Imaging features of enterohemorrhagic Escherichia coli colitis

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.

Shiga Toxin-Associated Hemolytic Uremic Syndrome: A Narrative Review

The severity of human infection by one of the many Shiga toxin-producing Escherichia coli (STEC) is determined by a number of factors: the bacterial genome, the capacity of human societies to prevent foodborne epidemics, the medical condition of infected patients (in particular their hydration status, often compromised by severe diarrhea), and by our capacity to devise new therapeutic approaches, most specifically to combat the bacterial virulence factors, as opposed to our current strategies that essentially aim to palliate organ deficiencies. The last major outbreak in 2011 in Germany, which killed more than 50 people in Europe, was evidence that an effective treatment was still lacking. Herein, we review the current knowledge of STEC virulence, how societies organize the prevention of human disease, and how physicians treat (and, hopefully, will treat) its potentially fatal complications. In particular, we focus on STEC-induced hemolytic and uremic syndrome (HUS), where the intrusion of toxins inside endothelial cells results in massive cell death, activation of the coagulation within capillaries, and eventually organ failure.

Computed Tomographic Findings of Enterohemorrhagic Escherichia coli O157 Infection: An Analysis of a 7-Case Regional Outbreak

PURPOSE

We experienced an outbreak of enterohemorrhagic Escherichia coli (EHEC) colitis. The purpose of this study was to reveal the computed tomographic (CT) findings on EHEC colitis.

METHODS

The subjects were 7 patients with EHEC colitis, which was caused by eating a contaminated Japanese rice cake. Contrast CT was performed on all patients. Two radiologists evaluated the CT findings (the thickness of colon wall, the range of thickened colon, and the existence of dirty fat signs around the colon, ascites, and swelling of lymph nodes), in accordance with our PACS system.

RESULTS

Wall swelling of the proximal colon from cecum to ascending colon was noted in all patients. Small intestine lesions were not noted in any cases.

CONCLUSIONS

We should consider EHEC infection as part of a differential diagnosis when the findings of severe right colitis are seen without enteritis.

Bacterial colitis

Bacterial colitis results in an inflammatory-type diarrhea that is characterized by bloody, purulent, and mucoid stool. These diseases have been designated as bacterial hemorrhagic enterocolitis. Associated symptoms include fever, tenesmus, and severe abdominal pain. The pathologic changes range from superficial exudative enterocolitis to a transmural enterocolitis with ulceration. Common pathologic bacteria causing bacterial colitis include Campylobacter, Salmonella, Shigella, Escherichia, and Yersinia species. The primary source of transmission is fecal-oral spread and ingestion of contaminated food and water. Although detailed history and identification of specific risk factors assist in the diagnosis, definitive diagnosis requires bacterial identification. Therefore, the physician must be familiar with the disease pathophysiology, epidemiology, and specific diagnostic modalities for clinical diagnosis and management. Specific tests are used to detect enteric pathogens and include stool and rectal swab culture, histology, and identification of specific bacterial toxins. Although many of these bacterial colitis infections are self-limiting, antibiotics should be used for high-risk patients and patients with complicated 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.

Escherichia coli 0157 enterohaemorrhagic colitis associated with pyelonephritis: CT findings

Escherichia coli 0157:H7 is increasingly being recognized as a cause of infectious colitis, which typically results in bloody diarrhoea in an afebrile patient. The absence of fever often means that an infectious process is not considered in the differential diagnosis, particularly as this organism will not be detected in routine stool cultures. Inappropriate antibiotic therapy may increase the risk of development of haemolytic uraemic syndrome, a potentially fatal complication of this form of colitis, hence the importance of accurate diagnosis. On CT, it is characterized by severe diffuse colonic wall thickening, with little or no pericolic inflammatory changes. The radiologist may be the first to suspect the correct diagnosis and so should be aware of its imaging appearances. We report the case of a 19-year-old man who presented with typical radiological findings of enterohaemorrhagic colitis and whose CT also showed evidence of acute pyelonephritis; we suggest that this combination of abnormalities should further heighten radiologists' suspicions of infection due to E. coli 0157:H7, despite the absence of fever.

Enteric infections and diagnostic testing

PURPOSE OF REVIEW

Gastrointestinal pathogens profoundly affect human health and well being. The provider's ability to render optimal care often highly depends on diagnostic microbiologic support. We aim to provide a clinically pertinent assessment of the current state of our ability to diagnose human gastrointestinal pathogens and describe (and decry) the unsophistication of many current diagnostic methods and strategies.

RECENT FINDINGS

Recent advances involve improved stool polymerase chain reaction assays and application of this technology to a broader panel of pathogens, stool antigen assays, and improved culture techniques, but there is little penetration of such diagnostic advances into clinical practice. Many such techniques remain limited to research or epidemiologic use and are not typically available in the clinical laboratory.

SUMMARY

Multiple clinical and laboratory factors need to be considered when attempting to diagnose the wide variety of gastrointestinal pathogens afflicting humans. Careful interpretation of diagnostic tests with attention to the population studied and the characteristics of each test is necessary.

Abnormal computed tomography findings among children with viral gastroenteritis and symptoms mimicking acute appendicitis

OBJECTIVE

To evaluate computed tomography (CT) findings in pediatric patients with viral gastroenteritis who presented with clinical features of acute abdomen.

PATIENTS AND METHODS

During 2 seasons of viral gastroenteritis from 2005 to 2007, 302 children with acute gastrointestinal symptoms were admitted to our center for treatment of dehydration and associated complications. Stool specimens obtained from 130 of the 302 were tested for norovirus with the reverse transcriptase-polymerase chain reaction method.

RESULTS

Among the 130 patients, 44 tested positive for norovirus, 34 for rotavirus, and 1 for adenovirus. In the remaining 51, except one with Campylobacter jejuni, no viral or bacterial pathogen was detectable. An abdominal CT scan was performed in 4 patients with norovirus and in 1 with rotavirus for suspected acute abdomen including acute appendicitis. Computed tomography (CT) findings were similar among the 5 patients, including thickening of the bowel wall and fluid-filled bowel loops in the small intestine with no pathological findings in the stomach, appendix, or colon.

CONCLUSIONS

Anatomical changes in the small intestine were shown by CT in 5 children with viral gastroenteritis who presented with acute abdomen. These imaging features of viral gastroenteritis may be useful in differential diagnosis of acute abdomen to avoid unnecessary surgery.

Foodborne illness

While few patients with foodborne illness present with life-threatening symptoms, there are a number of foodborne infectious diseases and toxins that the emergency physician or other health care provider must consider in the evaluation of these patients. Given the frequency of international travel, as well as the risk associated with recurrent outbreaks of foodborne illness from commercial food sources, it is important to recognize various syndromes of foodborne illness, including those which may require specific evaluation and management strategies. This article reviews a number of the most common causes of foodborne illness, as well as several less common pathogens with the potential for causing significant morbidity and mortality if not promptly identified and treated.

CT imaging of acute E. Coli-related colitis

Patients with abdominal pain and bloody diarrhea often present in the acute setting to the emergency department for evaluation. After the appropriate clinical assessment, cross-sectional imaging is often utilized to evaluate for the severity of the disease. Although a wide spectrum of findings may be seen, diffuse colonic mural thickening, consistent with pancolitis, is most common. We report an Escherichia coli 0157:H7-related pancolitis in a patient with spinach intake linked to the recent outbreak.

Escherichia coli O157 infection mimicking acute appendicitis: usefulness of computed tomography for differential diagnosis

A 19-year-old man was admitted to our hospital with acute abdominal pain in the right lower quadrant. He had had mild diarrhea, of 1 day's duration, 2 days before admission. Although physical findings were consistent with a diagnosis of acute appendicitis, computed tomography findings showed marked wall thickening from the ascending colon to the cecum, findings which were similar to those in patients with hemorrhagic colitis due to Escherichia coli O157. Instead of emergency laparotomy, the patient was treated with antimicrobial agents, which led to rapid recovery. Diagnosis of intestinal infection due to E. coli O157 was established later, as serum antibody against lipopolysaccharide of E. coli O157 was positive. E. coli O157 infection should be included in the differential diagnosis of diseases that exhibit marked wall thickening of the right colon on CT in patients with acute abdominal pain in the right lower quadrant who have mild transient diarrhea.