Evaluating the CT diagnosis of Clostridium difficile colitis: should CT guide therapy?

Clostridium difficile infection in the intensive care unit

Clostridium difficile infection (CDI) is becoming more common worldwide. The morbidity and mortality associated with C difficile is also increasing at an alarming rate. Critically ill patients are at particularly high risk for CDI because of the prevalence of multiple risk factors in this patient population. Treatment of C difficile continues to be a difficult problem in patients with severe or recurrent disease. This article seeks to provide a broad understanding of CDI in the intensive care unit, with special emphasis on risk factor identification, treatment options, and disease prevention.

Clinical review of the management of fulminant clostridium difficile infection

BACKGROUND

Clostridium difficile infection (CDI) is a frequent cause of morbidity and mortality among elderly hospitalized patients. A small but increasing number of patients have developed fulminant CDI, and a significant number of these patients require emergency colectomy. In this review, we discuss the risk factors, pathophysiology, diagnosis, and management of fulminant CDI.

DATA SOURCES

A literature search (Medline, Embase, Cochrane Library, Biosis, Science Citation Index, Ovid Journals) was performed from the period between January 1980 and June 2008 using the key words "Clostridium difficile,""pseudomembranous enterocolitis,""colectomy,""acute abdomen,""antibiotic-associated diarrhea," or "fulminant Clostridium difficile colitis." Articles not in English or not related to human subjects were excluded. For this review, we analyzed the articles identified in our original search and those articles cited in the original review articles. No randomized trials were found on the surgical management of fulminant CDI and only retrospective studies with a minimum of five patients were used in the review. With respect to medical treatment, we based our review on guideline articles, systematic reviews, and available randomized trials.

CONCLUSION

Both the incidence and severity of CDI are increasing. Fulminant CDI is underappreciated as a life-threatening disease because of a lack of awareness of its severity and its nonspecific clinical syndrome. Early diagnosis and treatment are essential for a good outcome, and early surgical intervention should be used in patients who are unresponsive to medical therapy. The surgical procedure of choice is a total abdominal colectomy with end ileostomy, although the mortality rate remains high.

The acute abdomen in the immune compromised host

Recent advances in transplantation, oncology and AIDS therapy have greatly increased life expectancies of patients diagnosed with malignancy, auto-immune disorders and organ failure. However, as this immune compromised population grows, complications of such therapies have become a major source of morbidity and mortality. Classical clinical and laboratory evidence of intra-abdominal pathology may be absent in the immune compromised host. Consequently, the radiologist is increasingly called upon to diagnose acute intra-abdominal complications associated with immunodeficiency. This review explores the aetiology of the acute abdomen in the immune compromised host. The typical radiological appearances of the commonest conditions are illustrated. The challenges and limitations in the radiological diagnosis of these conditions are discussed.

Radiologic findings in taxane induced colitis

Ischemic colitis in breast cancer patients being treated with taxane-based chemotherapy, which may lead to serious morbidities and even death, has recently been defined as a clinical entity. The purpose of this retrospective study was to evaluate the computed tomography (CT) findings in taxane-related colitis and determine their clinical relevance. CT scans of 41 patients at risk for taxane colitis were reviewed retrospectively for bowel and peritoneal abnormalities. Morphological findings were analyzed and correlated with clinical, pathological, and endoscopic findings. CT scans in 10 of the 41 patients showed a definitely abnormal colon with a thickened wall or distended with fluid, signs that are suggestive of colitis, in the context of the clinical picture. Radiographic changes in patients with taxane colitis are not specific but, in the appropriate context, can suggest the correct diagnosis and guide the patient's management.

CT imaging of colitis

Computed tomography (CT) is widely used to assess patients with nonspecific abdominal pain or who are suspected of having colitis. The authors recommend multidetector CT with oral, rectal, and intravenous contrast material and thin sections, which can accurately demonstrate inflammatory changes in the colonic wall and help assess the extent of disease. In most cases, the final diagnosis of the type of colitis is based on clinical and laboratory data and colonoscopic and biopsy findings, but specific CT features help narrow the differential diagnosis. Ulcerative colitis is distinguished from granulomatous colitis (Crohn disease) in terms of location of involvement, extent and appearance of colonic wall thickening, and type of complications. Ulcerative colitis and Crohn disease (granulomatous colitis) are rarely associated with ascites, which is often seen in infectious, ischemic, and pseudomembranous colitis. Pseudomembranous colitis also demonstrates marked wall thickening and, occasionally, skip areas but is associated with broad-spectrum antibiotic treatment or chemotherapy. Neutropenic colitis is characterized by right-sided colonic and ileal involvement, whereas ischemic colitis is characterized by vascular distribution pattern and history. Diverticulitis is a focal asymmetric process with fascial thickening and inflamed diverticula. Dilatation of a thick-walled appendix with increased enhancement and adjacent stranding suggests appendicitis, but inflammatory changes may extend to the cecum and terminal ileum. Epiploic appendagitis is a focal rim-enhancing area next to the colon, usually without any substantial colonic wall thickening.

Colonic abnormalities on CT in adult hospitalized patients with Clostridium difficile colitis: prevalence and significance of findings

OBJECTIVE

The purpose of this study was to determine the prevalence of an abnormal colon on CT in adult inpatients with Clostridium difficile colitis, compare the clinical presentation of these patients, and determine whether CT findings predicted the need for surgical treatment.

MATERIALS AND METHODS

Over a 21-month period, 152 of 572 inpatients with C. difficile colitis were identified and had CT scans performed within 2 weeks of the diagnosis. These were independently and retrospectively reviewed by two reviewers. Those with colonic wall thickness greater than 4 mm were considered positive (CT-positive patients) and were further reviewed for specific findings in the colon. All 152 patients with CT scans were also retrospectively reviewed using the hospital information system for certain clinical parameters, admitting diagnoses, and reasons for scanning. The following were compared using several statistical tests: clinical parameters in CT-positive and CT-negative patients and surgical and nonsurgical groups to determine if positive scans or surgical treatment could be clinically predicted; specific CT findings in CT-positive patients to see if an association was found with clinical parameters or surgical treatment; and admitting diagnoses and reasons for scanning in scanned and unscanned populations to see which patients were more likely to undergo CT.

RESULTS

Seventy-six (50%) of 152 scanned hospitalized patients with C. difficile colitis were CT-positive. These patients most often had segmental involvement (50 [66%] of 76 patients), with the rectum (60 [82%] of 73 patients) and sigmoid colon (61 [82%] of 74 patients) most often affected. Positive scans were associated with increased WBC, abdominal pain, and diarrhea. Patients with signs and symptoms of infection or abdominal complaints were more likely to be scanned. No statistical correlation was found between specific CT findings and clinical parameters or clinical parameters and patients requiring surgery. There was no predictive value of specific CT findings for surgical treatment.

CONCLUSION

Half of the patients scanned had an abnormal CT, with segmental colonic disease more common than diffuse. Positive scans were more likely in patients with leukocytosis, abdominal pain, and fever. Specific CT findings did not correlate with clinical parameters and could not predict surgical treatment.

Pseudomembranous colitis revisited: spectrum of imaging findings

In recent years there has been a marked increase in the incidence of pseudomembranous colitis (PMC). PMC is more common in patients over 65 years of age and can cause significant morbidity. The purpose of this article is to review the imaging features of PMC on plain radiography, sonography, computed tomography (CT), scintigraphy and magnetic resonance imaging (MRI). It is important to recognize the imaging findings of PMC using different imaging methods and encourage urgent confirmation of the diagnosis serologically, as the differential includes other fulminant colitides for which colectomy may be the required. Awareness of the spectrum of imaging findings of PMC can help radiologists make the primary or incidental diagnosis of PMC.

The outcome of surgery in fulminant Clostridium difficile colitis

BACKGROUND

The clinical presentation of Clostridium difficile infection ranges from asymptomatic carriage, colitis with or without pseudomembranes, to fulminant colitis. Although not common, fulminant C. difficile colitis can result in bowel perforation and peritonitis with a high mortality rate. Colectomy is often indicated in these cases.

METHODS

We retrospectively analysed the outcome of 14 patients who underwent surgery for fulminant C. difficile colitis in the period 1996-2003 in our Unit.

RESULTS

The indications for surgery were systemic toxicity and peritonitis (n = 10), radiological and clinical evidence of progressive toxic colonic dilatation (n = 3) and progressive colonic dilatation with bowel perforation (n = 1). C. difficile infection as the cause of colitis was diagnosed pre-operatively in seven (50%) patients, six of whom underwent a total colectomy and one a right hemicolectomy. Overall mortality in our series was 35.7%. Total colectomy was associated with a lower mortality rate of 11.1% (1/9) when compared with left hemicolectomy was 100% (4/4) (P = 0.01). One patient who underwent a right hemicolectomy (on the basis of deceptively normal external appearance of the rest of the colon intra-operatively) survived after a prolonged hospital stay.

CONCLUSIONS

Early or pre-operative microbiological diagnosis of C. difficile infection can be difficult in patients with a fulminant presentation. Those patients with C. difficile colitis, who develop signs of toxicity, peritonitis or perforation, should undergo a total colectomy as the operation of choice.

Gastrointestinal complications in the neutropenic patient: characterization and differentiation with abdominal CT

PURPOSE

To characterize the computed tomographic (CT) findings of gastrointestinal complications in neutropenic patients and to identify CT features that can help differentiate these complications.

MATERIALS AND METHODS

Abdominal CT scans obtained during a 6-year period were reviewed retrospectively to identify 76 neutropenic patients with radiologic bowel abnormalities. Scans were analyzed for wall thickening, pneumatosis, wall nodularity, mucosal enhancement, bowel dilatation, ascites, and mesenteric stranding. The location and extent of abnormalities were noted. Independent chart and pathology report reviews were used to determine the patients' final diagnoses: neutropenic enterocolitis (n = 53), Clostridium difficile colitis (n = 14), graft-versus-host disease (n = 7), cytomegaloviral colitis (n = 1), and ischemic bowel (n = 1). Results were assessed with the Student t test for quantitative wall thickness and the chi2 test for the number of patients with each diagnosis who demonstrated each CT finding.

RESULTS

Mean bowel wall thickening was greatest in C difficile colitis (12 mm) and least in graft-versus-host disease (5 mm). Pneumatosis was limited to neutropenic enterocolitis (21% [11 of 53 patients]) and bowel ischemia. Wall nodularity was significantly more common (P <.01) in C difficile colitis (36% [five of 14 patients]). In graft-versus-host disease, the rates of mucosal enhancement and bowel dilatation were highest (P <.05) (71% [five of seven patients] and 86% [six of seven patients], respectively). In C difficile colitis, the rates of ascites and mesenteric stranding were highest (57% [eight of 14 patients] and 71% [10 of 14 patients], respectively). Although findings in neutropenic enterocolitis and graft-versus-host disease could involve any bowel segment, C difficile colitis was always limited to the colon.

CONCLUSION

Several CT findings can help differentiate specific gastrointestinal complications in neutropenic patients.

Diseases of the cecum: a CT pictorial review

Cecal pathology is commonly encountered and may represent a diagnostic challenge in patients with either acute or chronic clinical presentations. Although appendicitis accounts for the majority of surgical conditions presenting with right lower quadrant pain, readers should be aware of the broad spectrum of cecal pathologies and characteristic CT findings, which can be useful in establishing the correct diagnosis.

Clostridium difficile

Clostridium difficile is the most commonly identified infective cause of antibiotic associated diarrhoea. Broad spectrum antibiotics, are most frequently incriminated, although short (<3 day) antibiotic courses cause fewer episodes. Gold standard cell-culture based cytotoxin assays have been compared to rapid immunoassays, which are less effective, especially since toxin A negative, toxin B positive strains have been shown to be truly virulent. Details of colonization and adherence mechanisms have been revealed, and clonal spread has been demonstrated. The mainstay of treatment of C. difficile infection remains metronidazole. Justified fears over resistance are leading to development of alternative therapeutic strategies. These include a toxin binding polymer and ongoing biotherapy research. An antibody rise to toxin A during an episode of C. difficile diarrhoea protects against recurrence, and trials are in progress to investigate immunization: a toxoid vaccine which is immunogenic and safe in healthy volunteers shows promise for the future.