David R. Cave

Oxalobacter formigenes May Reduce the Risk of Calcium Oxalate Kidney Stones

Most kidney stones are composed primarily of calcium oxalate. Oxalobacter formigenes is a Gram-negative, anaerobic bacterium that metabolizes oxalate in the intestinal tract and is present in a large proportion of the normal adult population. It was hypothesized that the absence of O. formigenes could lead to increased colonic absorption of oxalate, and the subsequent increase in urinary oxalate could favor the development of stones. To test this hypothesis, a case-control study involving 247 adult patients with recurrent calcium oxalate stones and 259 age-, gender-, and region-matched control subjects was performed. The prevalence of O. formigenes, determined by stool culture, was 17% among case patients and 38% among control subjects; on the basis of multivariate analysis controlling demographic factors, dietary oxalate, and antibiotic use, the odds ratio for colonization was 0.3 (95% confidence interval 0.2 to 0.5). The inverse association was consistently present within strata of age, gender, race/ethnicity, region, and antibiotic use. Among the subset of participants who completed a 24-h urine collection, the risk for kidney stones was directly proportional to urinary oxalate, but when urinary factors were included in the multivariable model, the odds ratio for O. formigenes remained 0.3 (95% confidence interval 0.1 to 0.7). Surprisingly, median urinary oxalate excretion did not differ with the presence or absence of O. formigenes colonization. In conclusion, these results suggest that colonization with O. formigenes is associated with a 70% reduction in the risk for being a recurrent calcium oxalate stone former.

A prospective study of the diagnostic accuracy of PillCam ESO esophageal capsule endoscopy versus conventional upper endoscopy in patients with chronic gastroesophageal reflux diseases

Introduction: Endoscopy is commonly performed to evaluate for suspected or established esophageal diseases including gastroesophageal reflux disease (GERD) and its complications. The newly developed PillCam ESO Esophageal Capsule offers an alternative approach to visualize the esophagus and to evaluate patients with suspected esophageal disease. Aim: Compare the accuracy (specificity, sensitivity, positive predictive value [PPV], and negative predictive value [NPV]) of esophageal capsule endoscopy (ECE) compared with esophagogastroduodenoscopy (EGD) in evaluating patients with GERD. Methods: A multicenter pivotal trial was conducted at seven sites. The PillCam ESO esophageal capsule is similar to the standard capsule endoscope used for the small bowel but acquires video images from both ends of the device at 2 frames/second/end. A total of 106 patients (93 GERD; 13 Barrett) underwent ECE followed by EGD. ECE videos were evaluated by an investigator blinded to EGD findings. A blinded adjudication committee reviewed all discrepant findings between ECE and EGD. Results: Sixty-six of 106 patients had positive esophageal findings, ECE identified esophageal abnormalities in 61 (sensitivity, 92%; specificity, 95%). The per-protocol sensitivity, specificity, PPV, and NPV of ECE for Barrett esophagus were 97%, 99%, 97%, and 99%, respectively, and for esophagitis 89%, 99%, 97%, and 94%, respectively. ECE was preferred over EGD by all patients. There were no adverse events related to ECE. Conclusions: ECE is a convenient and sensitive method for visualization of esophageal mucosal pathology and may provide an effective method to evaluate patients for esophageal disease.

Video capsule enteroscopy in the diagnosis of celiac disease : a multicenter study

OBJECTIVES:Duodenal biopsy is the current gold standard for diagnosis of celiac disease. Videocapsule endoscopy examines the entire small bowel and allows visualization of mucosal villi. We evaluated the potential of videocapsule endoscopy in assessing the severity and extent of mucosal changes in patients with suspected celiac disease.METHODS:Consecutive patients with signs/symptoms suggesting celiac disease and positive anti-gliadin and/or anti-endomysial and/or anti-tissue transglutaminase antibodies underwent upper gastrointestinal endoscopy and videocapsule endoscopy. Duodenal biopsies were classified according to modified Marshs criteria. Capsule findings were evaluated for the presence of lesions compatible with celiac disease (scalloping of duodenal folds, fissures, flat mucosa, and mosaic appearance).RESULTS:Forty-three patients were studied. Duodenal histology was normal in 11 and compatible with celiac disease in 32. Using duodenal histology as the gold standard, the performance characteristics of capsule endoscopy for the diagnosis of celiac disease were: sensitivity 87.5% (95% CI 76.1–98.9%), specificity 90.9% (95% CI 81.0–100%), positive predictive value 96.5% (95% CI 90.1–100%), negative predictive value 71.4% (95% CI 55.8–87%), positive and negative likelihood ratios 9.6 and 0.14, respectively. Eighteen patients had mucosal changes extending beyond the duodenum, involving the entire small bowel in three. These patients tended to have more severe symptoms, but the difference was not statistically significant. Interobserver agreement for the diagnosis of celiac disease by capsule endoscopy ranged between 79.2 and 94.4%; kappa values ranged between 0.56 and 0.87.CONCLUSIONS:Videocapsule endoscopy shows good sensitivity and excellent specificity for the detection of villous atrophy in patients with suspected celiac disease.

ACG Clinical Guideline: Diagnosis and Management of Small Bowel Bleeding

Bleeding from the small intestine remains a relatively uncommon event, accounting for ~5–10% of all patients presenting with gastrointestinal (GI) bleeding. Given advances in small bowel imaging with video capsule endoscopy (VCE), deep enteroscopy, and radiographic imaging, the cause of bleeding in the small bowel can now be identified in most patients. The term small bowel bleeding is therefore proposed as a replacement for the previous classification of obscure GI bleeding (OGIB). We recommend that the term OGIB should be reserved for patients in whom a source of bleeding cannot be identified anywhere in the GI tract. A source of small bowel bleeding should be considered in patients with GI bleeding after performance of a normal upper and lower endoscopic examination. Second-look examinations using upper endoscopy, push enteroscopy, and/or colonoscopy can be performed if indicated before small bowel evaluation. VCE should be considered a first-line procedure for small bowel investigation. Any method of deep enteroscopy can be used when endoscopic evaluation and therapy are required. VCE should be performed before deep enteroscopy if there is no contraindication. Computed tomographic enterography should be performed in patients with suspected obstruction before VCE or after negative VCE examinations. When there is acute overt hemorrhage in the unstable patient, angiography should be performed emergently. In patients with occult hemorrhage or stable patients with active overt bleeding, multiphasic computed tomography should be performed after VCE or CTE to identify the source of bleeding and to guide further management. If a source of bleeding is identified in the small bowel that is associated with significant ongoing anemia and/or active bleeding, the patient should be managed with endoscopic therapy. Conservative management is recommended for patients without a source found after small bowel investigation, whereas repeat diagnostic investigations are recommended for patients with initial negative small bowel evaluations and ongoing overt or occult bleeding.

Transmission and Epidemiology of Helicobacter pylori

Helicobacter pylori is one of the most common bacterial infections worldwide. However, the majority of those infected do not develop clinical manifestations of disease. This review discusses the epidemiology of the organism in terms of incidence and prevalence, the presumed means of transmission from person to person, and how typing of the organism has helped the epidemiologist. The epidemiology of disorders that are associated with H. pylori is also discussed.

Risk of early surgery for Crohn's disease: implications for early treatment strategies.

OBJECTIVES:In this study we aimed to define the rate of early surgery for Crohns disease and to identify risk factors associated with early surgery as a basis for subsequent studies of early intervention in Crohns disease.METHODS:We assembled a retrospective cohort of patients with Crohns disease diagnosed between 1991 and 1997 and followed for at least 3 yr, who were identified in 16 community and referral-based practices in New England. Chart review was performed for each patient. Details of baseline demographic and disease features were recorded. Surgical history including date of surgery, indication, and procedure were also noted. Risk factors for early surgery (defined as major surgery for Crohns disease within 3 yr of diagnosis, exclusive of major surgery at time of diagnosis) were identified by univariate analysis. Multiple logistic regression was used to identify independent risk factors.RESULTS:Of 345 eligible patients, 69 (20.1%) required surgery within 3 yr of diagnosis, excluding the 14 patients (4.1%) who had major surgery at the time of diagnosis. Overall, the interval between diagnosis and surgery was short; one half of all patients who required surgery underwent operation within 6 months of diagnosis. Risk factors identified by univariate analysis as significantly associated with early surgery included the following: smoking; disease of small bowel without colonic involvement; nausea and vomiting or abdominal pain on presentation; neutrophil count; and steroid use in the first 6 months. Disease localized to the colon only, blood in the stool, use of 5-aminosalicylate, and lymphocyte count were inversely associated with risk of early surgery. Logistic regression confirmed independent associations with smoking as a positive risk factor and involvement of colon without small bowel as a negative risk factor for early surgery.CONCLUSIONS:The rate of surgery is high in the first 3 yr after diagnosis of Crohns disease, particularly in the first 6 months. These results suggest that improved risk stratification and potent therapies with rapid onset of action are needed to modify the natural history of Crohns disease.

How is Helicobacter pylori Transmitted

Helicobacter pylori is one of the worlds most common pathogens. It colonizes about 60% of the worlds population, causes gastritis and peptic ulcer, and is strongly associated with gastric adenocarcinoma and lymphoma. However, most individuals never develop clinical disease. Thirteen years after the culture of H. pylori by Marshall and Warren, we still do not know its major mode of transmission. Childhood represents the major period of acquisition of infection in the third world, but infection is rare in children in the developed world. Possible routes of infection include either oral-oral or fecal-oral, iatrogenic spread with inadvertent use of unsterile pH probes and endoscopes, and vectorial spread by flies. Evidence to support each route of transmission is provided, but there is no predominant route. The only significant reservoir of infection appears to be humans themselves. The organism has been found in some domestic cats and in nonhuman primates, but the opportunities for human interaction with the latter are rare, making infection from this source an unlikely possibility. The organism has the propensity to become a coccoid form. This may represent a persistent form in which H. pylori can exist in the environment, but it has yet to be shown that it can revert to the replicative form.

Complications associated with double balloon enteroscopy at nine US centers.

BACKGROUND & AIMS Double balloon enteroscopy (DBE) was introduced into the US in 2004. Potential complications include perforation, pancreatitis, and gastrointestinal bleeding. Prevalence and risk factors for complications have not been described in a US population. METHODS We conducted a retrospective study of DBE complications in 9 US centers. We obtained detailed information for each complication including patient history, maneuvers performed during the DBE, and presence of altered surgical anatomy. RESULTS We collected data from 2478 DBE examinations performed from 2004 to 2008. The dataset included 1691 (68%) anterograde DBE, 722 (29%) retrograde DBE (including 5 per-stomal DBEs), and 65 (3%) DBE-facilitated endoscopic retrograde cholangiopancreatography ERCP cases. There were a total of 22 (0.9%) major complications including perforation in 11 (0.4%), pancreatitis in 6 (0.2%), and bleeding in 4 (0.2%) patients. One of 6 cases of pancreatitis occurred post retrograde DBE. Perforations occurred in 3/1691 (0.2%) anterograde examinations and 8/719 (1.1%) retrograde DBEs (P = .004). Eight (73%) perforations occurred during diagnostic DBE examinations. Four of 8 retrograde DBE perforations occurred in patients with prior ileoanal or ileocolonic anastomoses. In the subset of 219 examinations performed in patients with surgically altered anatomy, perforations occurred in 7 (3%), including 1/159 (0.6%) anterograde DBE examinations, 6/60 (10%) retrograde DBEs, and 1 of 5 (20%) peristomal DBE examinations (P < .005 compared with patients without surgically altered anatomy). CONCLUSIONS DBE is associated with a higher complication rate compared with standard endoscopic procedures. The perforation rate was significantly elevated in patients with altered surgical anatomy undergoing diagnostic retrograde DBE examinations.

A multicenter randomized comparison of the Endocapsule and the Pillcam SB

BACKGROUND Video capsule endoscopy has been shown to be the single most effective endoscopic procedure for identifying the source of obscure GI bleeding (OGIB). OBJECTIVE Our purpose was to report on the Food and Drug Administration pivotal trial in which the Endocapsule (EC) (Olympus America, Allentown, Pa) was compared with the Pillcam SB (PSB) (Given Imaging, Yoqneam, Israel) in patients with OGIB. DESIGN A novel trial design was used in which the EC and the PSB were swallowed by the same patient 40 minutes apart, in randomized order. SETTING Four academic medical centers. PATIENTS Patients with OGIB aged 18 to 85 years who had either been transfused or who had a hematocrit of <31% in males or <28% in females. INTERVENTIONS Both video capsules were swallowed in random order. Videos from the PSB were read locally for patient management. All videos were then read by at least 2 independent readers for normal versus abnormal categorization, a diagnosis, capsule transit time, reading time, and a subjective assessment of image quality. MAIN OUTCOME MEASUREMENT Categorization of videos as either normal or abnormal. RESULTS Data from 51 of 63 enrolled patients were analyzed. Nine patients were excluded for technical reasons and 3 for protocol violations. Twenty-four videos were read as normal and 14 as abnormal from both capsules. Disagreement occurred in 13. No adverse events were reported for either capsule. Overall agreement was 38 of 51 (74.5%) with a kappa of 0.48, P = .008. LIMITATIONS Although ingestion order was randomized, the videos could not be read blind owing to a different shape of the image margin. CONCLUSIONS (1) Both devices were safe and had a comparable diagnostic yield within the range previously reported. (2) There was a subjective difference in image quality favoring the EC. (3) This study design provided unique information about capsule movement in the small intestine and the lack of electromechanical interference between 2 different capsules.

Necrotizing fasciitis following percutaneous endoscopic gastrostomy

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