Appendectomy and Clostridium difficile colitis: Relationships revealed by clinical observations and immunology

Beyond a vestigial organ: effects of the appendix on gut microbiome and colorectal cancer

The role of appendectomy in the pathogenesis of colorectal cancer (CRC) is a recent topic of contention. Given that appendectomy remains one of the most commonly performed operations and a first-line management strategy of acute appendicitis, it is inherently crucial to elucidate the association between prior appendectomy and subsequent development of CRC, as there may be long-term health repercussions. In this review, we summarize the data behind the relationship of CRC in post-appendectomy patients, discuss the role of the microbiome in relation to appendectomy and CRC pathogenesis, and provide an appraisal of our current understanding of the function of the appendix. We seek to piece together the current landscape surrounding the microbiome and immunological changes in the colon post-appendectomy and suggest a direction for future research involving molecular, transcriptomic, and immunologic analysis to complement our current understanding of the alterations in gut microbiome.

Delivery of Fecal Material to Terminal Ileum Is Associated with Long-Term Success of Fecal Microbiota Transplantation

BACKGROUND

Fecal microbiota transplantation (FMT) is a highly effective treatment for recurrent Clostridioides difficile infection (CDI). However, 10-20% of patients still fail to recover following FMT. There is a need to understand why these failures occur and if there are modifiable factors that can be addressed by clinicians performing FMT.

AIMS

We sought to identify factors related to the FMT procedure itself which could impact FMT outcomes. We also aimed to identify patient demographics which might be associated with FMT outcomes and whether any factors were associated with early FMT failure compared to late CDI recurrence.

METHODS

We performed a retrospective multicenter cohort analysis of FMT procedures between October 2005 and November 2020. We collected data on patient demographics, details of the FMT procedure, and procedure outcomes. Using univariate and multivariate regression, we evaluated whether these factors were associated with long-term FMT success, early FMT failure (less than 60 days following procedure), or late CDI recurrence (more than 60 days following procedure).

RESULTS

Long-term success of FMT was strongly correlated with any delivery of stool to the terminal ileum (Odds Ratio [OR] 4.83, 95% confidence interval [CI] 1.359-17.167) and underlying neurologic disease (OR 8.012, 95% CI 1.041-61.684). Lower bowel prep quality was significantly associated with both early FMT failure (p = 0.034) and late CDI recurrence (p = 0.050).

CONCLUSIONS

Delivery of stool to the terminal ileum is significantly associated with long-term success following FMT. This is a relatively safe practice which could easily be incorporated into the standard of care for colonoscopic FMT.

Fecal microbiota transplantation as potential first-line treatment for patients with Clostridioides difficile infection and prior appendectomy

Clostridioides difficile infection (CDI) is a global health problem. The association of appendectomy on the severity and prognosis of CDI has been reported in many literatures, but there are still contradictions. In a retrospective study entitled “Patients with Closterium diffuse infection and prior appendectomy may be prone to word outcomes” published in World J Gastrointest Surg 2021, the author found that prior appendectomy affects the severity of CDI. Appendectomy may be a risk factor for increasing the severity of CDI. Therefore, it is necessary to seek alternative treatment for patients with prior appendectomy when they are more likely to have severe or fulminant CDI.

The Gut Microbiota and Inflammatory Factors in Pediatric Appendicitis

Background. The study analyzed gut microflora’s composition and investigated the associations between the associations between gut dysbiosis and inflammatory indicators in pediatric patients with acute appendicitis. Methods. High-throughput sequencing and bioinformatics analysis were used to investigate the composition and diversity of gut microflora in 20 pediatric patients with acute appendicitis and 11 healthy children. Endpoints measured were operational taxonomic units (OTU) of gut microflora. The OTU and its abundance analysis, sample diversity analysis, principal component analysis of samples, differential analysis, and analysis of biomarkers were performed. Results. Overall fecal microbial richness and diversity were similar in patients and controls. Yet richness within the group of Bilophila, Eggerthella, Clostridium, Parvimonas, Megasphaera, Atopobium, Phascolarctobacterium, Adlercreutzia, Barnesiella, Klebsiella, Enterococcus, and Prevotella genera was higher in patients. Adlercreutzia was significantly positively correlated with IL-10, while the three other genera, comprising Klebsiella, Adlercreutzia, and Prevotella, were positively correlated with B cells level. Conclusion. Gut microbiome components are significantly different in pediatric patients with acute appendicitis and healthy children. The differential abundance of some genera is correlated with the production of inflammatory markers in appendicitis.

Incidence of Early and Late-Onset Clostridioides difficile Infection following Appendectomy Compared to Other Common Abdominal Surgical Procedures

Introduction. Clostridioides difficile associated diarrhea (CDAD) is a major public health issue. The appendix may function as a reservoir for the intestinal microbiome, which may repopulate the intestine following enteric infections including CDAD. Patients/Methods. This retrospective cohort study includes a total of 12,039 patients undergoing appendectomy, hemicolectomy, and cholecystectomy at a single center between 1992 and 2011 who were diagnosed with early and late-onset CDAD and were followed for a minimum of two years. Results. Cumulative CDAD rates were 2.3% after appendectomy, 6.4% after left and 6.8% after right hemicolectomy, and 4% after cholecystectomy with a median onset of 76 (range 1–6011) days after the procedure. Median time to CDAD onset was 76 days after appendectomy, 23 days after left, 54 days after right hemicolectomy, and 122 days after cholecystectomy ( $p<0.05$ ). Late-onset CDAD (>1 year) was significantly more common following appendectomy (37%) and cholecystectomy (39%) than after left (17%) and right (21%) hemicolectomy. Significant differences in age, gender, complication rate, and length of hospitalization between the four groups need to be considered when interpreting the results. Conclusion. The incidence of CDAD after various abdominal surgeries ranged between 2% and 7% in this study. Whereas, hemicolectomy patients had predominantly early onset CDAD, and appendectomy and cholecystectomy may increase the risk for late-onset CDAD. Appendectomy per se does not seem to increase the risk for late-onset CDAD.

Children with appendectomy have increased risk of future sepsis: Real-world data in Taiwan

BACKGROUND

Appendectomy is one of the most commonly performed surgeries worldwide. Sepsis is a major aetiology of morbidity and mortality in children. Our preliminary research revealed a positive correlation amongst appendectomy and future risk of sepsis in adults. However, to date, the relationship between appendectomy and future risk of sepsis in children remains unknown. The aim of this research was to investigate the relationship between appendectomy and the hazard of future sepsis in children.

METHODS

We applied a nationwide population-based cohort to assess whether children who received appendectomy were at increased risk of subsequent sepsis. Overall, 57 261 subjects aged below 18 undergoing appendectomy as appendectomy group and 57 261 matched controls were identified as a non-appendectomy group from the National Health Insurance Research Database in Taiwan. We use propensity score analysis to match the age, sex, urbanisation level and parental occupation at the ratio to 1:1. Multiple Cox regression and stratified analyses were used to appraise the adjusted hazard ratio (aHR) for developing sepsis in children.

RESULTS

Children who received appendectomy had a 2.38 times higher risk (aHR: 2.38; 95% confidence interval [CI] = 1.98, 2.87) of developing sepsis than those who did not, and the risk was higher in all age groups (aHR: 2.98, 95% CI = 1.84, 4.83; aHR: 2.45, 95% CI = 1.08, 2.05; aHR: 2.18, 95% CI = 1.70, 2.80 in children aged <6, 7-12 and 13-18 years, respectively). Patients with <1-year follow-up showed a 4.53-fold risk of sepsis in the appendectomy cohort (aHR: 4.53, 95% CI = 2.80, 7.35). Patients with 1-4 and ≥5 years' follow-up showed a 2.19- and 1.94-times risk of sepsis (aHR: 2.19, 95% CI = 1.61, 2.97; aHR: 1.94, 95% CI = 1.48, 2.56 in 1-4 and >5 years, respectively).

CONCLUSION

Appendectomy was correlative to a 2.38-fold increased future sepsis risk in children, and the risk in all age groups was higher. More studies to interpret the possible biological mechanisms of the associations amongst sepsis and appendectomy are warranted.

Is endoscopic retrograde appendicitis therapy a better modality for acute uncomplicated appendicitis? A systematic review and meta-analysis

BACKGROUND

Previous studies had shown endoscopic retrograde appendicitis therapy (ERAT) is an effective treatment for acute appendicitis. However, different studies reported conflicting outcomes regarding the effectiveness of ERAT in comparison with laparoscopic appendectomy (LA).

AIM

To compare the effectiveness of ERAT with LA.

METHODS

Randomized controlled trials (RCTs) and retrospective studies of ERAT for acute uncomplicated appendicitis were searched in PubMed, Cochrane Library, Web of Science, Embase database, China National Knowledge Infrastructure (CNKI), the WanFang Database, and Chinese Scientific Journals Database (VIP) from the establishment date to March 1 2021. Heterogeneity was assessed using the I-squared statistic. Pooled odds ratios (OR), weighted mean difference (WMD), and standard mean difference (SMD), with 95% confidence intervals (CI) were calculated through either fixed-effects or random-effects model. Sensitivity analysis was also performed. Publication bias was tested by Egger's test, and Begg's test. The quality of included RCT were evaluated by the Jadad scale, while Newcastle-Ottawa scale is adopted for assessing the methodological quality of case-control studies. All statistical analysis was performed using Stata 15.1 statistical software. All statistical analysis was performed using Stata 15.1 statistical software. This study is registered with PROSPERO, CRD42021243955.

RESULTS

After screening, 10 RCTs and 2 case-control studies were included in the current systematic review. Firstly, the length of hospitalizations [WMD = -1.15, 95%CI: -1.99, -0.31; P = 0.007] was shorter than LA group. Secondly, the level of post-operative CRP [WMD = -10.06, 95%CI: (-17.39, -2.73); P = 0.007], TNF-α [WMD = -7.70, 95%CI: (-8.47, -6.93); P < 0.001], and IL-6 Levels [WMD = -9.78, 95%CI: (-10.69, -8.88); P < 0.001; P < 0.001] in ERAT group was significantly lower than LA group. Thirdly, ERAT group had a lower incidence of intestinal obstruction than LA group. [OR = 0.19, 95%CI: (0.05, 0.79); P = 0.020]. Moreover, the quality of 10 RCTs were low with 0-3 Jadad scores, while the methodological quality of two case-control studies were fair with a score of 2 (each).

CONCLUSION

Compared with LA, ERAT reduces operation time, the level of postoperative inflammation, and results in fewer complications and shorter recovery time, with preserving the appendix and its immune and biological functions.

Wild black bears harbor simple gut microbial communities with little difference between the jejunum and colon

The gut microbiome (GMB), comprising the commensal microbial communities located in the gastrointestinal tract, has co-evolved in mammals to perform countless micro-ecosystem services to facilitate physiological functions. Because of the complex inter-relationship between mammals and their gut microbes, the number of studies addressing the role of the GMB on mammalian health is almost exclusively limited to human studies and model organisms. Furthermore, much of our knowledge of wildlife-GMB relationships is based on studies of colonic GMB communities derived from the feces of captive specimens, leaving our understanding of the GMB in wildlife limited. To better understand wildlife-GMB relationships, we engaged hunters as citizen scientists to collect biological samples from legally harvested black bears (Ursus americanus) and used 16S rRNA gene amplicon sequencing to characterize wild black bear GMB communities in the colon and jejunum, two functionally distinct regions of the gastrointestinal tract. We determined that the jejunum and colon of black bears do not harbor significantly different GMB communities: both gastrointestinal sites were dominated by Firmicutes and Proteobacteria. However, a number of bacteria were differentially enriched in each site, with the colon harboring twice as many enriched taxa, primarily from closely related lineages.

The modified endoscopic retrograde appendicitis therapy versus antibiotic therapy alone for acute uncomplicated appendicitis in children

BACKGROUND

Endoscopic retrograde appendicitis therapy (ERAT) is an emerging endoscopic treatment modality for acute uncomplicated appendicitis (AUA) supported by several case series. However, to date, systematic studies have not been conducted in children and the prospective comparative data are lacking. Moreover, due to a concern for future malignancy risk in children from ionizing radiation, we used contrast-enhanced ultrasound (CEUS) instead of endoscopic retrograde appendiceal radiography (ERAR). Therefore, we conducted a prospective, randomized control clinical trial to compare the modified ERAT (mERAT) to antibiotic therapy in children with AUA. The aim of this study was to evaluate the safety and feasibility and of mERAT in the treatment of hospitalized children with AUA.

METHODS

Children with AUA, confirmed by ultrasonography and or abdominal computed tomography, were consecutively enrolled from October 2018 to February, 2020. They were randomly assigned to receive mERAT or routine antibiotic treatment. Patients were followed until May, 2020. Th primary outcome variable was the duration of relief of the abdominal pain after treatment. We collected patient's demographics, ultrasonic imaging findings, colonoscopy findings, and treatment outcomes of the mERAT and adverse even associated with mERAT.

RESULTS

A total of 83 children were enrolled. 36 were randomized to mERAT and 47 to antibiotics treatment. All children in the mERAT group had endoscopic confirmed acute uncomplicated appendicitis, and there were no significant complications. However, 9 of patients in antibiotic group were poor responsive to treatment and switched to mERAT. The overall success rate of treatment with mERAT (100%) was significantly higher than that of antibiotics (80.9%) (P = 0.004). The median time to discharge was significantly shorter in mERAT group than in antibiotics treatment group [6.0 ± 1.76 days] (P = 0.004).

CONCLUSIONS

mERAT provide a new alternative therapeutic option for childhood with AUA, especially for families who are reluctant to undergo an appendectomy.

The Impact of Appendectomy in Clostridium difficile Infection and Length of Hospital Stay

Introduction

We aim to investigate Clostridium difficile infection (CDI) recurrence, severity, complications, and length of hospital stay in patients with and without prior history of appendectomy who were admitted to the hospital with CDI.

Method

We analyzed retrospective data for 862 patients, 18 years and older, with C. difficile inpatients diagnosed between January 1, 2017 and December 31, 2018 and sorted into two groups, with or without prior appendicectomy, to look for outcomes such as recurrence, hospital stay, complications, and related death in each group and use statistical analysis for comparison.

Result

There were 862 patients admitted with CDI, of which 122 (14.2%) had a prior history of appendectomy and 740 (85.8%) did not. Patients with an appendectomy prior were older (median age of 75 vs. 69, p = 0.0033) and had a higher proportion of females (68.9% vs. 53.6%, p = 0.0017).

C. difficile recurrence in prior appendicectomy group vs. no appendectomy group was 12.3% and 9.3%, respectively, but no statistical difference was noted (p = 0.28). Also, there was no statistical difference in complications like ileus, colectomy, and mortality related to CDI in both groups. However, patients with appendectomies had significantly shorter hospital stays during C. difficile admission compared to patients without appendectomies (median of six days vs. seven days, p = 0.0014).

Conclusion

Our study shows that there is no statistical difference in the recurrence, severity, and complications of CDI in the presence or absence of the appendix but remarkably noted that people with prior appendicectomy had a shorter hospital stay.

Appendectomy as a Potential Predisposing Factor for the Development of Recurrent and Fulminant Clostridium Difficile

This literature review assesses how the vermiform appendix has been considered a vestigial organ by many, but over the years, new research has allowed us to reconsider its potential purpose. Studies have indicated that the appendix plays an evident role in immune response and harbors a biofilm that may remain unaffected by gastrointestinal infections, such as infection with Clostridium difficile. Our research analyzes the prominent gut-associated lymphoid tissue (GALT) as a mechanism of defence in infection, as well as the robust biofilm that could aid in the reinoculation of beneficial bacteria within the colon. Furthermore, we wanted to determine if patients who have undergone a prior appendectomy, leading to decreased GALT and a lack of a bacterial reservoir, were predisposed to the development of Clostridium difficile, with particular emphasis in the recurrence and development of fulminant Clostridium difficile infections. Although research continues to be conflicting, there appears to be some connection between these variables, but prospective studies are needed in order to say for certain that there is a link.

Improvement of Alcohol-Poisoning Symptoms in Mice by the Oral Administration of Live Lactobacillus plantarum SN13T Cells

A clinical study carried out previously by our group has demonstrated that yogurt manufactured with a plant-derived lactic acid bacterium, Lactobacillus plantarum SN13T, significantly reduces the γ-glutamyl transpeptidase (γ-GTP) level as a liver-function parameter. In the present study, we show that with the oral administration of live SN13T cells, alcohol-poisoning symptoms in mice are improved, and the condition does not become fatal. However, prior to the simultaneous administration with ethanol, when the cells were heat-killed or sonicated, the improvement was not observed, and almost all of the mice died. In addition, the dysbiosis of the intestinal microbiota observed in the mice administered with ethanol was restored by simultaneous administration with live SN13T cells. Furthermore, by analyzing the metabolites detected in contents from the mouse cecum, it was demonstrated that the increase in nonvolatile putrefactive amines observed in the ethanol-administration group was reduced by simultaneous administration with live SN13T cells. Judging from these results, the lactic acid bacterial cells capable of reaching the living bowels prevent ethanol-induced poisoning and restore the intestinal microbiota.

Prior Appendectomy and the Onset and Course of Crohn's Disease in Chinese Patients

Background and Aim

The relationship between prior appendectomy and Crohn's disease (CD) has previously revealed conflicting findings. The present study investigates the relationship between prior appendectomy and CD development in Chinese patients.

Methods

A retrospective case-control study was performed to compare prior appendectomy rate between CD patients and age- and gender-matched controls at two Chinese hospitals. The clinical course of CD was determined in patients who underwent and did not undergo appendectomies before CD diagnosis.

Results

A total of 617 CD patients and 617 controls were included. The appendectomy rate before CD diagnosis in patients was higher, when compared to controls (6.65% versus 3.73%, P = 0.033). Appendectomy was a risk factor for the onset of CD independent of smoking in the multivariate analysis (OR: 1.878; 95% CI: 1.111–3.174; P = 0.019). Appendectomies were performed closer to the date of CD diagnosis in the trend test (P = 0.039). The rate of appendectomy within one year or 1-5 years before CD diagnosis was higher in patients when compared to that in controls (0.97% versus 0%, P = 0.031; 1.13% versus 0.32%, P = 0.180). However, the rate of appendectomy over five years before CD diagnosis was close to controls (4.54% versus 3.40%, P = 0.392). No significant differences in disease location, behavior, medication, and intestinal resection between appendectomy and nonappendectomy CD patients were found, even in the subgroup analysis by age of appendectomy.

Conclusion

Prior appendectomy is a risk factor for the onset of CD. However, the appendectomy rate only increased for a short duration before CD diagnosis, likely reflecting a diagnostic bias. Prior appendectomy did not influence the features or course of CD.

Methods of conservative antibiotic treatment of acute uncomplicated appendicitis: A systematic review

BACKGROUND

Meta-analyses and a recent guideline acknowledge that conservative management of uncomplicated appendicitis with antibiotics can be successful for patients who wish to avoid surgery. However, guidance as to specific management does not exist.

METHODS

PUBMED and EMBASE search of trials describing methods of conservative treatment was conducted according to Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines.

RESULTS

Thirty-four studies involving 2,944 antibiotic-treated participants were identified. The greatest experience with conservative treatment is in persons 5 to 50 years of age. In most trials, imaging was used to confirm localized appendicitis without evidence of abscess, phlegmon, or tumor. Antibiotics regimens were generally consistent with intra-abdominal infection treatment guidelines and used for a total of 7 to 10 days. Approaches ranged from 3-day hospitalization on parenteral agents to same-day hospital or ED discharge of stable patients with outpatient oral antibiotics. Minimum time allowed before response was evaluated varied from 8 to 72 hours. Although pain was a common criterion for nonresponse and appendectomy, analgesic regimens were poorly described. Trials differed in use of other response indicators, that is, white blood cell count, C-reactive protein, and reimaging. Diet ranged from restriction for 48 hours to as tolerated. Initial response rates were generally greater than 90% and most participants improved by 24 to 48 hours, with no related severe sepsis or deaths. In most studies, appendectomy was recommended for recurrence; however, in several, patients had antibiotic retreatment with success.

CONCLUSION

While further investigation of conservative treatment is ongoing, patients considering this approach should be advised and managed according to study methods and related guidelines to promote informed shared decision-making and optimize their chance of similar outcomes as described in published trials. Future studies that address biases associated with enrollment and response evaluation, employ best-practice pain control and antibiotic selection, better define cancer risk, and explore longer time thresholds for response, minimized diet restriction and hospital stays, and antibiotic re-treatment will further our understanding of the potential effectiveness of conservative management.

LEVEL OF EVIDENCE

Systematic review, level II.

2019 update of the WSES guidelines for management of Clostridioides (Clostridium) difficile infection in surgical patients

In the last three decades, Clostridium difficile infection (CDI) has increased in incidence and severity in many countries worldwide. The increase in CDI incidence has been particularly apparent among surgical patients. Therefore, prevention of CDI and optimization of management in the surgical patient are paramount. An international multidisciplinary panel of experts from the World Society of Emergency Surgery (WSES) updated its guidelines for management of CDI in surgical patients according to the most recent available literature. The update includes recent changes introduced in the management of this infection.

2019 update of the WSES guidelines for management of Clostridioides (Clostridium) difficile infection in surgical patients

In the last three decades, Clostridium difficile infection (CDI) has increased in incidence and severity in many countries worldwide. The increase in CDI incidence has been particularly apparent among surgical patients. Therefore, prevention of CDI and optimization of management in the surgical patient are paramount. An international multidisciplinary panel of experts from the World Society of Emergency Surgery (WSES) updated its guidelines for management of CDI in surgical patients according to the most recent available literature. The update includes recent changes introduced in the management of this infection.

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.

Effects of Appendectomy on the Onset and Course of Ulcerative Colitis in Chinese Patients

Background

Previous epidemiological studies have suggested that appendectomy may be a protective factor against the development of ulcerative colitis (UC). However, the results of these studies were inconsistent, with rare studies in Chinese populations.

Aim

This study examined the associations between appendectomy performed before UC diagnosis and the occurrence and clinical course of UC in Chinese patients.

Methods

A case control study was conducted to compare the rate of appendectomy between UC patients and controls matched for age and sex at two Chinese hospitals. Clinical course of UC was compared between UC patients who underwent appendectomies before UC diagnosis and who did not.

Results

402 UC patients and 402 controls were included. The percentage of appendectomy performed before UC diagnosis in UC patients did not differ significantly from controls (2.74% vs 3.98%, P = 0.442). Subgroup analysis on the basis of localization of UC patients did not find significant difference from controls. The extent of disease involvement in UC patients who underwent appendectomy was smaller than patients who did not (P = 0.009). Appendectomy was found to be significantly related to the location of the disease independent of smoking status in multivariate analysis (P < 0.001). Appendectomy did not influence severity of disease and need for immunosuppressive treatment or colectomy.

Conclusion

We did not find a significant negative association between appendectomy and the UC occurrence in Chinese patients. Appendectomy performed before UC diagnosis may reduce the extent of UC involvement.

Impact of age at appendectomy on development of type 2 diabetes: A population-based cohort study

Aim

Diabetes is a complex metabolic disease characterized by chronic low-grade inflammation in which genetic and environmental factors are involved. Growing evidence implicates that alterations of the gut microbiota potentially contribute to the emergence of metabolic diseases. The human appendix has more recently been recognized as a microbial reservoir for repopulating the gastrointestinal tract and an important part of the immune system. Thus, appendectomy may influence microbial ecology and immune function. This study investigated the association between appendectomy and type 2 diabetes risk.

Methods

We analyzed a cohort of 10954 patients who underwent appendectomy between 1998 and 2013 based on the Taiwan National Health Insurance Program database. A comparison cohort of 43815 persons without appendectomy was selected randomly and matched by sex, age, comorbidities, and index year. To ensure reliability of the results, a sensitivity analysis using a propensity score–matched study was performed. We observed the subsequent development of type 2 diabetes in both cohorts.

Results

Although the overall incidence of type 2 diabetes in the appendectomy patients was 7.9% higher than that in the non-appendectomy patients, it was not statistically significant (95% confidence interval [CI], 0.997–1.168) after the adjustment of confounding factors. Multivariate regression analysis revealed that the adjusted hazard ratio (HR) of type 2 diabetes was 1.347 for appendectomy patients < 30 years of age (95% CI, 1.009–1.798) compared to non-appendectomy patients. The incidence of type 2 diabetes was higher within 3 years of post-appendectomy follow-up than for non-appendectomy patients (HR, 2.017; 95% CI, 1.07–3.802). Age impacted the association between appendectomy and type 2 diabetes risk (P_interaction = 0.002); in contrast, sex did not affect the association between appendectomy and type 2 diabetes risk (P_interaction = 0.88).

Conclusions

Our study results suggest that appendectomy increases type 2 diabetes risk, particularly when performed prior to middle age.

Women who had appendectomy have increased risk of systemic lupus erythematosus: a nationwide cohort study

The appendix is involved in immune function, and an appendectomy may alter the immune system. Studies evaluating the relationship between previous appendectomy and the risk of systemic lupus erythematosus (SLE) are lacking. This nationwide cohort study investigated the incidence and risk of SLE in patients who underwent appendectomy. Patients aged > 20 years who received appendectomy from 2000 to 2011 were identified from the National Health Insurance Research Database and assigned to the appendectomy cohort. Patients without appendectomy were randomly selected from the NHIRD and assigned to the control cohort; they were frequency matched to each study patient at a 4:1 ratio by sex, age, and index year. All patients were followed until SLE diagnosis, withdrawal from the National Health Insurance program, or the end of 2011. We used Cox models to estimate the hazard ratio (HR) and 95% confidence interval (CI) to compare the risk of SLE between the appendectomy and control cohorts. From 23.74 million people in the cohort, 80,582 patients undergoing appendectomy and 323,850 patients without appendectomy were followed for 723,438 and 2,931,737 person-years, respectively. The appendectomy cohort had a 2.04-fold higher risk of SLE than the control cohort (adjusted HR = 2.04, 95% CI = 1.52-2.76). Women aged ≤ 49 years who underwent appendectomy had a 2.27-fold higher risk of SLE than the corresponding controls (adjusted HR = 2.27, 95% CI = 1.62-3.19). Women aged ≤ 49 years who underwent appendectomy have a significantly higher risk of SLE.

Increased chronic kidney disease development and progression in diabetic patients after appendectomy: a population-based cohort study

Background

The vermiform appendix serves as a "safe house" for maintaining normal gut bacteria and appendectomy may impair the intestinal microbiota. Appendectomy is expected to profoundly alter the immune system and modulate the pathogenic inflammatory immune responses of the gut. Recent studies have shown that a dysbiotic gut increases the risk of cardiovascular disease and chronic kidney disease (CKD). Therefore, we hypothesized that appendectomy would increase the risk of CKD.

Methods

This nationwide, population-based, propensity-score-matched cohort study included 10,383 patients who underwent appendectomy and 41,532 propensity-score-matched controls. Data were collected by the National Health Insurance Research Database of Taiwan from 2000 to 2013. We examined the associations between appendectomy and CKD and end-stage renal disease (ESRD). The major outcome was a new diagnosis of CKD based on an outpatient diagnosis made at least three times or hospital discharge diagnosis made once during the follow-up period. ESRD was defined as undergoing dialysis therapy for at least 90 days, as in previous studies.

Results

The incidence rates of CKD and ESRD were higher in the appendectomy group than in the control cohort (CKD: 6.52 vs. 5.93 per 1,000 person-years, respectively; ESRD: 0.49 vs. 0.31 per 1,000 person-years, respectively). Appendectomy patients also had a higher risk of developing CKD (adjusted hazard ratio [aHR] 1.13; 95% CI [1.01-1.26]; P = 0.037) and ESRD (aHR 1.59; 95% CI [1.06-2.37]; P = 0.024) than control group patients. Subgroup analysis showed that appendectomy patients with concomitant diabetes mellitus (aHR 2.08; P = 0.004) were at higher risk of incident ESRD than those without diabetes mellitus. The interaction effects of appendectomy and diabetes mellitus were significant for ESRD risk (P = 0.022); no interaction effect was found for CKD risk (P = 0.555).

Conclusions

Appendectomy increases the risk of developing CKD and ESRD, especially in diabetic patients. Physicians should pay close attention to renal function prognosis in appendectomy patients.

Appendectomy as a Risk Factor for Bacteremic Biliary Tract Infection Caused by Antibiotic-Resistant Pathogens

Background/Aims

Recent evidence has suggested that appendix plays a pivotal role in the development and preservation of intestinal immune system. The aim of this study is to examine whether prior appendectomy is associated with an increased risk for the development of antibiotic-resistant bacteria in bacteremia from biliary tract infection (BTI).

Methods

Charts from 174 consecutive cases of bacteremia derived from BTI were retrospectively reviewed. Using multivariate analysis, independent risk factors for development of antibiotic-resistant bacteria were identified among the clinical parameters, including a history of appendectomy.

Results

In total, 221 bacteria strains were identified from 174 BTI events. Of those, 42 antibiotic-resistant bacteria were identified in 34 patients. Multivariate analysis revealed that prior appendectomy (Odds ratio (OR), 3.02; 95% confidence interval (CI), 1.15–7.87; p = 0.026), antibiotic use within the preceding three months (OR, 3.06; 95% CI, 1.26–7.64; p = 0.013), and bilioenteric anastomosis or sphincterotomy (OR, 3.77; 95% CI, 1.51–9.66; p = 0.0046) were independent risk factors for antibiotic-resistant bacteria.

Conclusions

Prior appendectomy was an independent risk factor for the development of antibiotic-resistant bacteria in bacteremia from BTI.

Pediatric appendicitis: state of the art review

Appendicitis is a common cause of abdominal pain in children. The diagnosis and treatment of the disease have undergone major changes in the past two decades, primarily as a result of the application of an evidence-based approach. Data from several randomized controlled trials, large database studies, and meta-analyses have fundamentally affected patient care. The best diagnostic approach is a standardized clinical pathway with a scoring system and selective imaging. Non-operative management of simple appendicitis is a reasonable option in selected cases, with the caveat that data in children remain limited. A minimally invasive (laparoscopic) appendectomy is the current standard in US and European children's hospitals. This article reviews the current 'state of the art' in the evaluation and management of pediatric appendicitis.

The Tragedy of the Unexamined Cat: Why K-12 and University Education Are Still in the Dark Ages and How Citizen Science Allows for a Renaissance

At the end of the dark ages, anatomy was taught as though everything that could be known was known. Scholars learned about what had been discovered rather than how to make discoveries. This was true even though the body (and the rest of biology) was very poorly understood. The renaissance eventually brought a revolution in how scholars (and graduate students) were trained and worked. This revolution never occurred in K-12 or university education such that we now teach young students in much the way that scholars were taught in the dark ages, we teach them what is already known rather than the process of knowing. Citizen science offers a way to change K-12 and university education and, in doing so, complete the renaissance. Here we offer an example of such an approach and call for change in the way students are taught science, change that is more possible than it has ever been and is, nonetheless, five hundred years delayed.

The Link between the Appendix and Ulcerative Colitis: Clinical Relevance and Potential Immunological Mechanisms

The human appendix has long been considered as a vestigial organ, an organ that has lost its function during evolution. In recent years, however, reports have emerged that link the appendix to numerous immunological functions in humans. Evidence has been presented for an important role of the appendix in maintaining intestinal health. This theory suggests that the appendix may be a reservoir or 'safe house' from which the commensal gut flora can rapidly be reestablished if it is eradicated from the colon. However, the appendix may also have a role in the development of inflammatory bowel disease (IBD). Several large epidemiological cohort studies have demonstrated the preventive effect of appendectomy on the development of ulcerative colitis, a finding that has been confirmed in murine colitis models. In addition, current studies are examining the possible therapeutic effect of an appendectomy to modulate disease course in patients with ulcerative colitis. This literature review assesses the current knowledge about the clinical and immunological aspects of the vermiform appendix in IBD and suggests that the idea of the appendix as a vestigial remnant should be discarded.

WSES guidelines for management of Clostridium difficile infection in surgical patients

In the last two decades there have been dramatic changes in the epidemiology of Clostridium difficile infection (CDI), with increases in incidence and severity of disease in many countries worldwide. The incidence of CDI has also increased in surgical patients. Optimization of management of C difficile, has therefore become increasingly urgent. An international multidisciplinary panel of experts prepared evidenced-based World Society of Emergency Surgery (WSES) guidelines for management of CDI in surgical patients.

The murine appendiceal microbiome is altered in spontaneous colitis and its pathological progression

BACKGROUND

Inflammatory bowel disease (comprising ulcerative colitis and Crohn's disease) is a multifactorial disease that is extensively associated with stool microbiome changes (dysbiosis). Appendicitis and appendectomy limits subsequent colitis, clinically, and in animal models. We wanted to examine how the appendiceal and stool microbiome fared in our spontaneous colitic Winnie (Muc2(-/-)) mice model.

METHODS

Two C57BL/6 and 10 Winnie mice at ages 12 and 15 weeks were euthanized for stool and caecal patch samples. DNA was extracted using the QIAamp DNA Stool Mini Kit then the V1-V3 hypervariable region of the 16S rRNA gene was sequenced using the Roche/454 GS FLX + pyrosequencing instrument. A Galaxy metagenomic pipeline was used to define phyla and families at sequence similarity threshold of ≥ 80%.

RESULTS

Bacteriodetes was decreased in 15-week Winnie mice appendices compared to corresponding stool samples (P < 0.01). Proteobacteria was increased in appendices of Winnie mice compared to corresponding stool samples (P < 0.05). The Bacteroidetes family Rikenellaceae could be identified only in 15-week-old Winnie mice appendices. A higher quantity of Acetobacteraceae (Proteobacteria phylum) was present in 15-week Winnie mice when compared to 12-week Winnie mice (P < 0.01). Helicobacteraceae (Proteobacteria phylum), which is prominent in all Winnie mice, is absent in control mice.

CONCLUSIONS

The appendiceal dysbiosis observed in our Winnie mice is commensurate with, and adds to extant literature data. The presence of Helicobacteraceae (Proteobacteria) only in colitic Winnie mice (but not control mice) is consistent with reports of increased Helicobacter in IBD patients. Bacteroides (Bacteroidetes) decreases may be a reflection of reduced anti-inflammatory commensal species such as B. fragilis. Further research is warranted to expand and delineate the relationship between IBD and the appendix microbiome.

Appendicectomy and clostridium difficile infection: is there a link?

Clostridium difficile infection (CDI) is a gradually emerging healthcare problem in the western world, occurring predominantly from the de-arrangement of the gut microbiota and the widespread use of antibiotics. Recently, it has been proposed that the presence or absence of the appendix could be a factor influencing the occurrence and/or the severity of CDI. We performed a review of the literature, aiming to identify and interpret in an accumulative way the results of the published clinical studies which addressed the issue of a possible association between prior appendicectomy and the features of CDI. A total of five suitable studies were retrieved, which were all conducted retrospectively. Although the results were conflicting regarding the impact of prior appendicectomy in the occurrence and relapse of CDI, it appears that the presence or absence of the appendix is not associated with the clinical severity of CDI. Based on the current evidence and considering the effects of the widespread use of antibiotics in the clinical practice, it appears that an in situ appendix does not have a definitive impact on the development and severity of CDI. Further observational studies are warranted to clarify any potential association.