, absence of arterial flow was the only significant predictor of complicated ischemic colitis (p = 0.002), with a sensitivity of 82%, a specificity of 92%, a positive predictive value of 90%, and a negative predictive value of 86%.

CONCLUSION

Absence of arterial flow in the wall of the ischemic colon on initial color Doppler sonography is suggestive of an unfavorable outcome and is more closely associated with outcome than early clinical and laboratory findings.

Segmental wall thickening in the colonic loop distal to colonic carcinoma at CT: importance and histopathologic correlation

PURPOSE

To determine the importance of the finding of segmental wall thickening in the colonic loop distal to colonic carcinoma at computed tomography (CT) by means of histopathologic correlation.

MATERIALS AND METHODS

Thirteen consecutive patients whose helical CT scans showed segmental wall thickening (>1 cm in maximal width, >5 cm in length) in the colonic loop distal to colonic carcinoma were included. The thickness and length of an involved segment, location, morphologic tumor type, CT patterns of wall thickening, and pericolic changes were evaluated. Surgical pathologic findings in all 13 patients were correlated with CT findings.

RESULTS

The involved segment distal to the colonic carcinoma showed circumferential wall thickening with a preserved wall layer pattern at CT. Pericolic changes of varying degrees were seen in 10 patients. Histopathologic examination revealed submucosal and subserosal edema (n = 6), chronic inflammation and fibrosis (n = 5), or both (n = 1), and no histopathologic alteration (n = 1). The tumors were mostly fungating (n = 11), larger than 5 cm in the greatest dimension (n = 12), located in the ascending colon (n = 10), and extended to pericolic adipose tissue (n = 11).

CONCLUSION

Colonic carcinoma, especially a large fungating type involving the ascending colon with pericolic infiltration, can produce segmental wall thickening in the distal segment at CT, which represents edema or colitis at histopathologic examination.

Cecal necrosis: infrequent variant of ischemic colitis. Report of five cases

PURPOSE

Spontaneous nonocclusive ischemic colitis involving only the right colon is an infrequent occurrence. Because this problem is less recognized than its counterpart involving the left colon, the correct diagnosis may not be considered. The purpose of this article was to describe the presentation and management of this unusual clinical problem.

METHODS

Five cases of nonocclusive ischemic cecal necrosis are described. Four of the patients presented with right-sided abdominal pain, tenderness, and leukocytosis. The preoperative diagnosis was incorrect in all patients, although cecal necrosis was considered in one. Two patients were thought to have. appendicitis, two were thought to have carcinoma, and one was thought to have a perforated viscus. Each patient underwent a right hemicolectomy and four survived.

RESULTS

Each of the patients had ischemic cecal necrosis without evidence of emboli or vasculitis. Although cecal gangrene may occur after systemic hypotension, no such event preceded these patients' presentation. We believe that the patients we treated had a form of nonocclusive ischemic colitis, which occasionally affects only the right colon.

CONCLUSION

Ischemic necrosis of the cecum is an infrequent variant of ischemic colitis that should be considered in the differential diagnosis of the elderly patient presenting with right lower quadrant pain.