DETECTING NUCLEAR MATERIALS IN URBAN ENVIRONMENTS USING MOBILE SENSOR NETWORKS

Radiation detectors installed at major ports of entry are a key component of the overall strategy to protect countries from nuclear terrorism. While the goal of deploying these systems is to intercept special nuclear material as it enters the country, no detector system is fool proof. Mobile, distributed sensors have been proposed to detect nuclear materials in transit should portal monitors fail to prevent their entry in the first place. In large metropolitan areas a mobile distributed sensor network could be deployed using vehicle platforms such as taxis, Ubers and Lyfts which are already connected to communications infrastructure. However, the potential geographic coverage that could be achieved using a network of sensors mounted on commercial passenger vehicles has not been established. Here we evaluate how a mobile sensor network could perform in New York City using a combination of radiation transport and Geographic Information Systems. The Geographic Information System QGIS is used in conjunction with OpenStreetMap data to isolate roads and construct a grid over the streets. Vehicle paths are built using pickup and drop off data from Uber, and data from the New York State Department of Transportation.

Real-world multicentre experience of the pathological features of colonic ischaemia and their relationship to symptom duration, disease distribution and clinical outcome

AIM

To determine the pathological features of colonic ischaemia (CI) and their relationship to symptom duration, disease distribution and clinical outcome in a real-world, clinical setting.

METHOD

A retrospective, multicentre chart review was performed in patients diagnosed with CI at Montefiore Medical Center (January 2005 to July 2015), and Yale-New Haven Hospital (January 2005 to June 2010). Patients were included if clinical presentation, colonoscopic findings and colonic pathology were all consistent with CI.

RESULTS

Six hundred and sixteen patients with pathologically proven CI were included. Common pathological findings included inflammation (51.1%), ulceration (38.2%), fibrosis (26.0%) and necrosis (20.4%). Infarction and ghost cells were seen in 1.6% and 0.2% of cases, respectively. There was a significant relationship between symptom duration and hyalinization of the lamina propria (P = 0.05) and cryptitis/crypt abscesses (P = 0.01). Patients with isolated right CI (IRCI) were more likely than patients with isolated left CI (ILCI) to exhibit necrosis (P < 0.01), cryptitis/crypt abscess (P < 0.01) and inflammation (P = 0.03). Patients with poor outcomes were more likely to exhibit necrosis (P < 0.01) and capillary fibrin thrombi (P < 0.01) and less likely to exhibit fibrosis (P < 0.01) and epithelial changes (P < 0.01).

CONCLUSION

CI is accompanied by a broad spectrum of pathological findings. The traditional pathognomonic findings of CI are rare and cannot be relied upon to exclude the diagnosis. Patients with IRCI and/or poor outcomes were more likely to have pathological findings of necrosis than patients who had ILCI and/or nonpoor outcomes.

The Role of Stress, Social Support, and Family Environment in Adolescent Mothers' Parenting

This study assessed the role of stress, social support, and family environment on adolescent mothers'parenting behaviors. Seventy-five African American, mother-infant pairs participated in the study. Mothers were administered questionnaires and were each observed in a 10-minute teaching task with their babies. Findings revealed that the adolescent mother's own mother was the mostfrequent provider of support. The baby's fatherwas identified as the mostfrequent source of conflict. Mothers who identified more individuals as a source of conflict tended to have less positive parenting behaviors. Analyses revealed that child age and interpersonal conflict were significant predictors of maternal behavior In addition, social support moderated the effects of interpersonal conflict when conflicted networks were large. Parenting stress, per se, was not a significant predictor of maternal behavior.

"We Are Now Free to Speak": Qualitative Evaluation of an Education and Empowerment Training for HIV Patients in Namibia

Although numerous studies provide evidence that active patient engagement with health care providers improves critical outcomes such as medication adherence, very few of these have been done in low resource settings. In Namibia, patient education and empowerment trainings were conducted in four antiretroviral (ART) clinics to increase patient engagement during patient-provider interactions. This qualitative study supplements findings from a randomized controlled trial, by analyzing data from 10 in-depth patient interviews and 94 training evaluation forms. A blended approach of deductive and inductive coding was used to understand training impact. Findings indicated the trainings increased patients’ self-efficacy through a combination of improved HIV-related knowledge, greater communication skills and enhanced ability to overcome complex psychosocial barriers, such as fear of speaking up to providers. This study suggests patient empowerment training may be a powerful method to engage HIV patients in their own care and treatment.

Evaluating the effectiveness of patient education and empowerment to improve patient-provider interactions in antiretroviral therapy clinics in Namibia

In order to increase patient active engagement during patient-provider interactions, we developed and implemented patient training sessions in four antiretroviral therapy (ART) clinics in Namibia using a "Patient Empowerment" training curriculum. We examined the impact of these trainings on patient-provider interactions after the intervention. We tested the effectiveness of the intervention using a randomized parallel group design, with half of the 589 enrolled patients randomly assigned to receive the training immediately and the remaining randomized to receive the training 6 months later. The effects of the training on patient engagement during medical consultations were measured at each clinic visit for at least 8 months of follow-up. Each consultation was audiotaped and then coded using the Roter Interaction Analysis System (RIAS). RIAS outcomes were compared between study groups at 6 months. Using intention-to-treat analysis, consultations in the intervention group had significantly higher RIAS scores in doctor facilitation and patient activation (adjusted difference in score 1.19, p = .004), doctor information gathering (adjusted difference in score 2.96, p = .000), patient question asking (adjusted difference in score .48, p = .012), and patient positive affect (adjusted difference in score 2.08, p = .002). Other measures were higher in the intervention group but did not reach statistical significance. We have evidence that increased engagement of patients in clinical consultation can be achieved via a targeted training program, although outcome data were not available on all patients. The patient training program was successfully integrated into ART clinics so that the trainings complemented other services being provided.

Is fecal microbiota transplantation (FMT) an effective treatment for patients with functional gastrointestinal disorders (FGID)?

BACKGROUND

Despite its high prevalence and significant effect on quality of life, the etiology of functional gastrointestinal disorders (FGID), and specifically irritable bowel syndrome (IBS), has yet to be fully elucidated. While alterations in immunity, motility, and the brain-gut axis have been implicated in disease pathogenesis, the intestinal microbiota are increasingly being shown to play a role and numerous studies have demonstrated significant differences from normal in the intestinal flora of patients with FGID, and between types of FGID. Fecal microbiota transplantation (FMT) is a curative therapy for Clostridium difficile infection (CDI), a disease hallmarked by intestinal dysbiosis, and FMT is now being explored as a means to also restore intestinal homeostasis in FGID.

PURPOSE

This review aims to investigate the role of intestinal microbiota in the pathogenesis of FGID, the implications of FMT for the treatment of FGID, and the challenges encountered in measuring response to a specific intervention in patients with FGID.

The efficacy of probiotics in the treatment of irritable bowel syndrome: a systematic review

INTRODUCTION

Probiotics may benefit irritable bowel syndrome (IBS) symptoms, but randomised controlled trials (RCTs) have been conflicting; therefore a systematic review was conducted.

METHODS

MEDLINE (1966 to May 2008), EMBASE (1988 to May 2008) and the Cochrane Controlled Trials Register (2008) electronic databases were searched, as were abstracts from DDW (Digestive Diseases Week) and UEGW (United European Gastroenterology Week), and authors were contacted for extra information. Only parallel group RCTs with at least 1 week of treatment comparing probiotics with placebo or no treatment in adults with IBS according to any acceptable definition were included. Studies had to provide improvement in abdominal pain or global IBS symptoms as an outcome. Eligibility assessment and data extraction were performed by two independent researchers. Data were synthesised using relative risk (RR) of symptoms not improving for dichotomous data and standardised mean difference (SMD) for continuous data using random effects models.

RESULTS

19 RCTs (18 papers) in 1650 patients with IBS were identified. Trial quality was generally good, with nine reporting adequate methods of randomisation and six a method of concealment of allocation. There were 10 RCTs involving 918 patients providing outcomes as a dichotomous variable. Probiotics were statistically significantly better than placebo (RR of IBS not improving=0.71; 95% CI 0.57 to 0.88) with a number needed to treat (NNT)=4 (95% CI 3 to 12.5). There was significant heterogeneity (chi(2)=28.3, p=0.001, I(2)=68%) and possible funnel plot asymmetry. Fifteen trials assessing 1351 patients reported on improvement in IBS score as a continuous outcome (SMD=-0.34; 95% CI -0.60 to -0.07). There was statistically significant heterogeneity (chi(2)=67.04, p<0.001, I(2)=79%), but this was explained by one outlying trial.

CONCLUSION

Probiotics appear to be efficacious in IBS, but the magnitude of benefit and the most effective species and strain are uncertain.

Review article: diagnosis and management of mesenteric ischaemia with an emphasis on pharmacotherapy

Mesenteric ischaemia results from decreased blood flow to the bowel, causing cellular injury from lack of oxygen and nutrients. Acute mesenteric ischaemia (AMI) is an uncommon disorder with high morbidity and mortality, but outcomes are improved with prompt recognition and aggressive treatment. Five subgroups of AMI have been identified, with superior mesenteric artery embolism (SMAE) the most common. Older age and cardiovascular disease are common risk factors for AMI, excepting acute mesenteric venous thrombosis (AMVT), which affects younger patients with hypercoaguable states. AMI is characterized by sudden onset of abdominal pain; a benign abdominal exam may be observed prior to bowel infarction. Conventional angiography and more recently, computed tomography angiography, are the cornerstones of diagnosis. Correction of predisposing conditions, volume resuscitation and antibiotic treatment are standard treatments for AMI, and surgery is mandated in the setting of peritoneal signs. Intra-arterial vasodilators are used routinely in the treatment of non-occlusive mesenteric ischaemia (NOMI) and also are advocated in the treatment of occlusive AMI to decrease associated vasospasm. Thrombolytics have been used on a limited basis to treat occlusive AMI. A variety of agents have been studied in animal models to treat reperfusion injury, which sometimes can be more harmful than ischaemic injury. Chronic mesenteric ischaemia (CMI) usually is caused by severe obstructive atherosclerotic disease of two or more splanchnic vessels, presents with post-prandial pain and weight loss, and is treated by either surgical revascularization or percutaneous angioplasty and stenting.

Infectious diarrhea in the elderly

Infectious diarrhea is an important disease in the elderly. Some basic principles have been outlined, as follows. In the elderly: Infectious diarrhea is an underappreciated health problem. There is a higher mortality rate and case-fatality rate compared with younger persons. Infectious diarrhea is most often associated with group settings (e.g., nursing homes and skilled nursing facilities) or antibiotic use. Infectious diarrhea may be associated with abnormal immune function (i.e., immunosenescence). Certain bacterial infections are commoner (e.g., C. difficile, E. coli O157:H7, and Salmonella). Some infections behave differently (e.g., Salmonella). Prompt and adequate rehydration measures are crucial. The institution of appropriate contact isolation and infection control measures is crucial in group settings.

Patient referral patterns in Namibia: identification of potential to improve the efficiency of the health care system

In order to assess how the hospital referral system in Namibia was operating, a cross-sectional survey of patients attending three intermediate hospitals and the national hospital was conducted over a 4-week period. The survey was planned by a Ministry of Health and Social Services' working group, with technical support provided by a donor funded health programme. Together with complementary qualitative data, obtained through focus group discussions with the community, the survey generated information on the extent to which the referral system was being bypassed, the types of bypassing and related factors. These included reasons for non-compliance with referral to the intermediate hospitals, perceived barriers to their utilization and community preparedness to use these hospitals after upgrading. The results were used to inform decisions about the classification of the three hospitals and identification of their catchment areas. The results were also shown to be useful for assessing the likely impact of different strategies for reducing bypassing. In Namibia these impacts were expected to be limited, due to the influence of distance and low population densities. Information on the extent and types of bypassing taking place across districts is essential for assessing opportunities to improve the functioning of a pyramidal referral system, which supports a cost-effective primary health care strategy.

Ischemic bowel disease in the elderly

The ischemic bowel diseases are a heterogeneous group of disorders usually seen in elderly individuals. They represent ischemic damage to different portions [figure: see text] of the bowel and produce a variety of clinical syndromes and outcomes. Colonic ischemia is the commonest of these disorders and has a favorable prognosis in most cases. In contrast, acute mesenteric ischemia, most commonly caused by a superior mesenteric artery embolus, is a disease with a poor prognosis. Acute mesenteric ischemia secondary to nonocclusive mesenteric ischemia usually is a [figure: see text] catastrophic complication of other severe medical illnesses, most notably atherosclerosis. Proper diagnosis and management of patients with ischemic bowel disease requires vigilance on the part of the physician and a willingness to embark on an aggressive plan of diagnosis and management in the appropriate setting.

AGA technical review on intestinal ischemia. American Gastrointestinal Association

This literature review and the recommendations therein were prepared for the American Gastroenterological Association Clinical Practice and Practice Economics Committee. The paper was approved by the committee on September 25, 1999, and by the AGA Governing Board on November 25, 1999.

Clostridium difficile-associated diarrhea in the elderly

OBJECTIVE

It is widely believed that Clostridium difficile (C. difficile)-associated diarrhea is a more severe disease in the elderly than in the young, associated with increased morbidity and mortality. These beliefs are largely anecdotal, and there are few data supporting them.

METHODS

We conducted an evaluation in an urban, tertiary care hospital of 89 inpatients in whom C. difficile-associated diarrhea was identified. These patients were evaluated prospectively, and the group was divided by age into those < 60 yr of age (younger) and those > or = 60 yr (elderly).

RESULTS

There was no difference in mortality or morbidity in elderly individuals with C. difficile-associated diarrhea when compared with younger persons similarly infected. The response to standard treatment was similar in both groups. Older patients were more likely to have an elevated white blood cell count in association with C. difficile-associated diarrhea (60% vs 26%, p < 0.05), and were more likely to have acquired their infection in the hospital (89% vs 50%, p < 0.0001).

CONCLUSIONS

In the elderly, C. difficile-associated diarrhea is almost always acquired in institutions, and may not be obvious among patients' other problems. The elderly do not seem to have an increase in C. difficile diarrhea-associated morbidity or mortality. There is no evidence that C. difficile-associated diarrhea is more severe in the elderly than it is in the young.

Pneumatosis intestinalis complicating C. difficile pseudomembranous colitis

Pneumatosis intestinalis (PI) is characterized by multiple gas-filled cysts or linear gas within the bowel wall. PI may be idiopathic (15%) or secondary (85%) to a variety of disorders. We report here the first otherwise healthy adult with C. difficile infection complicated by PI and review the possible mechanisms of this previously unrecognized complication of pseudomembranous colitis. With treatment of the underlying infection, the PI resolved within 6 days of presentation.

Parasitic infections of the gastrointestinal tract

Parasitic infections of the gastrointestinal tract are a major cause of morbidity and mortality worldwide. Increased international travel means that gastroenterologists are now more likely to care for patients with parasitic diseases. This article reviews various aspects of the more common intestinal parasites and their infections, including epidemiology, life cycle, pathogenesis, clinical manifestations, diagnosis, and treatment.

Colon Ischemia

Colon ischemia is expressed in a broad clinical spectrum, from mild, reversible ischemia to intestinal infarction and gangrene. In most cases, the precipitating cause is unknown, and colonic blood flow usually has normalized by the time the patient seeks medical attention. Satisfactory treatment begins with accurate diagnosis, which depends on serial colonoscopic or roentgenographic studies and the exclusion of other disorders that may mimic colon ischemia. Prognosis typically is good, and most patients require only supportive care with close follow-up. More aggressive therapy, including surgery, is indicated in patients who early in their course develop massive bleeding, perforation, or signs of fulminant colitis or who subsequently develop symptomatic strictures or persistent symptoms of colitis.

Hyperbaric oxygen therapy for perineal Crohn's disease

Perineal lesions are a frequent and troublesome complication of Crohn's disease. Although there are various surgical and medical therapeutic regimens available to treat these lesions, all have significant associated morbidity, mortality, and toxicity. Recently, the beneficial effects of hyperbaric oxygen therapy (HBOT) have been described in patients with severe or refractory perineal disease, but the role of HBOT in larger groups or less severely affected patients has not yet been studied, nor has the minimum number of treatments required for initial or complete healing of perineal disease in this population been described. This article reviews the known and theoretical tissue effects of HBOT and discusses its potential role in treating patients with perineal Crohn's disease.

Ability of naloxone to enhance the colonoscopic appearance of normal colon vasculature and colon vascular ectasias

BACKGROUND

Colon vascular ectasias are a common cause of lower intestinal bleeding among the elderly. The lesions may be difficult to diagnose at colonoscopy because they are small and their appearance may be influenced by the patient's blood pressure, blood volume, and narcotic sedation during the procedure. The purpose of this study was to determine whether naloxone influenced the appearance of colon vascular ectasias at colonoscopy.

METHODS

One hundred forty-four patients older than 60 years undergoing complete colonoscopy participated in the study. Medications were given in the usual doses. After a 2-minute inspection of the cecum and ascending colon, naloxone was given, followed by another 2-minute observation period. Photographic documentation of areas of interest was obtained before and after administration of naloxone.

RESULTS

One hundred fourteen patients (79%) had no ectasias before or after administration of naloxone. Fourteen (9.7%) initially had normal vessels, and the vessels became more prominent; 4 (2.7%) initially had no ectasias, but ectasias later developed. Four patients (2.7%) had ectasias before administration of naloxone that did not change; 8 (5.4%) had ectasias before administration of naloxone that increased in size (3 patients), number (7 patients), or both (2 patients).

CONCLUSIONS

Naloxone can enhance the appearance of normal colonic vasculature and ectasias. Naloxone is an important adjunctive medication for patients undergoing examinations for lower intestinal bleeding.

Cytologic detection of Trichomonas esophagitis in a patient with acquired immunodeficiency syndrome

Trichomonads are pathogens of the female genital tract and colonizers of the oropharynx. Gastrointestinal and pulmonary diseases have been reported in association with Trichomonas species, but a direct pathogenic effect of this organism in these organ systems remains controversial. Esophageal disease due to trichomonads has not been previously reported. A 43-yr-old man with acquired immunodeficiency syndrome (AIDS) with odynophagia and esophageal erosions was evaluated by endoscopy. Cytologic brushings from three of four sites in the esophagus were positive for trichomonads. Treatment with metronidazole resulted in clearance of the organism from the esophagus and improvement in clinical symptoms. We report esophageal trichomoniasis diagnosed on esophageal brush cytology in a man with AIDS. Clinical response was confirmed by cytologic studies and odynophagia improved with metronidazole treatment. Study of cytologic preparations was superior to biopsy for identification of this organism and was particularly useful in following the post-treatment course of disease.

Gastrointestinal bleeding in AIDS

Gastrointestinal (GI) bleeding is an uncommon manifestation of AIDS despite the frequent involvement of the GI tract by infections, malignancies, and a variety of other disorders. GI bleeding may occur from a variety of causes, some specifically associated with AIDS and others unrelated to immunocompromise; most patients with AIDS who have lower GI bleeding have causes attributable to AIDS-specific lesions. Just as in an incompetent patient, an aggressive approach to diagnosis and treatment of GI bleeding in AIDS patients is warranted.

Colonic ischemia

Colonic ischemia encompasses a wide clinical spectrum from mild, reversible disease to severe, irreversible injury. It is a frequent disorder of the large bowel in the elderly, and can mimic certain diseases such as inflammatory bowel disease and neoplasms. The clinical course is variable, but often includes crampy, lower abdominal pain and the passage of red or maroon blood mixed with stool. In most cases, management is expectant, with supportive care and attention for signs of complicated disease. Prognosis typically is favorable, with a majority of patients completely resolving their illness; a minority go on to develop irreversible injury including strictures and chronic segmental colitis. Successful management of a patient with ischemic colitis requires a high degree of clinical suspicion, early diagnosis, careful follow-up, and prompt recognition of persistent disease.

The immunohistological diagnosis of E. coli O157:H7 colitis: possible association with colonic ischemia

OBJECTIVE

E. coli O157:H7 may cause hemorrhagic colitis resembling ischemic colitis. Diagnosis is usually made by finding sorbitol-negative colonies on MacConkey agar that react with O157 and H7 antisera. Most ischemic colitis is idiopathic, but some may be caused by E. coli O157:H7, inasmuch as this organism can produce fibrin thrombi in colon vasculature. The objectives of this study were to determine whether E. coli O157:H7 infection can be diagnosed retrospectively from paraffin blocks of colon sections and whether an association exists between E. coli O157:H7 infection and colonic ischemia.

METHODS

Paraffin-embedded sections of normal colon (n = 2) and various colitides [ischemic (n = 11), E. coli O157:H7 (n = 2), IBD (n = 8) and pseudomembranous (n = 3)] were used. Sections were deparaffinized, rehydrated, incubated with 3% peroxide in methanol, rinsed, and incubated with peroxidase-labeled antibody isolated from goats immunized with whole E. coli O157:H7. Sections were stained with peroxidase chromagen reagent and counterstained with hematoxylin. Coarse, granular, orange-brown staining was considered positive. To determine the localization of the chromagen deposits, three cases that stained positive, including one of the culture-proved E. coli O157:H7 colitis and two of colonic ischemia, were processed for electron microscopy.

RESULTS

Both cases (100%) of E. coli O157:H7 colitis and three of 11 (27.3%) cases of ischemic colitis stained positive by light microscopy. In one culture-proved case, electron microscopy demonstrated staining of bacillary structures; in two cases of colonic ischemia, extensive deposits of chromagen material were present that were associated neither with inflammatory cells nor with bacterial forms.

CONCLUSIONS

Immunoperoxidase staining of archival sections may be used to diagnose E. coli O157:H7 infection. An etiological role for this organism is possible in some cases of colonic ischemia.

A double-blind placebo-controlled pilot study of glutamine therapy for abnormal intestinal permeability in patients with AIDS

OBJECTIVES

Up to 20% of patients with AIDS have abnormal intestinal permeability (IP). Glutamine seems to play an important role in preventing the increase in IP and loss of intestinal mucosal mass associated with total parenteral nutrition, and may be superior to glucose for oral rehydration in the setting of intestinal infection. This study was designed to see if supplemental glutamine could alter the abnormal IP of AIDS.

METHODS

Randomly chosen patients with AIDS from the Jacobi Medical Center human immunodeficiency virus (HIV) clinic underwent IP testing using lactulose and mannitol. Those with abnormal IP were enrolled. Duodenal biopsies were performed with a Crosby capsule and the patients were randomized in a double-blind fashion to receive placebo or glutamine (4 g/day or 8 g/day) for 28 days, after which intestinal permeability tests and duodenal biopsies were repeated. Intestinal morphology was graded by ratio of villus height to crypt depth, and by degree of inflammation.

RESULTS

All patients complied with the therapy and there were no dropouts or reported side effects. The results showed less worsening of IP with the 4 g/day dose, compared with placebo. At the 8 g/day dose, there was stabilization of IP and improved absorption of mannitol. Intestinal morphology and inflammation did not change in any group.

CONCLUSIONS

These results, although not significant, suggest a trend towards improved IP and enhanced intestinal absorption with glutamine. Glutamine doses of at least 20 g/day may be necessary to improve IP. We recommend further studies at higher doses and for longer durations.

Pneumatosis intestinalis and AIDS: a case report and review of the literature

We report five AIDS patients who developed pneumatosis intestinalis and review the pertinent literature to clarify the contributory importance of underlying infections, to suggest a management plan, and to determine whether pneumatosis intestinalis alters prognosis. Of the five patients reported, three had concurrent infections including cryptosporidiosis (one patient), presumptive CMV (one patient), and toxoplasmosis of the central nervous system (one patient). One patient also had neutropenia. Another patient was immunosuppressed during treatment for lymphoma, and the fifth patient had been taking corticosteroids before the diagnosis of CNS lymphoma. In four of five patients pneumatosis involved the right colon. Pneumatosis was linear in all five patients and also was cystic in two of the five. All patients were followed conservatively without short term adverse events, despite the known association of linear pneumatosis with bowel necrosis. We advocate conservative management and an attempt to avoid surgery whenever possible.

Recognizing E. coli O157:H7 infection

This infection first surfaced as a U.S. public health problem in the early 1980s. The problem persists, in the United States and elsewhere. Illness may resemble that in other infectious colitides and should be considered in the differential diagnosis of ischemic colitis. Prompt diagnosis may be made by specific stool culture.

Bleeding causing biliary obstruction after endoscopic sphincterotomy

A 68-yr-old woman who had had a cholecystectomy and endoscopic sphincterotomy developed recurrent common bile duct obstruction. She had another ERCP with extension of the site of endoscopic sphincterotomy, and 3 days later biliary obstruction again developed, this time from a blood clot filling the common bile duct. The clot was removed by Fogarty technique, and the duct was irrigated with heparin; the obstruction resolved. Minor hemobilia (biliary tract hemorrhage without overt GI bleeding) may be confused with choledocholithiasis. When biliary obstruction follows endoscopic sphincterotomy, attempts at flushing the duct should precede empiric maneuvers for stone removal.

History of mesenteric ischemia. The evolution of a diagnosis and management

This article has traced the evolution of our knowledge of mesenteric ischemia from the initial stage of recognition of the condition and its manifestations, through the phase of treatment after the fact-resection of gangrenous intestine, to our present-day attempts to diagnose and treat the ischemic episode before death of the bowel and patient occurs. It is history from the authors' perspective, and because of limitations of space it is, perforce, highly selective. Hundreds of valuable contributions could not be included, and their omission in no way detracts from their importance. A number of surgeons, including Williams and Bergen in this country, Marston in England, Saegesser in Switzerland, and Kieny in France, have made mesenteric ischemia a major focus of their careers and have published extensively on it. The first book devoted to all aspects of mesenteric ischemia, Vascular Disorders of the Intestines edited by Boley, Schwartz, and Williams, was published in 1971. Since that time a number of books and monographs have chronicled progress in the field. Together these references make a good foundation for newly interested investigators in the subject. The results of diagnosis and management of mesenteric ischemia have improved significantly over the past 100 years but remain poor. The best part of the history of mesenteric ischemia remains to be written.

A preliminary study of patients' concerns related to GI endoscopy

OBJECTIVES

In addition to the well known complications of bleeding and perforation, GI endoscopy also can produce discomfort, anxiety, and dissatisfaction. In this pilot study, our objective was to obtain information on the fears and concerns of patients about to undergo endoscopy and to assess the relationship of such worries to patient satisfaction and difficulty with the procedure.

METHODS

At our two referral hospitals, 793 unsedated patients (45% men, 55% women, average 58 yr) were interviewed by GI nurses before the intended procedure. Information on procedure-related concerns and difficulty/satisfaction with the procedure was obtained.

RESULTS

Sixty percent of our sample reported preprocedure concerns, most often: 1) finding out what is wrong (18%); 2) pain (12%); and 3) finding cancer (4%). New York patients were more concerned than North Carolina patients with finding out what was wrong (23 vs 12%) although patients at both sites were equally concerned about having pain during the procedure (12%); women (16%), younger patients (16%), and those about to have their first procedure (17%) reported more concerns about pain. Regression analysis indicated that women and persons having no or fewer procedures were more likely to report a concern. Having had previous endoscopic procedures predicted greater satisfaction with subsequent endoscopies. Finally, a high level of preprocedure concerns was associated with perceived difficulties related to the procedure.

CONCLUSIONS

We believe that, by considering patient demographics, asking about previous experiences with endoscopy, and eliciting special concerns, the nurse or physician can focus patient education in a fashion that may reduce anticipatory anxiety.

Results of a survey to evaluate whether vaginal delivery and episiotomy lead to perineal involvement in women with Crohn's disease

OBJECTIVE

Crohn's disease frequently affects the perineum, but it is unknown if such involvement poses a heightened risk to a woman with Crohn's disease undergoing vaginal delivery and possibly episiotomy. This study attempts to elucidate whether vaginal delivery with or without episiotomy: 1) predisposes to perineal involvement in women with Crohn's disease; 2) reactivates quiescent perineal Crohn's disease; or 3) worsens preexisting perineal Crohn's disease.

METHODS

Data were culled from questionnaires returned by 117 respondents contacted through newsletters of the Crohn's and Colitis Foundation of America. These surveys were then reviewed and tabulated to determine if any temporal and causal relationship existed between perineal Crohn's disease and vaginal delivery.

RESULTS

Four groups were identified: group 1 (n = 56), with 128 pregnancies, had no history of perineal disease or subsequent perineal complication. Group 2 (n = 24) had 51 pregnancies. This group had no preexisting perineal disease, but 67.6% said they developed perineal Crohn's disease postpartum, 60% of which occurred within 2 months of vaginal delivery. Groups 3 and 4 were too small to evaluate (n = 4 and 5, respectively) and represented patients with preexisting perineal disease who had varying results after delivery. Overall, the rate of developing perineal involvement after vaginal delivery, usually with episiotomy, in patients with Crohn's disease and no preexisting perineal involvement (combining groups 1 and 2) was 17.9%.

CONCLUSIONS

A high rate of perineal involvement seems to follow vaginal delivery with episiotomy in patients with Crohn's disease. Although this study has substantial methodological limitations, it does raise questions as to the proper obstetrical management of patients with Crohn's disease and highlights an intriguing relationship that deserves further and more rigorous study.

Escherichia coli O157:H7 infection in humans

OBJECTIVE

To review the clinical relevance of Escherichia coli O157:H7 infection, including the epidemiology of the infection and its clinical presentations, pathogenesis, microbiology, diagnosis, treatment, and prevention.

DATA SOURCES

Articles on E. coli O157:H7 were identified through MEDLINE and the bibliographies of relevant articles.

STUDY SELECTION

All articles and case reports describing E. coli O157:H7 and its infection were selected.

DATA EXTRACTION

The data were abstracted without judgments about study design. Data quality and validity were assessed by independent author reviews.

DATA SYNTHESIS

Infection with E. coli O157:H7 presents with a wide spectrum of clinical manifestations, including asymptomatic carriage, nonbloody diarrhea, hemorrhagic colitis, the hemolytic-uremic syndrome, and thrombotic thrombocytopenic purpura. Not only is E. coli O157:H7 an important agent for hemorrhagic colitis, it is also one of the leading causes of bacterial diarrhea. Patients at extremes of age have an increased risk for infection and associated complications. Transmission of E. coli O157:H7 is primarily food-borne. Undercooked meat is the most common culprit, and secondary person-to-person spread is also important. The organism produces at least two Shiga-like toxins that differ antigenically, physicochemically, immunologically, and in their biological effects. These toxins are thought to have direct pathogenic significance in E. coli O157:H7 infection. This infection is usually diagnosed from a positive stool culture, from the presence of Shiga-like toxins, or both. Timely collection (within 7 days of illness onset) of a stool sample for culture is imperative for a high recovery rate. Treatment is primarily supportive and includes the management of complications as necessary. Antibiotic therapy has not been proved beneficial. Important public health measures include educating the public on the danger of eating undercooked meat, increasing physician awareness of E. coli O157:H7 infection, and mandating case reporting.

CONCLUSIONS

Infection with E. coli O157:H7 presents with many clinical manifestations and should be included in the differential diagnosis for any patient with new-onset bloody diarrhea. Development of the hemolytic-uremic syndrome or thrombotic thrombocytopenic purpura should raise strong suspicion of E. coli O157:H7 infection and should lead to prompt evaluation. If infection is confirmed, it should be reported to public health officials.

Informed consent: a survey of physician outcomes and practices

We mailed a survey to the domestic membership of the American Society of Gastrointestinal Endoscopy in an attempt to investigate how endoscopists obtained informed consent and the effect of these practices on medical malpractice claims. One thousand two hundred thirty-two (23.8%) surveys were returned. We determined that although informed consent is obtained in 98.5% of endoscopic cases, 30% of physicians leave the task of obtaining such consent to hospital or office personnel. Although endoscopists tend to be complete in terms of describing the risks of procedures to patients, all risks are not revealed equally; some complications, for example, the risk for requiring a colostomy, are disclosed by relatively few physicians, perhaps revealing a higher comfort level with a particular procedure, such as colonoscopy. Likewise, endoscopists generally explain the benefits of and alternatives to procedures, but they do not explain the more hazardous alternatives. Documentation of the informed consent process is an area in which physicians could be more thorough. Twenty-one percent of respondents had been sued, and in 42% of these instances, the informed consent process was an issue. Lawsuits in general (38%) changed the way respondents obtained consent, especially (64%) when this process had been an issue in the suit. No correlation was found between either the thoroughness of the informed consent process or the status of the person who obtained consent and the likelihood of being sued.

Mesenteric venous thrombosis

Mesenteric venous thrombosis (MVT) and its clinical expressions have become better defined as a result of improvements in both diagnostic imaging and our understanding of the various intestinal ischemic syndromes. Acute, subacute, and chronic forms of MVT are currently recognized, and these forms may differ in the symptoms they produce, the methods by which they are diagnosed, and the treatments they may require. Moreover, an underlying disease that predisposes a patient to MVT can be found in most instances.

Esophageal motility in AIDS patients with symptomatic opportunistic infections of the esophagus

OBJECTIVES

In patients with AIDS, esophageal symptoms are commonly due to opportunistic esophageal infection with Candida, cytomegalovirus (CMV), herpes simplex virus (HSV), and HIV. Despite apparently appropriate therapy against these pathogens, some patients continue to complain of dysphagia or odynophagia. This study was designed to determine whether such complaints were associated with a motility disorder of the esophagus.

METHODS

Sixteen patients underwent esophagoscopy and biopsy followed by esophageal manometry, performed using a 5-channel water perfused system (Synectics Medical, Inc., Irving, Texas). All patients had odynophagia, and eight had dysphagia.

RESULTS

Identified infections included: Candida (11), HSV and Candida (1), CMV (3), and a giant ulcer presumably caused by HIV (1); one patient also had lymphoma. Seven patients had normal esophageal motility, and in nine patients, a nonspecific motility disorder was found. After therapy, one of 10 patients had persistent odynophagia and dysphagia, and two had odynophagia only. At follow-up endoscopy, complete healing was demonstrated in six of eight patients with Candida. One of two patients with CMV and the patient with HSV also showed complete healing of the esophagus. Repeat esophageal motility studies were performed after therapy in 10 patients. Five had a persisting abnormality despite eradication of the pathogen (three Candida, one HSV, one CMV); in four, the previously identified motor abnormalities resolved after eradication of the infection (three Candida, one CMV).

CONCLUSIONS

These findings suggest that a nonspecific motility disorder exists in AIDS patients with esophageal symptoms and may contribute to the persistence of symptoms despite appropriate therapy of esophageal opportunistic infections.

Clostridium difficile-associated diarrhea in patients with HIV positivity and AIDS: a prospective controlled study

OBJECTIVE

To compare the clinical manifestations and therapeutic responses of Clostridium difficile infection in HIV-infected and noninfected individuals.

METHODS

Patients were identified for this study if they had C. difficile toxin in the stool. The patients were then followed prospectively by the investigators. All patients were treated with a standard regimen, and clinical and laboratory findings were recorded. Persistence and resolution or recurrence of symptoms and complications were recorded.

RESULTS

A total of 87 patients were studied, of which 12 were HIV positive, 20 had AIDS, and 55 had no known HIV infection. The AIDS group was younger and had a lower total leukocyte count than the controls. There were no statistically significant differences in temperature, leukocytosis, clinical symptoms, therapeutic response, or recurrence or persistent of symptoms.

CONCLUSIONS

Despite the immunosuppression of HIV infection, C. difficile infection behaves no differently in HIV/AIDS patients than it does in controls.

Endoscopy in the age of HIV: a study of current practices and attitudes

Gastroenterologists are frequently asked to perform a variety of endoscopic procedures in patients with AIDS. A study published 6 years ago concluded that costly and inefficient practices resulted from anxiety about transmitting human immunodeficiency virus (HIV) to endoscopic personnel. We re-examined, by means of a questionnaire mailed to 200 program directors in gastroenterology, the perceived risk of acquiring HIV infection via endoscopy. Although the perception of risk had not changed, the level of concern was relatively low and endoscopic personnel were less reluctant than previously to be involved with such patients. Notwithstanding, protective garments were used two to seven times more often when the patient was known to be HIV-positive.

Intestinal permeability in patients infected with the human immunodeficiency virus

OBJECTIVE

The etiology of acquired immunodeficiency syndrome (AIDS) enteropathy is unknown. This condition has been associated with malabsorption and villous atrophy. Other disorders with similar findings, including celiac disease, are characterized by altered intestinal permeability. Our objective was to confirm (or reject) our hypothesis that processes that cause increased permeability may occur in patients with AIDS, and thus be a cause of idiopathic diarrhea.

METHODS

A lactulose-mannitol differential intestinal permeability test was performed in healthy controls, asymptomatic human immunodeficiency virus (HIV)-positive patients, and AIDS patients with and without diarrhea.

RESULTS

Asymptomatic HIV-positive patients lactulose and mannitol recoveries were no different than healthy control patients. AIDS patients without diarrhea had lactulose recovery similar to healthy controls and decreased mannitol recoveries; their mean lactulose:mannitol ratio was no different from that of controls, and less than that of AIDS patients with diarrhea. AIDS patients with diarrhea had increased lactulose recovery and decreased mannitol recovery; their mean lactulose:mannitol ratio was significantly greater than the ratios in all the other groups.

CONCLUSIONS

Patients with AIDS and diarrhea have altered intestinal permeability. The decreased absorption of mannitol suggests that the functional absorptive surface of the intestine decreases as HIV disease progresses.