Toxic megacolon in patients with severe acute colitis: computed tomographic features

Surgical Emergencies in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) patients are at risk for undergoing emergency surgery for fulminant disease, toxic megacolon, bowel perforation, intestinal obstruction, or uncontrolled gastrointestinal hemorrhage. Unfortunately, medical advancements have failed to significantly decrease rates of emergency surgery for IBD. It is therefore important for all acute care and colorectal surgeons to understand the unique considerations owed to this often-challenging patient population.

Spectrum of CT findings in amebic colitis

Entamoeba histolytica is distributed throughout the world. Invasive amebiasis affects millions of people globally, and the associated complications cause 40,000-100,000 deaths per year. In countries where fecal-oral transmission is unusual, amebic colitis is not common, and the infection may be seen in travelers to and emigrants from endemic areas. Without adequate treatment, amebic colitis may develop into fulminant and become rapidly fatal. With the current increase in global mobility, amebic colitis should be suspected even in patients not in the endemic areas. CT plays an important role in the diagnosis of amebic colitis by demonstrating the presence of colitis with the typical involvement of the cecum and rectum. Pathological features of atypical involvement are also demonstrated. Since preoperative diagnosis can reduce the mortality associated with necrotizing colitis, radiologists need to recognize the typical as well as atypical CT findings of amebic colitis. Considering this requirement, this paper aims to describe the histopathologic features of amebic colitis and to illustrate the spectrum of corresponding CT findings.

Evaluation and management of the surgical abdomen

PURPOSE OF REVIEW

The aim of this study was to describe important features of clinical examination for the surgical abdomen, relevant investigations, and acute management of common surgical problems in the critically ill.

RECENT FINDINGS

Lactate remains a relatively nonspecific marker of gut ischemia. Dual energy computed tomography (DECT) scan can improve diagnosis of bowel ischemia. Further evidence supports intravenous contrast during CT scan in critically ill patients with acute kidney injury. Outcomes for acute mesenteric ischemia have failed to improve over time; however, increasing use of endovascular approaches, including catheter-directed thrombolysis, may decrease need for laparotomy in the appropriate patient. Nonocclusive mesenteric ischemia remains a challenging diagnostic and management dilemma. Acalculous cholecystitis is managed with a percutaneous cholecystostomy and is unlikely to require interval cholecystectomy. Surgeon comfort with intervention based on point-of-care ultrasound for biliary disease is variable. Mortality for toxic megacolon is decreasing.

SUMMARY

Physical examination remains an integral part of the evaluation of the surgical abdomen. Interpreting laboratory investigations in context and appropriate imaging improves diagnostic ability; intravenous contrast should not be withheld for critically ill patients with acute kidney injury. Surgical intervention should not be delayed for the patient in extremis. The intensivist and surgeon should remain in close communication to optimize care.

CT features of toxic megacolon: A systematic review

INTRODUCTION

Toxic megacolon is a rare but life-threatening condition. Diagnosis is made when both systemic toxicity and an enlarged colon are present. We undertook a systematic review of the literature to provide a list of toxic megacolon findings on computed tomography (CT) imaging along with the prevalence rate for each finding.

METHODS

PubMed, Embase, and Cochrane library were searched. After eligibility screening and quality assessment, the reported CT findings of toxic megacolon with their respective prevalence rates were extracted from the included studies. Pooled prevalence rates were calculated for each finding using random-effects model and inverse variance method. I² statistics were used to estimate the heterogeneity. All statistical analyses were performed using R software. P-values less than 0.05 were considered significant.

RESULTS

Database search yielded a total of 122 records. Only 2 of these studies were finally selected following two-step eligibility screening. Most common CT features of toxic megacolon and their pooled prevalence rates [95% CI] were: colonic distension (reported in 100% of patients), abnormal haustration 96% [0.75-0.99], peri-colonic fat stranding 87% [0.29-0.99], nodular pseudo polyps 76% [0.52-0.91], multilayered appearance of colonic wall 58% [0.38-0.76], and ascites 57% [0.21-0.87]. Other reported CT features: colonic wall thickening, pleural effusion, accordion sign, small bowel/gastric distension, and segmental colonic wall thinning.

CONCLUSION

and implication for practice: Colonic distension can be accompanied by 10 other findings in CT images of patients with toxic megacolon. Although these findings are not specific, toxic megacolon should be included in the list of differential diagnoses when these findings are present.

CT diagnosis of non-traumatic gastrointestinal perforation: an emphasis on the causes

Gastrointestinal tract (GI) perforations can occur due to various causes such as trauma, iatrogenic factor, infectious condition, peptic ulcer, inflammatory disease, or a neoplasm. Because GI perforations represent an emergency and life-threatening condition, prompt diagnosis and surgical treatment are required in most cases. However, according to the underlying causes of GI perforations, additional treatment strategies may be needed. Adjuvant chemotherapy or immunotherapy may be required in various GI neoplasms such as adenocarcinoma, lymphoma or gastrointestinal stromal tumor. Inflammatory bowel disease is a chronic disease repeating cycle of intermittent, thus appropriate medical treatment and periodic follow-up are also required. Moreover, vascular intervention may have a role in some cases of mesenteric ischemia associated with mesenteric artery occlusion. Recently, computed tomography (CT) has been the first choice for patients with suspected GI perforations, because CT plays an important role in the accurate assessment of the perforation site, the pathology causing the perforation and the ensuing complications. This review will illustrate characteristic CT findings that differentiate underlying pathologies causing GI perforations to help clinicians decision-making regarding an optimal treatment plan.

The effect of pre-admission immunosuppression on colectomy rates in acute severe ulcerative colitis

BACKGROUND

Patients on immunosuppression at the time of acute severe ulcerative colitis have been suggested to be at a higher risk of colectomy than those who are treatment-naïve. The aim of this study was to examine the effect of immunosuppressive therapy on the risk of colectomy.

METHOD

We conducted a retrospective observational cohort study using prospective data examining the 30 day and 1 year colectomy rates of 200 consecutive patients with an index episode of acute severe ulcerative colitis as defined by the Truelove and Witts criteria.

RESULTS

Immunosuppression on admission was shown not to increase colectomy rate at 30 days post-admission (immunomodulator: p = 0.422, oral steroids: p = 0.555). A total of 24 patients underwent colectomy between 30 days and 1 year. A three-fold higher risk of colectomy at 1 year was seen in those requiring an immunomodulator prior to the index admission compared with those started de novo during the index admission [41% versus 14% odds ratio (OR): 2.93 (1.19-7.24 p = 0.016)]. Factors most predictive of colectomy at 30 days were abdominal radiographic colonic dilation ⩾5.5 cm, first presentation of ulcerative colitis, C-reactive protein ⩾ 45 mg/l on day 3 of therapy and bowel frequency ⩾8 on day 3.

CONCLUSION

The need for an immunomodulator prior to admission with acute severe ulcerative colitis increases the medium-term colectomy rate by three-fold at 1 year. Prospective studies are needed to confirm these findings and develop strategies to reduce the high risk in this subgroup of patients.

Gastrointestinal Motility Problems in Critically Ill Patients

Gastrointestinal (GI) motility problems are common complications in critical care patients. GI problems contribute to an increased risk of morbidity and mortality. Toxic megacolon (TM) is a type of acquired megacolon categorized as a medical emergency and includes severe inflammation affecting all layers of the colon wall. The high incidence of GI complications in critically ill patients requires the critical care nurse to provide close monitoring of patients at risk and an acute awareness of the causation, signs and symptoms, and treatment of various GI motility disorders, including gastroparesis, ileus, and TM.

Nontraumatic large bowel perforation: spectrum of etiologies and CT findings

Large bowel perforation is an abdominal emergency that results from a wide range of etiologies. Computed tomography is the most reliable modality in detecting the site of large bowel perforation. The diagnosis is made by identifying direct CT findings such as extraluminal gas or contrast and discontinuity along the bowel wall. Indirect CT findings can help support the diagnosis, and include bowel wall thickening, pericolic fat stranding, abnormal bowel wall enhancement, abscess, and a feculent collection adjacent to the bowel. Common etiologies that cause large bowel perforation are colon cancer, foreign body aspiration, stercoral colitis, diverticulitis, ischemia, inflammatory and infectious colitides, and various iatrogenic causes. Recognizing a large bowel perforation on CT can be difficult at times, and there are various entities that may be misinterpreted as a colonic perforation. The purpose of this article is to outline the MDCT technique used for evaluation of suspected colorectal perforation, discuss relevant imaging findings, review common etiologies, and point out potential pitfalls in making the diagnosis of large bowel perforation.

Is abdominal CT useful for the management of patients with severe acute colitis complicating inflammatory bowel disease? A study in 54 consecutive patients

AIM

To evaluate the contribution of CT for the management of patients with severe acute exacerbation of colitis (SAC) complicating inflammatory bowel disease (IBD); in particular, its contribution to surgical decision making.

METHOD

All patients who were admitted to our institution for SAC complicating IBD were divided into two groups: group A (those who received surgical treatment); and group B (those who received medical treatment). Admission CT results were compared between groups.

RESULTS

From 2006 to 2015, 54 patients [26 male; median age 39 (17-71) years] presenting with SAC were placed in either group A (n = 41; 76%) or group B (n = 13; 24%). Surgical patients in group A more frequently had altered general status (50 vs 17%; P = 0.01). Physical examination, Lichtiger score, endoscopic findings and laboratory results were similar between the groups. There was no significant difference in CT data between the groups with respect to extent of the colitis (pan-colitis in 54 and 69%, respectively, P = 0.35), median colonic thickness [10 (4-16) vs 8 (6-11) mm, P = 0.15], target enhancement (88 vs 77%, P = 0.38) and occurrence of toxic megacolon (2 vs 0%).

CONCLUSION

Admission CT is not helpful in surgical decision making in SAC.

Computed tomography of bowel obstruction: tricks of the trade

Bowel obstruction (BO) is a frequent cause of hospitalization and surgical consultation for acute abdominal pain. It is usually suspected at physical examination, but clinical and laboratory data are often nonspecific. Thus, computed tomography plays a crucial role in a correct diagnosis of BO. Indeed, computed tomography can confirm a diagnosis of BO, and identify the location and cause of the obstruction. In this review, the computed tomography appearances of common and uncommon causes of BO and pseudo-obstruction are reviewed.

Large-Bowel Obstruction in the Adult: Classic Radiographic and CT Findings, Etiology, and Mimics

Large-bowel obstruction is an abdominal emergency with high morbidity and mortality rates if left untreated. Although abdominal radiography is usually the initial imaging study performed in patients suspected of having large-bowel obstruction, it may not be sufficient to distinguish obstruction from other causes of colonic dilatation. Computed tomography is the imaging method of choice as it can establish the diagnosis and cause of large-bowel obstruction. A contrast agent enema may be used to confirm or exclude large-bowel obstruction. In this review, the imaging findings in multiple causes of large-bowel obstruction are illustrated and compared with acute colonic pseudo-obstruction.

Radiographical evaluation of ulcerative colitis

Radiographical modalities have become important diagnostic tools in cases of ulcerative colitis (UC). Imaging can be used non-invasively to determine the extent of involvement, severity of disease and to detect disease-related complications and extra-intestinal inflammatory bowel disease (IBD) manifestations. While abdominal X-rays and barium enemas still retain their relevance in specific clinical settings, the use of computed tomography enterography (CTE) or magnetic resonance enterography (MRE) are now used as first-line investigations to exclude active small bowel disease in IBD patients and can be utilized to detect active colonic inflammation. Additionally, CT colonography and MR colonography are emerging techniques with potential applications in UC. Ultrasonography, leukocyte scintigraphy and positron emission tomography are novel abdominal imaging modalities currently being explored for IBD interrogations. This plethora of radiological imaging options has become a vital component of UC assessments.

Toxic megacolon complicating a first course of Crohn's disease: about two cases

Toxic megacolon is a rare and serious complication of Crohn’s disease. Because of the associated high morbidity and mortality, early recognition and management of toxic megacolon is important. Through two cases of toxic megacolon complicating Crohn’s disease, we assessed the clinical, radiologic and therapeutic characteristics of this complication.

A 35-year-old man presented a first course of Crohn’s disease treated with corticosteroid. He exhibited sudden severe abdominal pain and distension with shock. A plain abdominal radiography revealed toxic megacolon. He underwent medical therapy, but symptoms not relieved. The patient underwent subtotal colectomy with ileostomy. The resected specimen confirmed the diagnosis. Recovery of digestive continuity was performed. Endoscopic evaluation six months later did not shown recurrence. A 57-year-old man presented with severe acute colitis inaugurating Crohn’s disease, was treated with corticosteroid and antibiotics. He exhibited signs of general peritonitis. Computed tomographic examination revealed toxic megacolon with free perforation, showing prominent dilation of the transverse colon and linear pneumatosis. The patient underwent emergent subtotal colectomy and ileostomy. The final histological patterns were consisting with diagnosis of Crohn’s disease associated with cytomegalovirus infection. The patient underwent antiviral therapy during 15 days. Because of the high risk of postoperative recurrence, he underwent immunosuppressive therapy. Recovery of digestive continuity was performed successfully. Toxic megacolon in Crohn’s disease is a serious turning of this disease. We underscore the importance of early diagnosis of toxic megacolon and rapid surgical intervention if improvement is not observed on medical therapy.