Role of obstruction in the pathogenesis of acute appendicitis

Routine colonoscopy with a surprise in the cecum: It's a giant appendicolith! A Case report and review of the literature

Giant appendicoliths (defined as appendiceal stones larger than 2 cm in size) are rare findings, with less than 20 well-documented reported cases. Appendicoliths, in general, are linked to an increased risk of appendicitis and associated complications. However, little information is available on the clinical impact of giant appendicoliths. We present a case of a giant appendicolith accidentally discovered during screening colonoscopy. With more than 4 cm, this appendicolith is one of the largest of the few reported so far. In contrast to all other cases of giant appendicoliths, the patient did not exhibit any symptoms. Additionally, we provide an overview of giant appendicolith cases, discussing their clinical features, diagnosis, and treatment.

Non-invasive diagnosis of bacterial and non-bacterial inflammations using a dual-enzyme-responsive fluorescent indicator

Bacterial infections, as the second leading cause of global death, are commonly treated with antibiotics. However, the improper use of antibiotics contributes to the development of bacterial resistance. Therefore, the accurate differentiation between bacterial and non-bacterial inflammations is of utmost importance in the judicious administration of clinical antibiotics and the prevention of bacterial resistance. However, as of now, no fluorescent probes have yet been designed for the relevant assessments. To this end, the present study reports the development of a novel fluorescence probe (CyQ) that exhibits dual-enzyme responsiveness. The designed probe demonstrated excellent sensitivity in detecting NTR and NAD(P)H, which served as critical indicators for bacterial and non-bacterial inflammations. The utilization of CyQ enabled the efficient detection of NTR and NAD(P)H in distinct channels, exhibiting impressive detection limits of 0.26 μg mL-1 for NTR and 5.54 μM for NAD(P)H, respectively. Experimental trials conducted on living cells demonstrated CyQ's ability to differentiate the variations in NTR and NAD(P)H levels between A. baumannii, S. aureus, E. faecium, and P. aeruginosa-infected as well as LPS-stimulated HUVEC cells. Furthermore, in vivo zebrafish experiments demonstrated the efficacy of CyQ in accurately discerning variations in NTR and NAD(P)H levels resulting from bacterial infection or LPS stimulation, thereby facilitating non-invasive detection of both bacterial and non-bacterial inflammations. The outstanding discriminatory ability of CyQ between bacterial and non-bacterial inflammation positions it as a promising clinical diagnostic tool for acute inflammations.

A comprehensive microbial analysis of pediatric patients with acute appendicitis

BACKGROUND

Pathogenesis of pediatric acute appendicitis (AA) is yet to be elucidated. Therefore, we performed a comprehensive microbial analysis of saliva, feces, and appendiceal lumen of AA patients using 16S ribosomal RNA (rRNA) gene amplicon sequencing to elucidate the pathogenesis of pediatric AA.

METHODS

This study included 33 AA patients and 17 healthy controls (HCs) aged <15 y. Among the AA patients, 18 had simple appendicitis, and 15 had complicated appendicitis. Salivary and fecal samples were obtained from both groups. The contents of the appendiceal lumen were collected from the AA group. All samples were analyzed using 16S rRNA gene amplicon sequencing.

RESULTS

The relative abundance of Fusobacterium was significantly higher in the saliva of AA patients as compared to that in HCs (P = 0.011). Bacteroides, Escherichia, Fusobacterium, Coprobacillus, and Flavonifractor were significantly increased in the feces of AA patients, as compared to that in HCs (P = 0.020, 0.010, 0.029, 0.031, and 0.002, respectively). In the appendiceal lumen, Bacteroides, Parvimonas, Fusobacterium, and Alloprevotella were the top bacterial genera with an average relative abundance >5% (16.0%, 9.1%, 7.9%, and 6.0%, respectively).

CONCLUSIONS

The relative abundance of Fusobacterium was high in the appendiceal lumen of pediatric AA patients. Moreover, the relative abundance of Fusobacterium was significantly higher in the saliva and feces of pediatric AA patients than in those of healthy children. These results suggest that ectopic colonization of oral Fusobacterium in the appendix might play an important role in the pathogenesis of pediatric AA.

Microbial Epidemiology of Acute and Perforated Appendicitis: A Post-Hoc Analysis of an EAST Multicenter Study

BACKGROUND

There are significant practice variations in antibiotic treatment for appendicitis, ranging from short-course narrow spectrum to long-course broad-spectrum. We sought to describe the modern microbial epidemiology of acute and perforated appendicitis in adults to help inform appropriate empiric coverage and support antibiotic stewardship initiatives.

METHODS

This is a post-hoc secondary analysis of the Multicenter Study of the Treatment of Appendicitis in America: Acute, Perforated, and Gangrenous (MUSTANG) which prospectively enrolled adult patients (age ≥ 18 years) diagnosed with appendicitis between January 2017 and June 2018 across 28 centers in the United States. We included all subjects with positive microbiologic cultures during primary or secondary (rescue after medical failure) appendectomy or percutaneous drainage. Culture yield was compared between low- and high-grade appendicitis as per the AAST classification.

RESULTS

A total of 3,471 patients were included: 230 (7%) had cultures performed, and 179/230 (78%) had positive results. Cultures were less likely to be positive in grade 1 compared to grades 3, 4, or 5 appendicitis with 2/18 (11%) vs 61/70 (87%) (p < .001). Only 1 subject had grade 2 appendicitis and culture results were negative. E. coli was the most common pathogen and cultured in 29 (46%) of primary appendectomy samples, 16 (50%) of secondary, and 44 (52%) of percutaneous drainage samples.

CONCLUSION

Culturing low-grade appendicitis is low yield. E. coli is the most commonly cultured microbe in acute and perforated appendicitis. This data helps inform empiric coverage for both antibiotics alone and as an adjunct to operative or percutaneous intervention.

Associations of hair cortisol concentrations with paediatric appendicitis

The pathogenesis of paediatric appendicitis is still an enigma. In recent years, it has become more evident that our inherent immunological responses affect the trajectory of the disease course. Long-term stress has an impact on our immune system; however, it is practically and ethically challenging to prospectively track blood measurements of cortisol-levels in asymptomatic children should an acute appendicitis episode develop. The aim of this case–control study was therefore to evaluate the effect of increased stress measured as historical imprints in hair (hair cortisol concentrations [HCC]), on the risk of developing appendicitis and complicated appendicitis. 51 children (aged < 15 years) with appendicitis (34 with complicated appendicitis), were compared to 86 healthy controls. HCC reflecting the activity of the HPA-axis 0–3 and 4–6 months prior to sampling was evaluated and compared between groups as well as between the two measurements of each study subject. In the univariate analysis with both cases and controls, an increase in HCC between the measurement timepoints was associated with a substantial increase in risk of appendicitis (OR 7.52 [95% CI 2.49–22.67], p = 0.001). This increased risk remained in the multivariate analysis after adjustment for age, sex and season (aOR OR 10.76 [95%CI 2.50–46.28], p  = 0.001). When comparing the cases of uncomplicated and complicated appendicitis through a multivariate analysis, adjusted for age and sex, the children with an increased HCC prior to appendicitis had a substantial and statistically significant increase in risk of complicated appendicitis (aOR 7.86 [95% CI 1.20–51.63], p = 0.03). Biological stress, measured as an increase in HCC, seems to be associated with an increased risk of paediatric appendicitis and a more complicated disease course.

The Impact of Pathological Criteria on Pediatric Negative Appendectomy Rate

INTRODUCTION

Negative appendectomy rate (NAR) is a quality metric used in the surgical management of appendicitis. The rates of negative appendectomy (NA) in children range anywhere from 1% to 40% in the literature. Many reports do not provide clear pathological definitions for either appendicitis or NA on which they base their calculation of NAR. We reviewed our experience with pediatric appendectomy and the pathological spectrum encompassed within our definition of a NA and examined how the pathologic definition impacts our hospital's NAR.

METHODS

A retrospective review from 2012 to 2016 in a single institution identified 1676 children that underwent appendectomy. Average age was 11.4 (2-18 years). Patient demographics, clinical outcomes and pathological findings were collected. At our institution, appendicitis is defined as the presence of transmural acute inflammation in the appendix and those patients without this finding have been considered to have had a negative appendectomy.

RESULTS

1435 patients underwent appendectomy for presumed appendicitis. The rate of pathologically diagnosed appendicitis was 91.1% (1307/1435) and as such, the NAR was 8.9% (128/1435). Review of the pathology of the NA cohort identified 67/128 (52.3%) patients with completely normal pathology. The remaining 61 patients displayed some sort of pathological abnormality including malignancy (n = 2), fecaliths (n = 9), pinworms (n = 3), granuloma (n = 2), fibrous obliteration (n = 4), isolated periappendiceal inflammation (n = 1), and acute inflammation confined to the mucosa (n = 40). Exclusion of these patients with abnormal pathology decreased the NAR to 4.6%. Patients with pathological abnormalities of the appendix other than transmural inflammation had a higher rate of 30-day readmission than patients with acute appendicitis (8.2% versus 4.5% p < 0.01).

CONCLUSION

Pediatric NAR is dependent upon the pathological definition of appendicitis and negative appendectomy. Institutional variation in definition may explain discrepancies in the literature. By example, including only those that show "the absence of inflammation or other appendiceal pathology" would decrease our NAR by 50%. This study calls into question the interpretation of interhospital NAR and the use of NAR as a quality metric in the management of appendicitis. Retrospective comparative study: Level III evidence.

Clinical differentiation of acute appendicitis and right colonic diverticulitis: A case-control study

BACKGROUND

Acute right colonic diverticulitis (ARCD) is an important differential diagnosis of acute appendicitis (AA) in Asian countries because of the unusually high prevalence of right colonic diverticula. Due to qualitative improvement and the high penetration rate of computed tomography (CT) scanning in Japan, differentiation of ARCD and AA mainly depends on this modality. But cost, limited availability, and concern for radiation exposure make CT scanning problematic. Differential findings of ARCD from AA are based on several small studies that used univariate comparisons from Korea and Taiwan. Previous studies on clinical and laboratory differences between AA and ARCD are limited.

AIM

To determine clinical differences between AA and ARCD for differentiation of these two diagnoses by creating a logistic regression model.

METHODS

We performed an exploratory single-center retrospective case-control study evaluating 369 Japanese patients (age ≥ 16 years), 236 (64.0%) with AA and 133 (36.0%) with ARCD, who were hospitalized between 2012 and 2016. Diagnoses were confirmed by CT images. We compared age, sex, onset-to-visit interval, epigastric/periumbilical pain, right lower quadrant (RLQ) pain, nausea/vomiting, diarrhea, anorexia, medical history, body temperature, blood pressure, heart rate, RLQ tenderness, peritoneal signs, leukocyte count, and levels of serum creatinine, serum C-reactive protein (CRP), and serum alanine aminotrans-ferase. We subsequently performed logistic regression analysis for differentiating AA from ARCD based on the results of the univariate analyses.

RESULTS

In the AA and ARCD groups, median ages were 35.5 and 41.0 years, respectively (p=0.011); median onset-to-visit intervals were 1 [interquartile range (IQR): 0-1] and 2 (IQR: 1-3) days, respectively (P < 0.001); median leukocyte counts were 12600 and 11500/mm³, respectively (P = 0.002); and median CRP levels were 1.1 (IQR: 0.2-4.1) and 4.9 (IQR: 2.9-8.5) mg/dL, respectively (P < 0.001). In the logistic regression model, odds ratios (ORs) were significantly high in nausea/vomiting (OR: 3.89, 95%CI: 2.04-7.42) and anorexia (OR: 2.13, 95%CI: 1.06-4.28). ORs were significantly lower with a longer onset-to-visit interval (OR: 0.84, 95%CI: 0.72-0.97), RLQ pain (OR: 0.28, 95%CI: 0.11-0.71), history of diverticulitis (OR: 0.034, 95%CI: 0.005-0.20), and CRP level > 3.0 mg/dL (OR: 0.25, 95%CI: 0.14-0.43). The regression model showed good calibration, discrimination, and optimism.

CONCLUSION

Clinical findings can differentiate AA and ARCD before imaging studies; nausea/vomiting and anorexia suggest AA, and longer onset-to-visit interval, RLQ pain, previous diverticulitis, and CRP level > 3.0 mg/dL suggest ARCD.

[Acute Suppurative Appendicitis Diagnosed by Acute Lower Gastrointestinal Hemorrhage]

A 49-year-old man visited the emergency room of Korea University Ansan Hospital with hematochezia starting the day before the visit. Recently, he was on anti-platelet medication due to hypertension. The patient had no definite symptoms other than hematochezia. Digital rectal exam was positive and laboratory tests showed severe anemia. Sigmoidoscopy was initiated and almost no fecal material was observed in the intestinal tract, allowing insertion into the cecum. Active bleeding from the appendiceal opening was noted. On abdominal CT, contrast enhancement was observed at the tip of the appendix. Under suspicion of acute appendicitis, we consulted with a surgeon. The patient underwent appendectomy with partial cecal resection. Pathologic examination revealed a diagnosis of appendix bleeding due to acute suppurative appendicitis. The patient had no further bleeding after surgery and was discharged in a stable state. Careful observation by the endoscopist is necessary for accurate diagnosis of lower gastrointestinal hemorrhage. Appendiceal hemorrhage is very rarely reported, but it has various pathophysiologies. CT scan is useful when appendiceal hemorrhage is confirmed by endoscopic findings. Surgical treatment was needed in almost all cases reported worldwide. If bleeding from the appendix is confirmed, surgical treatment should be considered for both therapeutic and diagnostic purposes.

Genetic association and differential expression of PITX2 with acute appendicitis

Appendicitis affects 9% of Americans and is the most common diagnosis requiring hospitalization of both children and adults. We performed a genome-wide association study of self-reported appendectomy with 18,773 affected adults and 114,907 unaffected adults of European American ancestry. A significant association with appendectomy was observed at 4q25 near the gene PITX2 (rs2129979, p value = 8.82 × 10-14) and was replicated in an independent sample of Caucasians (59 affected, 607 unaffected; p value = 0.005). Meta-analysis of the associated variant across our two cohorts and cohorts from Iceland and the Netherlands (in which this association had previously been reported) showed strong cumulative evidence of association (OR = 1.12; 95% CI 1.09-1.14; p value = 1.81 × 10-23) and some evidence for effect heterogeneity (p value = 0.03). Eight other loci were identified at suggestive significance in the discovery GWAS. Associations were followed up by measuring gene expression across resected appendices with varying levels of inflammation (N = 75). We measured expression of 27 genes based on physical proximity to the GWAS signals, evidence of being targeted by eQTLs near the signals according to RegulomeDB (score = 1), or both. Four of the 27 genes (including PITX2) showed significant evidence (p values < 0.0033) of differential expression across categories of appendix inflammation. An additional ten genes showed nominal evidence (p value < 0.05) of differential expression, which, together with the significant genes, is more than expected by chance (p value = 6.6 × 10-12). PITX2 impacts morphological development of intestinal tissue, promotes an anti-oxidant response, and its expression correlates with levels of intestinal bacteria and colonic inflammation. Further studies of the role of PITX2 in appendicitis are warranted.

Readmission after antibiotic management of uncomplicated acute appendicitis in adults: prospective study

BACKGROUND

Acute appendicitis is the most common surgical cause of acute abdomen. Many randomized studies compare between antibiotic and surgery, and such studies indicated that antibiotics might treat acute appendicitis. However, there are concerns about selection bias in previous studies. Hence, to overcome this worry; we used in this study a full-scale population-based application.

PATIENTS AND METHODS

We identified 327 adult patients who were admitted to surgical ward with diagnosis of uncomplicated acute appendicitis between March 2013 and February 2016. All patients received antibiotic therapy after confirming the diagnosis by computed tomography. Endpoints were treatment efficacy, readmission, and complications in 1 year of follow-up.

RESULTS

Of the 327 patients include in this study, 8 (2.5%) patients failed initial non-operative (antibiotic) management and underwent operation during their initial hospitalization. Of 319 available for 1-year follow-up, 280 patients (87.8%) did not require appendectomy; while 39 patients (12.2%) need readmission within 1 year.

CONCLUSIONS

Antibiotics are a safe and visible option in acute appendicitis management. This approach needs careful assessment and evaluation for each individual patient before it is used as the first-line therapy.

Evaluation of the microbiome in children's appendicitis

BACKGROUND/AIM

The role of the microbiome has been widely discussed in the etiology of appendicitis. The primary aim was to evaluate the microbiome in the normal appendix and in appendicitis specifically divided into the three clinically and histopathologically defined grades of inflammation. Secondary aims were to examine whether there were any microbiome differences between proximal and distal appendices, and relate the microbiome with histopathological findings.

METHODS

A prospective pilot study was conducted of children undergoing appendectomy for appendicitis. The diagnosis was based on histopathological analysis. Children with incidental appendectomy were used as controls. The proximal and distal mucosa from the appendices were analyzed with 16S rRNA gene sequencing.

RESULTS

A total of 22 children, 3 controls and 19 appendicitis patients; 11 phlegmonous, 4 gangrenous, and 4 perforated appendices, were prospectively included. The amount of Fusobacterium increased and Bacteroides decreased in phlegmonous and perforated appendicitis compared to controls, but statistical significance was not reached, and this pattern was not seen in gangrenous appendicitis. No relation could be seen between different bacteria and the grade of inflammation, and there was a wide variation of abundances at phylum, genus, and species level within every specific group of patients. Further, no significant differences could be detected when comparing the microbiome in proximal and distal mucosa, which may be because the study was underpowered. A trend with more abundance of Fusobacteria in the distal mucosa was seen in appendicitis patients with obstruction (25 and 13 %, respectively, p = 0.06).

CONCLUSION

The pattern of microbiome differed not only between groups, but also within groups. However, no statistically significant differences could be found in the microbiome between groups or clinical conditions. No correlation between a specific bacteria and grade of inflammation was found. In the vast majority of cases of appendicitis, changes in microbiome do not seem to be the primary event. Since there seem to be differences in microbiome patterns depending on the sample site, the exact localization of biopsy sampling must be described in future studies.

Diabetes increases the risk of an appendectomy in patients with antibiotic treatment of noncomplicated appendicitis

BACKGROUND

This retrospective cohort study examined whether diabetic patients have a higher risk for recurrent appendicitis during a 1-year follow-up period after successful antibiotic treatment for patients with acute uncomplicated appendicitis than nondiabetic patients using a population-based database.

METHODS

We included 541 appendicitis patients who received antibiotic treatment for acute appendicitis. We individually tracked each patient for a 1-year period to identify those who subsequently underwent an appendectomy during the follow-up period.

RESULTS

Cox proportional hazard regressions suggested that the adjusted hazard ratio of an appendectomy during the 1-year follow-up period was 1.75 for appendicitis patients with diabetes than appendicitis patients without diabetes. We found that among females, the adjusted hazard ratio of an appendectomy was 2.18 for acute appendicitis patients with diabetes than their counterparts without diabetes. However, we failed to observe this relationship in males.

CONCLUSIONS

We demonstrated a relationship between diabetes and a subsequent appendectomy in females who underwent antibiotic treatment for noncomplicated appendicitis.

Acute Appendicitis Is Associated with Peptic Ulcers: A Population-based Study

Despite some studies having indicated a possible association between appendicitis and duodenal ulcers, this association was mainly based on regional samples or limited clinician experiences, and as such, did not permit unequivocal conclusions. In this case-control study, we examined the association of acute appendicitis with peptic ulcers using a population-based database. We included 3574 patients with acute appendicitis as cases and 3574 sex- and age-matched controls. A Chi-squared test showed that there was a significant difference in the prevalences of prior peptic ulcers between cases and controls (21.7% vs. 16.8%, p < 0.001). The adjusted odds ratio (OR) of prior peptic ulcers for cases was 1.40 (95% confidence interval [CI]: 1.24~1.54, p < 0.001) compared to controls. The results further revealed that younger groups demonstrated higher ORs for prior peptic ulcers among cases than controls. In particular, the adjusted OR for cases < 30 years old was as high as 1.65 (95% CI = 1.25~2.19; p < 0.001) compared to controls. However, we failed to observe an association of acute appendicitis with peptic ulcers in the ≥ 60-year age group (OR = 1.19, 95% CI = 0.93~1.52). We concluded that there is an association between acute appendicitis and a previous diagnosis of peptic ulcers.

Acute appendicitis in children is associated with an abundance of bacteria from the phylum Fusobacteria

BACKGROUND

Although luminal obstruction has traditionally been viewed as the underlying cause of appendicitis, recent evidence has suggested that the disease may result directly from invasion by specific pathogens, e.g. Fusobacterium nucleatum. The purpose of this study was to survey microbial communities within pediatric appendectomy specimens using a culture-independent approach.

METHODS

We performed 16S ribosomal gene sequence analysis to profile the microbiota present within luminal fluid obtained from 22 pediatric appendectomy specimens. These included 10 simple appendicitis cases, 5 perforated appendicitis cases, 2 interval appendectomies, and 5 incidental appendectomies.

RESULTS

Samples could be divided into 2 distinct clusters based upon the composition of the appendiceal bacterial communities. Appendicitis samples contained an increased abundance of Fusobacterium spp. and a reduced abundance of Bacteroides spp. relative to non-appendicitis cases. Appendicitis samples also contained variable amounts of other oral taxa such as Porphyromonas, Parvimonas, and Gemella, whereas these taxa were generally absent from non-appendicitis samples.

CONCLUSIONS

Acute appendicitis is associated with an abundance of Fusobacterium spp. and other pathogens commonly found in the oral cavity. Further research is needed to determine whether these organisms directly cause appendicitis or rather proliferate in the appendix as a secondary consequence of inflammation.

Role of the faecolith in modern-day appendicitis

Introduction

The prevailing view on appendicitis is that the main aetiology is obstruction owing to faecoliths in adults and lymphoid hyperplasia in children. Faecoliths on imaging studies are believed to correlate well with appendicitis.

Methods

A retrospective chart review was conducted of 1,014 emergency appendicectomy patients between 2001 and 2011. Faecolith prevalence in adult and paediatric appendicectomy specimens with and without perforation was studied. The sensitivity and positive predictive value (PPV) of computed tomography (CT) for identifying faecoliths in the pathology specimen were examined.

Results

Overall, faecoliths were found in 18.1% (178/986) of appendicitis specimens and 28.6% (8/28) of negative appendicectomies. Faecolith prevalence for positive cases was 29.9% (79/264) in paediatric patients and 13.7% (99/722) in adults (p<0.05). Faecolith prevalence was 39.4% in perforated appendicitis but only 14.6% in non-perforated appendicitis (p<0.05). In adults, faecolith prevalence was 27.5% in perforated appendicitis and 12.0% in non-perforated appendicitis (p<0.05) while in paediatric patients, it was 56.1% in perforated appendicitis and 22.7% in non-perforated appendicitis (p=0.00). Sensitivity and PPV of preoperative CT in identifying faecoliths on pathology were 53.1% (86/162) and 44.8% (86/192) respectively.

Conclusions

Faecolith prevalence is too low to consider the faecolith the most common cause of non-perforated appendicitis. Faecoliths are more prevalent in paediatric appendicitis than in adult appendicitis. Preoperative CT is an unreliable predictor of faecoliths in pathology specimens.

Use of antibiotics alone for treatment of uncomplicated acute appendicitis: a systematic review and meta-analysis

BACKGROUND

The use of antibiotics alone in the treatment of uncomplicated acute appendicitis has been controversial. The present report is based on a systematic review and meta-analysis of existing studies that compared antibiotics treatment to appendectomy in patients with uncomplicated acute appendicitis.

METHODS

A Medline search was performed for studies published between 1970 and 2009. Studies were selected based on specific inclusion and exclusion criteria. Six reports comprised of 1,201 patients were analyzed.

RESULTS

In patients treated with antibiotics alone, 6.9 ± 4.4% failed to respond and required appendectomy, and acute appendicitis recurred in 14.2 ± 10.6%. One appendectomy patient had a recurrence. A normal appendix was found in 7.3 ± 5.1% of patients at appendectomy. Complications were considerably less likely to occur with antibiotic treatment than with appendectomy. Major surgical complications included enterocutaneous fistula and reoperation.

CONCLUSION

In some cases, antibiotic treatment may fail, and there is a risk of recurrence. However, surgically treated patients, including those with the potential for spontaneous resolution and those with a normal appendix, are subjected to the risks of operative morbidity and mortality. Antibiotic therapy incurs significantly fewer complications. Prospective randomized studies are urgently needed to conclusively define the roles of appendectomy and antibiotic treatment in the management of uncomplicated acute appendicitis.

Infectious causes of appendicitis

The pathologic spectrum of the inflamed appendix encompasses a wide range of infectious entities, some with specific histologic findings, and others with nonspecific findings that may require an extensive diagnostic evaluation. The appendix is exclusively involved in some of these disorders, and in others may be involved through extension from other areas of the gastrointestinal tract. This review discusses the pathologic features of bacterial, viral, fungal, and parasitic infections affecting the appendix, including adenovirus; cytomegalovirus; Yersinia, Actinomyces, Mycobacterium, or Histoplasma species; Enterobius vermicularis; schistosomiasis; and Strongyloides stercoralis. Pertinent ancillary diagnostic techniques and the clinical context and significance of the various infections are also discussed.

Progress of tissue injury in appendicitis involves the serine proteases uPA and PAI-1

OBJECTIVE

Serine proteases and the matrix metalloproteinases (MMPs) are key factors in the proteolytic cascade and participate in extracellular matrix (ECM) degradation. Fibrinolytic activators and inhibitors may have an effect on inflammatory cells, thereby modulating the inflammatory response. It is reasonable to assume that they may be implicated in the tissue injury in acute appendicitis that subsequently leads to appendix perforation. The purpose of this study was to investigate the expression and distribution of urokinase-type plasminogen activator (uPA) and plasminogen-activator inhibitor type 1 (PAI-1) in appendicitis.

MATERIAL AND METHODS

Expression of uPA and expression of PAI-1 were measured in tissue specimens from patients with appendicitis (n=30) and in control specimens (n=9), using the quantitative ELISA technique. Distribution of enzymes was studied with immunohistochemistry. The uPA and PAI-1 levels in the subgroups of appendicitis and controls were compared.

RESULTS

The overall expressions of uPA and PAI-1 were greater in appendicitis than in control specimens (p <0.001 and p<0.0001, respectively). Expressions of uPA and PAI-1 in phlegmonous (n=15), gangrenous (n=6) and perforated appendicitis (n=9) were all higher than those in controls (n=9), (p<0.01). Moreover, the PAI-1 level was elevated in perforated appendicitis compared with phlegmonous appendicitis (p<0.01). uPA staining was observed in connection with vascular endothelial cells and the serosa stained intensely in specimens from perforated appendicitis.

CONCLUSIONS

The expression of uPA and especially the over-expression of PAI-1 seem to correlate to the progression of local inflammatory response in acute appendicitis.

Appendicitis and infections of the appendix

The pathologic spectrum of the acutely inflamed appendix encompasses a wide range of infectious and noninfectious entities. The appendix suffers alone in some of these disorders, and in others may be involved through extension from other areas of the gastrointestinal tract. Although the appendix is the most commonly resected and examined intraabdominal organ, the pathogenesis and etiology of acute nonspecific appendicitis (the most common diagnosis made in this organ) remains enigmatic. This review encompasses the pathology, pathogenesis, and bacteriology of acute appendicitis, as well as controversial issues such as the diagnosis of chronic appendicitis and the significance of a morphologically unremarkable appendectomy specimen in the clinical context of appendicitis. In addition, the pathologic features, pertinent diagnostic techniques, and clinical significance of several specific bacterial, viral, fungal, and parasitic infections affecting the appendix are presented, including adenovirus, cytomegalovirus, Yersinia species, actinomycosis, Mycobacteria species, histoplasmosis, pinworms, schistosomiasis, and Strongyloides stercoralis.

Protocol-based approach to suspected appendicitis, incorporating the Alvarado score and outpatient antibiotics

BACKGROUND

There is evidence that antibiotics can be used as primary treatment for appendicitis, however, delayed surgical treatment might still be associated with perforation. Most patients at risk of perforation have high Alvarado scores. We designed a protocol-based approach to suspected appendicitis, in which the Alvarado score was used to select patients for early treatment with surgery or outpatient antibiotics.

METHODS

Patients included in the present study were adults and children referred to the surgical service at John Hunter Hospital (Newcastle, Australia) with suspected appendicitis in the 12 months from July 2000. Treatment groups: no treatment (Alvarado score 1-4); antibiotics alone (Alvarado 5-7); early surgery (Alvarado 8-10).

OUTCOME MEASURES

time to operation; duration of hospital stay; non-therapeutic operations; delayed treatment in association with perforation; recurrent appendicitis (for those treated with antibiotics). Comparison group: 142 patients managed with 'best clinical practice' as part of an earlier trial.

RESULTS

One hundred and twenty-two patients were enrolled. Median time to operation was 3.9 h (comparison group 7.3 h, P = 0.014). Median length of stay was 38.5 h (comparison group 44.2 h, P = 0.041). There were two cases of delayed treatment in association with perforation (2/122 = 1.6%, comparison group 2/142 = 1.4%, P = 0.88) and 10 non-therapeutic operations (10/122 = 8.1%, comparison group 15/142 = 10.6%, P = 0.51). Of those whose initial illness was treated successfully with antibiotics, 2/42 (4.8%) subsequently required appendicectomy.

CONCLUSIONS

This protocol-based approach to suspected appendicitis is feasible. A prospective controlled study would be required to confirm potential benefits (in terms of short hospital stay) and to confirm that there is not an increase in adverse outcomes.

Appendectomy is followed by increased risk of Crohn's disease

BACKGROUND & AIMS

Appendectomy is associated with a low risk of subsequent ulcerative colitis. This study analyzes the risk of Crohn's disease after appendectomy.

METHODS

We followed-up 212,218 patients with appendectomy before age 50 years and a cohort of matched controls, identified from the Swedish Inpatient Register and the nationwide Census, for any subsequent diagnosis of Crohn's disease.

RESULTS

An increased risk of Crohn's disease was found for more than 20 years after appendectomy, with incidence rate ratio 2.11 (95% confidence interval [CI], 1.21-3.79) after perforated appendicitis, 1.85 (95% CI, 1.10-3.18) after nonspecific abdominal pain, 2.15 (95% CI, 1.25-3.80) after mesenteric lymphadenitis, 2.52 (95% CI, 1.43-4.63) after other diagnoses. After nonperforated appendicitis, there was an increased risk among women but not among men (incidence rate ratio 1.37; 95% CI, 1.03-1.85, respectively, 0.89, 95% CI, 0.64-1.24). Patients operated on before age 10 years had a low risk (incidence rate ratio 0.48, 95% CI, 0.23-0.97). Crohn's disease patients with a history of perforated appendicitis had a worse prognosis.

CONCLUSIONS

Appendectomy is associated with an increased risk of Crohn's disease that is dependent on the patient's sex, age, and the diagnosis at operation. The pattern of associations suggests a biologic cause.

The pathology of acute appendicitis

Although acute appendicitis is frequent, it is subject to common misconceptions. Furthermore, there is little good evidence to support some of our beliefs. This report reviews the role of the anatomic pathologist in diagnosis when acute appendicitis is suspected clinically and discusses what is known of its pathology. The conclusions that can be legitimately drawn from the literature are emphasized. A classification is proposed that incorporates intraluminal inflammation, acute mucosal inflammation, acute mucosal and submucosal inflammation, suppurative (phlegmonous) appendicitis, gangrenous appendicitis, and periappendicitis, and the significance of each of these diagnoses is discussed. The etiology and pathogenesis of acute appendicitis is reviewed. Contrary to popular belief, the best evidence indicates that obstruction is unlikely to be the primary cause, at least in the majority of cases. Ancillary techniques in the diagnosis of appendicitis, including laparoscopy and peritoneal aspiration cytology, are discussed.

The diagnostic challenge of postoperative acute appendicitis

During the period 1979 to 1989, 0.1% of all cases of acute appendicitis at our institution occurred soon after another operative procedure. The interval between primary operation and appendectomy was 5 to 31 days (mean, 14 days). Signs and symptoms did not differ from those of classical acute appendicitis. Duration of symptoms ranged from 12 hours to 8 days (mean, 2.4 days). Perforation was present in 3 patients, suppurative appendicitis in 1 patient, and acute inflammation in 4 patients. Two of the perforations were associated with abscess formation. Morbidity related to the appendiceal condition included hepatic abscesses, septic shock, and prolonged ileus. There was no mortality. Hospitalization ranged from 6 to 80 days (mean, 12.5 days).

New insights into the pathogenesis of appendicitis based on immunocytochemical analysis of early immune response

Although appendicitis is the most common condition requiring emergency surgery, the pathogenesis of this disease is poorly understood. In this study, local immune responses in acute appendicitis were investigated, using an experimental rabbit model, as well as in different grades of appendicitis in humans. Polymorphonuclear leukocyte (PMN) and plasma cell isotypes infiltration was measured in 24 New Zealand-bred white rabbits following experimental obstruction of the appendiceal lumen for periods ranging from 30 minutes to 24 hours. Significant infiltration of PMNs, IgM, and IgG plasma cells was noted at 30 minutes following obstruction, and IgA plasma cells were noted at 2 hours after obstruction. The immunopathological features observed in the study of human appendicitis clearly demonstrated the role of plasma cell infiltration in the immunopathogenesis of appendicitis. IgA and IgG plasma cells were significantly increased in the lamina propria of both focal and acute suppurative appendicitis, compared with controls (P less than .001). In focal appendicitis, in which the focus of inflammation is confined to only a few serial sections, the increased IgA and IgG plasma cell infiltration was present throughout the entire length of the resected organ. The possibility, as seen in this study, that antigen stimulation of the effector immune system could give rise to appendicitis, provides new insights into the diversity of inflammatory responses contributing to diseases of the intestinal tract. This previously unrecognised concept in the pathogenesis of appendicitis requires further elucidation of the stimulating agent, and in particular the T-cell recognition process.

Experimental model for the study of the human appendix

A simple and reproducible model for the experimental study of the normally functioning human appendix is described. The appendix removed from a human is transplanted into a nude mouse and is kept vital for at least 4 hours. This model is an improvement on previous models. It corresponds well with the working of the normal human appendix as regards tissue type and characteristics. Results are easily quantified and a paired control is possible in the experimental animal. This simplifies the experimental design and statistical calculations. The model can be used to gain additional information about the pathophysiology of the human appendix and the possible influence of drugs on this organ.

Familial retrocaecal appendicitis

Four members of the same family operated on for acute retrocaecal appendicitis are reported. It is suggested that they provide further support for the hypothesis that an hereditary factor might be involved in the pathogenesis of acute appendicitis.

A cluster of true appendicitis cases

A cluster of cases of appendicitis occurred primarily in school-age boys in a small Texas town. The expected rate of appendicitis is 1.5 cases per 1,000 persons, or about 1 case per month in that town. However, in the spring of 1984, 13 cases, 10 in school-age boys, occurred. In eight of these patients, the initial onset of abdominal pain occurred over a 15 day period. A case controlled study of school-age patients indicated that sweets in the diet and consumption of local farm eggs may have been associated with the appendicitis. We hypothesize that a group of young male patients who were susceptible to appendicitis because of the high sugar content of their diets were exposed to a bacterium or virus that precipitated this outbreak of appendicitis.