Infectious ileocecitis caused by Yersinia, Campylobacter, and Salmonella: clinical, radiological and US findings

A population-based study of the appearances of enteric Campylobacter and non-typhoidal Salmonella infections on computed tomography

BACKGROUND

Swift identification and diagnosis of gastrointestinal infections are crucial for prompt treatment, prevention of complications, and reduction of the risk of hospital transmission. The radiological appearance on computed tomography could potentially provide important clues to the etiology of gastrointestinal infections. We aimed to describe features based on computed tomography of patients diagnosed with Campylobacter, Salmonella or Shigella infections in South Sweden.

METHODS

This was a retrospective observational population-based cohort study conducted between 2019 and 2022 in Skåne, southern Sweden, a region populated by 1.4 million people. Using data from the Department of Clinical Microbiology combined with data from the Department of Radiology, we identified all patients who underwent computed tomography of the abdomen CTA two days before and up to seven days after sampling due to the suspicion of Campylobacter, Salmonella or Shigella during the study period.

RESULTS

A total of 215 CTAs scans performed on 213 patients during the study period were included in the study. The median age of included patients was 45 years (range 11-86 years), and 54% (114/213) of the patients were women. Of the 215 CTAs, 80% (n = 172) had been performed due to Campylobacter and 20% (n = 43) due to Salmonella enteritis. CTA was not performed for any individual diagnosed with Shigella during the study period. There were no statistically significant differences in the radiological presentation of Campylobacter and Salmonella infections.

CONCLUSION

The most common location of Campylobacter and Salmonella infections was the cecum, followed by the ascending colon. Enteric wall edema, contrast loading of the affected mucosa, and enteric fat stranding are typical features of both infections. The CTA characteristics of Campylobacter and Salmonella are similar, and cannot be used to reliably differentiate between different infectious etiologies.

Differentiation of Yersinia enterocolitica enteritis from other bacterial enteritides by ultrasonography: A single-center case-control study

BACKGROUND

The diagnosis of Yersinia enterocolitica (Ye) enteritis is not easy because detection from stool culture is more difficult for Ye than for other bacterial enteritides. The establishment of characteristic ultrasonographic findings for Ye enteritis would help improve the detection rate of Ye enteritis along with performance of several cold cultures. This would facilitate appropriate selection of antibiotics based on antimicrobial susceptibility testing and contribute to a more accurate understanding of local public health. This study aimed to retrospectively compare ultrasonographic findings and clinical features between children with Ye enteritis and other bacterial enteritides.

METHODS

We identified patients treated for Ye enteritis (Ye group; n = 27) or other bacterial enteritides (Other enteritis group; n = 29) between 2014 and 2018. Ultrasonographic findings (including mean maximum diameter and mean major-minor axis ratio of ileocecal lymph nodes, wall thickness of the terminal ileum, and presence of a pericecal hyperechoic region), clinical symptoms, and laboratory findings at first visit were compared between groups.

RESULTS

No difference in mean maximum diameter of ileocecal lymph nodes was seen between groups. However, mean major-minor axis ratio of ileocecal lymph nodes was lower in the Ye group than in the Other enteritis group (p < 0.001). Presence of a pericecal hyperechoic region was more frequent in the Ye group than in the Other enteritis group (p < 0.001). The combined presence of a mean ileocecal lymph node major-minor axis ratio <1.51 and a pericecal hyperechoic region offered 100% sensitivity.

CONCLUSION

Characteristic ultrasonographic findings identified in this study may improve ultrasonographic differentiation of Y. enterocolitica enteritis from other bacterial enteritides.

Characteristics and Endoscopic Classification of Ulcerative Lesions Affecting the Ileocecal Valve

OBJECTIVES

The aim of this study was to propose an endoscopic classification system for ulcerative lesions on the ileocecal valve and investigate its relevance to the underlying etiology.

METHODS

Among the 60,325 patients who underwent colonoscopy at our hospital from January 2006 to December 2018, patients with ulcerative lesions on the ileocecal valve were included. The following data were obtained using the hospital's medical records: sex, age, clinical diagnosis, laboratory data, and endoscopic and histological findings. Patients who have ulcerative colitis and who were not evaluated by histological examination were excluded. Ulcerative lesions on the ileocecal valve were classified into 3 groups according to their endoscopic appearance: small shallow ulcerative lesions without edematous change (group A), lateral spreading shallow ulcerative lesions with edematous change (group B), and deep deformed ulcerative lesions (group C). The association between this endoscopic classification and its clinical diagnosis, clinical course, and the interobserver reliability were evaluated.

RESULTS

Of 72 patients who were eligible for analysis, 18 were assigned to group A, 9 to group B, and 45 to group C. Infectious enteritis was mainly assigned to group A (group A, 12; group B, none; and group C, 6; p < 0.0001), inflammatory bowel disease was mainly assigned to group C (group A, none; group B, 5; and group C, 35; p < 0.0001), and malignant tumor was assigned to group C only. Interobserver reliability was extremely high among the 3 examining doctors (kappa value 0.7-0.8).

CONCLUSION

Endoscopic classification was divided into 3 groups for ulcerative lesions on the ileocecal valve, and this system could be beneficial for presuming their clinical diagnoses.

Comparison of Clinical Characteristics According to the Existence of Secondary Appendicitis in Pediatric Acute Enterocolitis: A Single Center Study

PURPOSE

In patients with acute enterocolitis, radiologic findings are sometimes accompanied by secondary inflammation of the appendix. The purpose of this study was to evaluate the clinical features of acute enterocolitis with secondary inflammation of the appendix.

METHODS

Medical records from patients who underwent abdominal ultrasonography or computed tomography (CT) among those admitted for acute enterocolitis were retrospectively reviewed. Clinical features were compared by distinguishing patients with inflammation of the appendix from those without, based on their symptoms and laboratory findings.

RESULTS

Of the 165 patients, 12 (7.3%) had secondary inflammation of the appendix on ultrasonography and/or CT. Patients with secondary inflammation of the appendix were significantly older than those without (11.7 vs. 6.1 years, p=0.011) and more frequently had fever (83.3% vs. 49.0%, p=0.033), and high values of C-reactive protein (CRP) (5.38 vs. 0.32 mg/dL, p<0.001). The proportion of bacterial pathogens was higher in patients with secondary inflammation of the appendix (60% vs. 15.1%, p=0.004).

CONCLUSION

Patients with acute enterocolitis accompanied by secondary appendicitis more commonly have fever, higher CRP levels, higher bacterial pathogen detection rates, and longer hospital stays. Treatment equivalent to that of bacterial infection is required for patients with secondary appendicitis, and that their symptoms should be closely and continuously monitored and followed-up.

Ultrasonography in infectious and neoplastic diseases of the bowel and peritoneum

Ultrasonography is not the most cited imaging technique for the evaluation of infectious and neoplastic diseases of the gastrointestinal tract and the peritoneum, but it is often the initial technique used in the initial workup for nonspecific clinical syndromes. Despite its limitations, ultrasonography's strengths enable it to provide meaningful diagnostic information. To discuss the most important ultrasonographic, clinical, and epidemiological findings for infectious disease, we follow a topographical approach: stomach (Anisakis), proximal small bowel (Giardia lamblia, Strongyloides stercoralis, Mycobacterium avium-intracellulare complex, and Cryptosporidium), distal small bowel (Yersinia, Salmonella, and Campylobacter), terminal ileum and cecum (tuberculosis), right colon (Entamoeba histolytica), left colon (Shigella), sigmoid colon and rectum, pancolitis (Clostridium difficile, Cytomegalovirus, and Escherichia coli), and peritoneum. To discuss the ultrasonographic and clinical findings of the most common neoplastic diseases, we follow a nosological approach: polyploid lesions as precursors of tumors, carcinomas, neuroendocrine tumors, hematological tumors, mesenchymal tumors, and metastases. We briefly discuss tumors of the peritoneum and the use of ultrasonography to guide percutaneous biopsy procedures.

Sonographic assessment of infectious diseases of the gastrointestinal tract: from scanning to diagnosis

BACKGROUND

Sonography of the gastrointestinal (GI) tract is a practical, safe, inexpensive, and reproducible diagnostic tool for the evaluation, diagnosis, and follow-up of infectious bowel disease. The modality is rapidly gaining prominence among clinicians on a global scale. In the United States, however, ultrasound of the bowel remains underutilized primarily due to insufficient experience among radiologists and sonographers in performing sonographic bowel assessment. This lack of experience and knowledge results in misinterpretations, missed diagnoses, and underutilization of this modality in patients with acute abdomen, with the majority of GI pathology on sonography discovered incidentally.

OBJECTIVES

This article aims to demonstrate the characteristic sonographic findings associated with GI infectious processes as well as provide dedicated ultrasound protocols for evaluation of the GI tract.

CONCLUSION

This article serves a twofold purpose, raising awareness of the utility of this imaging modality within the radiology community and also providing practical teaching points for sonographic evaluation of infectious disorders of the GI tract.

Point-of-Care Ultrasound to Diagnose Colitis in the Emergency Department: A Case Series and Review of the Literature

BACKGROUND

Colitis refers to an inflammatory process of the colon, composed of a variety of different etiologies including inflammatory bowel disease, infectious colitis, ischemic colitis, and allergic colitis. Usually, abdominal computed tomography (CT) is the gold standard in diagnosing the various forms of colitis. However, by the use of point-of-care ultrasound (POCUS), one may occasionally be able to discern wall thickening, pericolic fluid, and adjacent hyperechoic mesenteric fat. One may also see abscesses, fistulae, or ascites.

CASE SERIES

This is a series of 6 patients who had findings consistent with colitis seen on POCUS performed by an emergency physician. These were confirmed by abdominal CT with contrast. Early detection by POCUS was able to lead to a rapid diagnosis and to expedite treatment. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The ability to detect findings of colitis by POCUS can be quickly learned by the emergency physician with a strong background in basic ultrasound. For many of the different subtypes of colitis, the initial treatment in the emergency department is the same: i.v. antibiotics, i.v. fluids, and "bowel rest" by maintaining the patient in nothing-by-mouth status. For the stable patient with high clinical suspicion of an infectious etiology of colitis, ultrasound can help confirm the diagnosis and rule out other etiologies. This may be especially important in certain populations such as children and young women, where one can avoid a significant amount of radiation being directed toward the pelvic area.

Studies on patients establish Crohn's disease as a manifestation of impaired innate immunity

The fruitless search for the cause of Crohn's disease has been conducted for more than a century. Various theories, including autoimmunity, mycobacterial infection and aberrant response to food and other ingested materials, have been abandoned for lack of robust proof. This review will provide the evidence, obtained from patients with this condition, that the common predisposition to Crohn's is a failure of the acute inflammatory response to tissue damage. This acute inflammation normally attracts large numbers of neutrophil leucocytes which engulf and clear bacteria and autologous debris from the inflamed site. The underlying predisposition in Crohn's disease is unmasked by damage to the bowel mucosa, predominantly through infection, which allows faecal bowel contents access to the vulnerable tissues within. Consequent upon failure of the clearance of these infectious and antigenic intestinal contents, it becomes contained, leading to a chronic granulomatous inflammation, producing cytokine release, local tissue damage and systemic symptoms. Multiple molecular pathologies extending across the whole spectrum of the acute inflammatory and innate immune response lead to the common predisposition in which defective monocyte and macrophage function plays a central role. Family linkage and exome sequencing together with GWAS have identified some of the molecules involved, including receptors, molecules involved in vesicle trafficking, and effector cells. Current therapy is immunosuppressant, which controls the symptoms but accentuates the underlying problem, which can only logically be tackled by correcting the primary lesion/s by gene therapy or genome editing, or through the development of drugs that stimulate innate immunity.

Ileocecal thickening: Clinical approach to a common problem

Ileocecal thickening (ICT) is a common finding on radiological imaging. It can be caused by a variety of inflammatory, infectious, or neoplastic conditions, and evaluating a patient of ICT can be a challenging task. Intestinal tuberculosis (ITB), Crohn's disease (CD), and adenocarcinoma are the most common causes. Enteric bacterial infections, cytomegalovirus, histoplasmosis, amebiasis, systemic vasculitis, lymphoma, etc. should be suspected in appropriate clinical settings. However, it could often be a spurious or nonspecific finding. A thickness of more than 3 mm in a normally distended small bowel is usually considered abnormal. Detailed evaluation of imaging of the site and extent of thickening; the degree and pattern of thickening; and the associated findings, such as degree of fat stranding, fibrofatty proliferation, adjacent lymph nodes, and solid organ involvement, should be performed. Ileocolonoscopy is an important tool for diagnosing and obtaining samples for tissue diagnosis. Histopathology is usually the gold standard for diagnosis, although—not uncommonly—findings could be nonspecific, and reaching a definitive diagnosis is difficult. As such, a systematic approach with the integration of clinical, biochemical, radiological, endoscopic, histological, and other laboratory tests is the key to reaching a diagnosis. In this article, we review the causes of ICT and present a clinical approach for the management of ICT.

Acute Terminal Ileitis in Children: A Retrospective Study in a Pediatric Emergency Department

OBJECTIVES

This study aims to describe the clinical presentation and outcome of patients diagnosed with acute ileitis in our pediatric emergency department.

METHODS

We performed a retrospective study of all patients diagnosed with terminal ileitis by abdominal ultrasonography findings in our pediatric emergency department, over the years 2013 and 2014. Patients with previous diagnosis of inflammatory bowel disease (IBD) were excluded. Data collected were clinical, radiological, and laboratory data at diagnosis; outcome including hospitalization care; and outpatient follow-up in pediatric gastroenterology and/or primary care.

RESULTS

A total of 20 cases were retrieved and studied. All of them presented with abdominal pain, 65% located in the right lower quadrant. Leukocyte count, C-reactive protein, and fibrinogen levels (means, 12,889; 4/μL; 50.1 mg/L; and 575 mg/dL, respectively) were above normal range. Hemoglobin and platelet count were normal. A microbial cause of ileitis was found in 3 cases (Yersinia enterocolitica, Campylobacter jejuni, and Adenovirus). Nine patients were referred to a pediatric gastroenterology unit. No cases of IBD were found.

CONCLUSIONS

Acute ileitis is a rare and benign cause of abdominal pain in the pediatric emergency department. The main intervention on initial assessment is to rule out potentially severe causes of abdominal pain that could benefit of an emergency surgical procedure. In contrast with adults and adolescents, acute ileitis in children does not have a clear association with development of IBD.

Ilececum: A Comprehensive Review

For gastrointestinal endoscopists, the ileocecum is the finishing line during colonoscopy and it is identified by three endoscopic landmarks: terminal ileum, ileocecal valve, and the appendiceal orifice. Although ileal intubation is recommended during routine screening colonoscopy, it is not required in most cases of screening colonoscopy. Ileal intubation is indicated in certain circumstances such as suspected inflammatory bowel disease and GI bleeding. There is much pathology that can be observed within the ileocecum. Careful and systematic examination should be stressed during GI endoscopic training and practice. In this review, the authors demonstrate its anatomy, endoscopic findings, and pathologies.

The role of neutrophils in the pathogenesis of Crohn's disease

Crohn's disease (CD) is caused by a trigger, almost certainly enteric infection by one of a multitude of organisms that allows faeces access to the tissues, at which stage the response of individuals predisposed to CD is abnormal. In CD the failure of acute inflammation results in the failure to recruit neutrophils to the inflammatory site, as a consequence of which the clearance of bacteria from the tissues is defective. The retained faecal products result in the characteristic chronic granulomatous inflammation and adaptive immune response. Impaired of digestion of bacteria and fungi by CGD neutrophils can result in a similar pathological and clinical picture. The neutrophils in CD are normal and their inadequate accumulation at sites of inflammation generally results from diminished secretion of proinflammatory cytokines by macrophages consequent upon disordered vesicle trafficking.

Campylobacter Infections in Children

EDUCATION GAP

Campylobacter is one of the 2 most common causes of foodborne illness in the United States. It most commonly occurs in children younger than 5 years of age. Campylobacter species can cause a wide range of syndromes, from asymptomatic infections to severe systemic infections.

OBJECTIVES

After completing this article, readers should be able to: 1. Recognize that Campylobacter is a common cause of foodborne illness in the United States and internationally. 2. Understand the indications for testing and the treatment of Campylobacter infection.

Clinical Characteristics and Ultrasonographic Findings of Acute Bacterial Enterocolitis in Children

PURPOSE

This study clarified the bacterial pathogens currently causing acute infectious enterocolitis (AIE) in children and evaluated the clinical characteristics and ultrasonographic findings according to the different pathogens.

METHODS

Medical records regarding age, sex, clinical symptoms, laboratory data, identified enteropathogens, ultrasonographic findings, treatment, and outcome of 34 patients who were diagnosed with AIE via stool examination using multiplex polymerase chain reaction (PCR) or culture, were retrospectively reviewed.

RESULTS

Twenty-four patients (70.6%) were male. The mean age of the patients was 8.5±6.2 (range, 1.1-17.1) years. Six bacterial pathogens were isolated: Salmonella species (spp.) (32.4%), Campylobacter spp. (20.6%), verotoxin-producing Escherichia coli (14.7%), Staphylococcus aureus (11.8%), Clostridium difficile (8.8%), and Shigella spp. (2.9%). Abdominal pain occurred in all patients regardless of pathogen. The patients infected with Salmonella were older than those infected with verotoxin-producing E. coli (p<0.05). C-reactive protein levels were higher in patients with Salmonella and Campylobacter infections than in those with verotoxin-producing E. coli infection (p<0.05), the other clinical and laboratory data were indistinguishable between pathogens. Ultrasonography demonstrated diverse involvement of bowel segments according to pathogen. Wall thickening of both the ileum and the entire colon was the most common lesion site regardless of pathogen.

CONCLUSION

Various bacterial agents cause AIE and the symptoms are diverse symptoms, however, all most children recovered spontaneously. Use of multiplex PCR on stool samples warrants improvement of its sensitivity for diagnosis of enteropathogenic bacteria. Ultrasonographic examination is useful for diagnosis of AIE; it can also detect the disease extent and severity.

Making sense of the cause of Crohn's - a new look at an old disease

The cause of Crohn’s disease (CD) has posed a conundrum for at least a century. A large body of work coupled with recent technological advances in genome research have at last started to provide some of the answers. Initially this review seeks to explain and to differentiate between bowel inflammation in the primary immunodeficiencies that generally lead to very early onset diffuse bowel inflammation in humans and in animal models, and the real syndrome of CD. In the latter, a trigger, almost certainly enteric infection by one of a multitude of organisms, allows the faeces access to the tissues, at which stage the response of individuals predisposed to CD is abnormal. Direct investigation of patients’ inflammatory response together with genome-wide association studies (GWAS) and DNA sequencing indicate that in CD the failure of acute inflammation and the clearance of bacteria from the tissues, and from within cells, is defective. The retained faecal products result in the characteristic chronic granulomatous inflammation and adaptive immune response. In this review I will examine the contemporary evidence that has led to this understanding, and look for explanations for the recent dramatic increase in the incidence of this disease.

Making sense of the cause of Crohn's - a new look at an old disease

The cause of Crohn's disease (CD) has posed a conundrum for at least a century. A large body of work coupled with recent technological advances in genome research have at last started to provide some of the answers. Initially this review seeks to explain and to differentiate between bowel inflammation in the primary immunodeficiencies that generally lead to very early onset diffuse bowel inflammation in humans and in animal models, and the real syndrome of CD. In the latter, a trigger, almost certainly enteric infection by one of a multitude of organisms, allows the faeces access to the tissues, at which stage the response of individuals predisposed to CD is abnormal. Direct investigation of patients' inflammatory response together with genome-wide association studies (GWAS) and DNA sequencing indicate that in CD the failure of acute inflammation and the clearance of bacteria from the tissues, and from within cells, is defective. The retained faecal products result in the characteristic chronic granulomatous inflammation and adaptive immune response. In this review I will examine the contemporary evidence that has led to this understanding, and look for explanations for the recent dramatic increase in the incidence of this disease.

Point-of-Care Ultrasonography for Appendicitis Uncovers Two Alternate Diagnoses

We present two cases of pediatric patients initially presenting with a clinical suspicion of acute appendicitis. In these cases, point-of-care ultrasonography was performed early in the patient's emergency department course, leading to alternate diagnoses. This article highlights a role for point-of-care ultrasound in the diagnoses of two alternate conditions that clinically mimic appendicitis: Meckel diverticulitis and acute ileocecitis. We offer a brief overview of terminology, relevant literature, and ultrasound scanning technique for the right-lower-quadrant point-of-care ultrasound evaluation.

Current Role of Ultrasound in Small Bowel Imaging

Bowel ultrasound is cheap, relatively quick, allows dynamic evaluation of the bowel, has no radiation burden, is well tolerated by patients, and allows repeat imaging. Bowel ultrasound requires a systematic assessment of the entire bowel using high-frequency probes. In addition, hydrosonography and contrast-enhanced ultrasound may be performed. We present the normal sonographic appearances of large and small bowel and the sonographic appearances of acute appendicitis, Crohn's disease, celiac disease, intussusception, infectious enteritis, intestinal tuberculosis, small bowel ileus and obstruction, small bowel ischemia, and malignant tumors.

Reprogramming of Yersinia from virulent to persistent mode revealed by complex in vivo RNA-seq analysis

We recently found that Yersinia pseudotuberculosis can be used as a model of persistent bacterial infections. We performed in vivo RNA-seq of bacteria in small cecal tissue biopsies at early and persistent stages of infection to determine strategies associated with persistence. Comprehensive analysis of mixed RNA populations from infected tissues revealed that Y. pseudotuberculosis undergoes transcriptional reprogramming with drastic down-regulation of T3SS virulence genes during persistence when the pathogen resides within the cecum. At the persistent stage, the expression pattern in many respects resembles the pattern seen in vitro at 26oC, with for example, up-regulation of flagellar genes and invA. These findings are expected to have impact on future rationales to identify suitable bacterial targets for new antibiotics. Other genes that are up-regulated during persistence are genes involved in anaerobiosis, chemotaxis, and protection against oxidative and acidic stress, which indicates the influence of different environmental cues. We found that the Crp/CsrA/RovA regulatory cascades influence the pattern of bacterial gene expression during persistence. Furthermore, arcA, fnr, frdA, and wrbA play critical roles in persistence. Our findings suggest a model for the life cycle of this enteropathogen with reprogramming from a virulent to an adapted phenotype capable of persisting and spreading by fecal shedding.

To establish infection and colonize within a host, infecting pathogens have to cope with a variety of destructive surroundings. The food-borne pathogen Y. pseudotuberculosis can cause persistent infection in mice. Upon infection, Y. pseudotuberculosis passes the anti-microbial gastrointestinal milieu and finally remains associated with lymphoid follicles in cecal tissue surrounded by polymorphonuclear leukocytes, indicating that the bacteria are exposed to multiple environmental cues. We performed complex RNA-seq of small cecal biopsies of infected mice to reveal Y. pseudotuberculosis gene expression in vivo. We found that Y. pseudotuberculosis underwent reprogramming from a virulent phenotype, expressing virulence genes during early infection, to an adapted phenotype capable of persisting in the harsh cecal environment. Persistence was characterized by a novel expression pattern with down-regulation of virulence genes and up-regulation of genes involved in anaerobiosis, chemotaxis, and protection against oxidative and acidic stress. Mutagenesis of selected genes revealed that the regulator rovA was critical for the establishment of infection, and that arcA, fnr, frdA, and wrbA play critical roles in maintaining infection for long periods of time. Our study shows the power of RNA deep sequencing, which can be used to reveal the in vivo expression patterns of small amounts of bacteria in complex intestinal environments.

Colonization of cecum is important for development of persistent infection by Yersinia pseudotuberculosis

Yersiniosis is a human disease caused by the bacterium Yersinia pseudotuberculosis or Yersinia enterocolitica. The infection is usually resolved but can lead to postinfectious sequelae, including reactive arthritis and erythema nodosum. The commonly used Yersinia mouse infection model mimics acute infection in humans to some extent but leads to systemic infection and eventual death. Here, we analyzed sublethal infection doses of Y. pseudotuberculosis in mice in real time using bioluminescent imaging and found that infections using these lower doses result in extended periods of asymptomatic infections in a fraction of mice. In a search for the site for bacterial persistence, we found that the cecum was the primary colonization site and was the site where the organism resided during a 115-day infection period. Persistent infection was accompanied by sustained fecal shedding of cultivable bacteria. Cecal patches were identified as the primary site for cecal colonization during persistence. Y. pseudotuberculosis bacteria were present in inflammatory lesions, in localized foci, or as single cells and also in neutrophil exudates in the cecal lumen. The chronically colonized cecum may serve as a reservoir for dissemination of infection to extraintestinal sites, and a chronic inflammatory state may trigger the onset of postinfectious sequelae. This novel mouse model for bacterial persistence in cecum has potential as an investigative tool to unveil a deeper understanding of bacterial adaptation and host immune defense mechanisms during persistent infection.

Shewanella putrefaciens bacteraemia associated with terminal ileitis

Shewanella putrefaciens has a wide geographical distribution, including sea- and fresh water, fish and soil, but it is an unusual pathogen in humans. A previously healthy boy without known immunodeficiency presented with fever, abdominal pain and diarrhoea, and a mass in the right lower quadrant. Terminal ileitis was confirmed by MRI and Shewanella putrefaciens was isolated from two separate blood cultures. This is the first report of terminal ileitis associated with Shewanella putrefaciens septicaemia.

Diagnosis of bowel diseases: The role of imaging and ultrasonography

Examinations with a visualisation of the anatomy and pathology of the gastrointestinal (GI) tract are often necessary for the diagnosis of GI diseases. Traditional radiology played a crucial role for many years. Endoscopy, despite some limitations, remains the main technique in the differential diagnosis and treatment of GI diseases. In the last decades, the introduction of, and advances in, non-invasive cross-sectional imaging modalities, including ultrasound (US), computed tomography (CT), positron-emission tomography (PET), and magnetic resonance imaging, as well as improvements in the resolution of imaging data, the acquisition of 3D images, and the introduction of contrast-enhancement, have modified the approach to the examination of the GI tract. Moreover, additional co-registration techniques, such as PET-CT and PET-MRI, allow multimodal data acquisition with better sensitivity and specificity in the study of tissue pathology. US has had a growing role in the development and application of the techniques for diagnosis and management of GI diseases because it is inexpensive, non-invasive, and more comfortable for the patient, and it has sufficient diagnostic accuracy to provide the clinician with image data of high temporal and spatial resolution. Moreover, Doppler and contrast-enhanced ultrasound (CEUS) add important information about blood flow. This article provides a general review of the current literature regarding imaging modalities used for the evaluation of bowel diseases, highlighting the role of US and recent developments in CEUS.

Emergent pediatric US: what every radiologist should know

Appendicitis, intussusception, and hypertrophic pyloric stenosis (HPS) are three of the most common reasons for emergent abdominal imaging in pediatric patients. Although the use of computed tomography has risen dramatically over the past 2 decades, children are particularly at risk for the adverse effects of ionizing radiation, and even low-dose radiation is associated with a small but significant increase in lifetime risk of fatal cancer. In most emergency departments, the use of magnetic resonance (MR) imaging as a primary modality for the evaluation of a child with abdominal pain remains impractical due to its high cost, its limited availability, and the frequent need for sedation. Ultrasonography (US) does not involve ionizing radiation and, unlike MR imaging, is relatively inexpensive, is widely available, and does not require sedation. Another major advantage of US in abdominal imaging is that it allows dynamic assessment of bowel peristalsis and compressibility. Delayed diagnosis of any of the aforementioned disease processes can lead to serious morbidity and, in some cases, death. The ability to diagnose or exclude disease with US should be part of a core radiology skill set for any practice that includes a pediatric population.

Anti-Yersinia antibodies are not associated with microscopic colitis in an American case-control study

BACKGROUND

Microscopic colitis (MC), which consists of lymphocytic colitis and collagenous colitis, may be triggered by gastrointestinal infections. Studies have suggested a relationship between MC and Yersinia enterocolitica infection. We tested this hypothesis in a case-control study of American patients with MC.

METHODS

Serum was collected from 47 patients with MC and 44 age- and gender-matched healthy controls at a large referral center in the mid-western United States. Anti-IgA and IgG antibodies to Y. enterocolitica were measured using an enzyme-linked immunosorbent assay (ELISA). Fisher's exact test was used to assess statistical significance.

RESULTS

There were no differences between the two groups for seroprevalence of anti-Yersinia IgA (cases 2.1%, controls 2.3%, p = 1.00) or IgG antibodies (cases 4.3%, controls 6.8%, p = 0.67). There was no correlation between antibody titers and duration of MC diagnosis.

CONCLUSION

Our data do not support the role of exposure to Y. enterocolitica in an American group of patients with MC.

Imaging of acute right lower quadrant abdominal pain: differential diagnoses beyond appendicitis

Evaluation of acute right lower quadrant pain remains a common and challenging clinical scenario for emergency medicine physicians due to frequent nonspecific signs, symptoms, and physical examination findings. Therefore, imaging has evolved to play a pivotal role in the emergency setting. While appendicitis is a common cause for acute pain, there are numerous other important differential considerations with which the radiologist must be aware. The purpose of this review is to list an anatomy-based, encompassing differential diagnosis in addition to acute appendicitis for right lower quadrant pain; demonstrate the key imaging findings of numerous differential considerations; and describe helpful imaging and clinical features useful in narrowing the differential diagnosis.

Beyond appendicitis: common and uncommon gastrointestinal causes of right lower quadrant abdominal pain at multidetector CT

Right lower quadrant abdominal pain is one of the most common causes of a patient visit to the emergency department. Although appendicitis is the most common condition requiring surgery in patients with abdominal pain, right lower quadrant pain can be indicative of a vast list of differential diagnoses and is thus a challenge for clinicians. Other causes of right lower quadrant pain beyond appendicitis include inflammatory and infectious conditions involving the ileocecal region; diverticulitis; malignancies; conditions affecting the epiploic appendages, omentum, and mesentery; and miscellaneous conditions. Multidetector computed tomography (CT) has emerged as the modality of choice for evaluation of patients with several acute traumatic and nontraumatic conditions causing right lower quadrant pain. Multidetector CT is an extremely useful noninvasive method for diagnosis and management of not only the most common causes such as appendicitis but also less common conditions.

Ileitis: when it is not Crohn's disease

Ileitis, or inflammation of the ileum, is often caused by Crohn's disease. However, ileitis may be caused by a wide variety of other diseases. These include infectious diseases, spondyloarthropathies, vasculitides, ischemia, neoplasms, medication-induced, eosinophilic enteritis, and others. The clinical presentation of ileitis may vary from an acute and self-limited form of right lower quadrant pain and/or diarrhea, as in the majority of cases of bacterial ileitis, but some conditions (ie, vasculitis or Mycobacterium tuberculosis) follow a chronic and debilitating course complicated by obstructive symptoms, hemorrhage, and/or extraintestinal manifestations. Ileitis associated with spondylarthropathy or nonsteroidal anti-inflammatory drugs is typically subclinical and often escapes detection unless further testing is warranted by symptoms. In a minority of patients with long-standing Crohn's ileitis, the recrudescence of symptoms may represent a neoplasm involving the ileum. Distinguishing between the various forms of ileitis remains a test of clinical acumen. The diagnosis of the specific etiology is suggested by a detailed history and physical examination, laboratory testing, and ileocolonoscopy and/or radiologic data.

Optimized protocol for diagnosis of acute ileitis

BACKGROUND & AIMS

Suspected acute ileitis (AI) is a poorly defined clinical condition with multiple causes; its diagnostic protocol has not been standardized properly. We performed a prospective evaluation of the incidence and causes of AI to create a standard protocol for diagnosis.

METHODS

The definition of AI included abdominal pain, diarrhea, fever, and at least 1 confirmatory imaging method (abdominal computed tomography scan or ultrasound) showing pathologic changes in the terminal ileum that indicated ileal inflammation. We studied all patients with a presumptive diagnosis of AI seen in the Emergency Room at the Ramón y Cajal Hospital in Madrid, from March 2005 to May 2007, according to a pre-established protocol. Sixty-six patients with primary AI were followed up for at least 6 months.

RESULTS

An infectious cause was found in 33.3% of cases; the most frequently detected microorganism was Yersinia spp. A gynecologic condition was identified in 9.1% of cases initially diagnosed as AI, representing 13.95% of the cases among female patients. Crohn's disease was identified in 12.1% of patients. The diagnostic protocol led to negative results in 33.4% of the patients; 6.1% of patients did not complete the study. The initial diagnosis did not change among any of the patients during the follow-up period.

CONCLUSIONS

This protocol led to a definitive diagnosis of AI in more than 60% of potential cases. The most common cause was acute infection. About 10% of cases were of gynecologic origin and about 12% of patients presented with Crohn's disease.

Acute bloody diarrhea: a medical emergency for patients of all ages

Acute bloody diarrhea should be considered a medical emergency. Its causes are frequently serious or actionable or both and are usually identified. However, acute bloody diarrhea as a stand-alone clinical presentation has received little scholarly attention in the past several decades. Although the range of possible causes of acute bloody diarrhea is broad, infectious considerations are paramount and should always be prioritized in the evaluation of such patients. History, examination, and laboratory testing should be focused on minimizing time to diagnosis (and, by extension, to implementing appropriate therapy). Strategically chosen tests and imaging, avoidance of extraneous diagnostic pursuits, and provision of supportive care while awaiting diagnostic clarity are central to the adroit management of patients with acute bloody diarrhea. Diagnostic considerations differ somewhat between adults and children but have many elements in common, including the need for vigilance in detecting Escherichia coli O157:H7 infection. In this review, we discuss diagnostic approaches (emphasizing the importance of rapid, accurate, and thorough microbiologic investigation) and measures that can be taken to support patients while awaiting information that determines the cause of their disease. These topics are discussed in the context of the medical care that is available to children and adults with bloody diarrhea in most institutions in developed nations.

Transabdominal sonography in assessment of the bowel in adults

OBJECTIVE

We describe the key sonographic features and technical aspects of assessment of bowel disorders in adults.

CONCLUSION

Initial imaging with transabdominal sonography in the radiologic evaluation of bowel disease in adults often is reserved for patients with equivocal historical, physical, and laboratory findings related to the gastrointestinal tract. Because of technologic advances and accumulated experience in interpretation of the images, sonography yields substantial information about gastrointestinal disorders.

Colonic diseases: the value of US examination

The colon is affected by a number of diseases, mainly inflammatory, ischemic, and neoplastic conditions. Depending upon clinical indications endoscopy, US, CT, or other radiological methods are used for evaluation. The fact that US is frequently used as the initial imaging method in patients with non-specific clinical symptoms allows for greater influence in further diagnostic evaluation and with treatment, provided the investigator is familiar with the features of different intestinal diseases. This article will describe the anatomical characteristics of the colon, the US technique for examination of the colon, and the typical US features of the more common diagnoses of the colon.

Mimics of Appendicitis: Alternative Nonsurgical Diagnoses with Sonography and CT

OBJECTIVE

Our objective was to illustrate the imaging features of alternative nonsurgical disorders in patients presenting with clinical signs of appendicitis.

CONCLUSION

This article illustrates the sonographic and CT features of various appendicitis-mimicking conditions that are self-limiting or that can be treated conservatively. A correct imaging diagnosis of these disorders may prevent a nontherapeutic appendectomy and unnecessary hospitalization.

High-resolution ultrasonography in gastrointestinal graft-versus-host disease

Gastrointestinal graft-versus-host disease (GVHD) is one of the main causes of therapy-related death after allogeneic hemopoietic stem cell transplantation. Early diagnosis and immediate treatment are probably essential for improving clinical outcome. High-resolution sonography allows the evaluation of single bowel wall layers throughout the small and large bowel. We report the sonographic findings of seven consecutive patients with histologically confirmed GVHD grade II-IV of the gastrointestinal tract. The patients were examined sonographically within the 1st week after onset of clinical symptoms. Dilatation of the colon and striking bowel wall thickening were early and common features in these patients. Sonography may become a useful tool for diagnosis of patients with gastrointestinal GVHD. Its role for preclinical diagnosis, grading of severity of disease, and guiding therapy of patients with gastrointestinal GVHD warrants evaluation in prospective studies.

Sonographic diagnosis of colitis in children

To assist the radiologist in differentiating the colitis in children, this review proposes a systematic US approach to the disease, presents the US aspect of the normal colon and describes three distinctive US patterns reflecting the intramural extension of the histopathological changes. Each pattern corresponds to one or several diseases producing alterations in the same layer(s). Stratified thickening suggests an inflammatory mucosal process resulting from infection (as in advanced appendicitis or in infectious colitis) or to inflammation (as in IBD). Nonstratified thickening with loss of the haustral folds reflects a marked submucosal infiltrate. Color Doppler is required to distinguish between an inflammatory disease (as advanced CD or neutropenic colitis) and an ischemic colitis (HUS in children). Nonstratified thickening with preservation of the length of the haustral folds is the sign of an intraluminal deposit due to PMC. Correlating the sonographic pattern and the anatomic distribution of the disease with the clinical and laboratory findings often permits to propose a specific diagnosis.

Detection of ileocecal Crohn's disease using ultrasound as the primary imaging modality

At our hospital ultrasound (US) is used as an initial screening procedure in all patients with abdominal symptoms. The purpose of this study was to assess the effect of this policy on the detection of ileocecal Crohn's disease. We retrospectively studied all patients with a new diagnosis of ileocecal Crohn's disease from our institute over the period 1990-2001. The final diagnosis was based on clinical follow-up and pathological, surgical, US, and other radiological findings. We noted who referred the patient to the radiology department, what the initial clinical presumption was, and what the first imaging study was. US diagnoses were determined from the initial US report and US findings were registered from the images. There were a total of 47 patients (20 men, 27 women) with a mean age of 30 years and a median age of 27 years (range 14-75 years). In all patients the initial imaging study was an abdominal US. Using US, a confident diagnosis of ileocecal Crohn's disease was made in 35 of the 47 patients, Crohn's disease was suggested among the differential diagnosis in 10, and an incorrect diagnosis was made in 2 patients. In 28 of 47 patients, the referring physician did not consider Crohn's disease when requesting the initial US examination. In eight patients with appendicitis-like symptoms, the US findings strongly influenced the decision to refrain from operation at that point in time. US, when used as a low-threshold diagnostic procedure, is a reliable and noninvasive means for making an early diagnosis of ileocecal Crohn's disease in patients who present with atypical symptoms. It may prevent both unnecessary therapeutic delay as well as unnecessary surgery.

Ultrasonography of the acute abdomen

Although multislice, helical CT is increasingly replacing ultrasonography for the evaluation of patients with acute abdominal pain, ultrasound does have certain specific advantages over CT. This article discusses the advantages of ultrasound in imaging of the acute abdomen, exploring such areas as appendicitis, ileocecal Crohn's disease, infectious ileocolitis and infectious ileocecitis, mesenteric lymphadenitis, cecal carcinoma, sigmoid diverticulitis, right-sided colonic diverticulitis, and perforated peptic ulcer.

Acute appendicitis mimicking infectious enteritis: diagnostic value of sonography

OBJECTIVE

To verify the role of sonography in screening of acute appendicitis in patients admitted to an infectious disease unit for suspected acute infectious enteritis.

METHODS

One hundred eighty consecutive patients (102 male and 78 female; age range, 5-72 years; mean age, 31 years) admitted for suspected infectious enteritis or typhoid fever were prospectively studied with abdominal sonography within 48 hours after admission. None of the patients had peritoneal irritation. Forty-six patients (25%) had white blood cell counts of more than 10,000/mm3 (range, 10,300-18,000/mm3). The diagnosis of acute appendicitis was made when a detectable appendix with an anteroposterior diameter of greater than 7 mm could be seen on sonography.

RESULTS

Eleven (6%) of 180 patients had thickened appendixes (anteroposterior diameter range, 7-14 mm); 2 of them had periappendiceal abscesses. Four (36%) of 11 patients with acute appendicitis had high white blood cell counts. All sonographic diagnoses of acute appendicitis and periappendiceal abscesses were confirmed at surgery. Sonography ruled out acute appendicitis in 169 patients. In all of them, clinical and sonographic follow-up excluded the diagnosis of acute appendicitis. Normal appendixes were shown on sonography in 38 (22%) of 169 cases and were not detectable in 131 (78%) of 169.

CONCLUSIONS

Sonography of the appendix is a useful method for early assessment of acute appendicitis in patients thought to have enteritis or typhoid fever.