A novel biomarker panel to rule out acute appendicitis in pediatric patients with abdominal pain

Diagnostic accuracy of blood tests of inflammation in paediatric appendicitis: a systematic review and meta-analysis

OBJECTIVE

Possible childhood appendicitis is a common emergency presentation. The exact value of blood tests is debated. This study sought to determine the diagnostic accuracy of four blood tests (white cell count (WCC), neutrophil(count or percentage), C reactive protein (CRP) and/or procalcitonin) for childhood appendicitis.

DESIGN

A systematic review and diagnostic meta-analysis. Data sources included MEDLINE, EMBASE, Central, Web of Science searched from inception-March 2022 with reference searching and authors contacted for missing/unclear data. Eligibility criteria was studies reporting the diagnostic accuracy of the four blood tests compared to the reference standard (histology or follow-up). Risk of bias was assessed (QUADAS-2), pooled sensitivity and specificity were generated for each test and commonly presented cut-offs. To provide insight into clinical impact, we present strategies using a hypothetical cohort.

RESULTS

67 studies were included (34 839 children, 13 342 with appendicitis), all in the hospital setting. The most sensitive tests were WCC (≥10 000 cells/µL, 53 studies sensitivity 0.85 (95% CI 0.80 to 0.89)) and absolute neutrophil count (ANC) (≥7500 cells/µL, five studies sensitivity 0.90 (95% CI 0.85 to 0.94)). Combination of WCC or CRP increased sensitivity further(≥10 000 cells/µL or ≥10 mg/L, individual patient data (IPD) of 6 studies, 0.97 (95% CI 0.93 to 0.99)).Applying results to a hypothetical cohort(1000 children with appendicitis symptoms, of whom 400 have appendicitis) 60 and 40 children would be wrongly discharged based solely on WCC and ANC, respectively, 12 with combination of WCC or CRP.The most specific tests were CRP alone (≥50 mg/L, 38 studies, specificity 0.87 (95% CI 0.80 to 0.91)) or combined with WCC (≥10 000 cells/µL and ≥50 mg/L, IPD of six studies, 0.93 (95% CI 0.91 to 0.95)).

CONCLUSIONS

The best performing single blood tests for ruling-out paediatric appendicitis are WCC or ANC; with accuracy improved combining WCC and CRP. These tests could be used at the point of care in combination with clinical prediction rules. We provide insight into the best cut-offs for clinical application.

PROSPERO REGISTRATION NUMBER

CRD42017080036.

The Use of Inflammatory Markers to Rule Out Acute Appendicitis in Pediatrics

Background Acute appendicitis is the most common abdominal surgical emergency in pediatric patients. The diagnosis of acute appendicitis in pediatrics is challenging and requires an accurate physical examination, laboratory study, and imaging. The aim of this study was to determine the benefits of using three inflammatory markers, white blood count (WBC), neutrophils percent (NE%), and C-reactive protein (CRP), in ruling out appendicitis in pediatric patients. Methods A retrospective study was conducted of 152 pediatric patients aged between 6 months and 14 years presenting to the emergency department between January 2018 and December 2020, with the diagnosis of appendicitis as the primary physician's main diagnosis. Demographic information and clinical data were extracted from the medical file for each patient. Results Out of the 152 patients included, 68 (44.7%) were female and 84 (55.3%) were male, with median age was 8.1 years. Thirty-six (23.7%) had acute appendicitis confirmed by histopathology. Of these 36 patients, only two patients (5.6%) had all inflammatory markers within normal limits. Conclusion  Although raised inflammatory markers may help diagnose acute appendicitis, their role in ruling it out remains limited.

Diagnostic value of monocyte-lymphocyte ratio and red cell distribution width- lymphocyte ratio against other biomarkers in children with acute appendicitis, cross-sectional study

Our study aims to ascertain the diagnostic value of the Monocyte-lymphocyte ratio (MLR) and red cell distribution width (RDW)-lymphocyte ratio (RLR) by comparing them with other biomarkers in distinguishing patients with and without acute appendicitis (AA). A total of 223 children were recruited in the study conducted according to the Cross-Sectional Study design. Patients under 18 years were assigned to 3 groups; AA, nonspecific abdominal pain (NAP), and a control group. According to the outcome of our research, while C-reactive protein (CRP), white blood cell (WBC), neutrophil count (NEU), neutrophil to lymphocyte ratio (NLR), and MLR had excellent diagnostic power, RLR had acceptable diagnostic power, and platelet to lymphocyte ratio (PLR) had only fair diagnostic power. MLR and NLR, which are simple, inexpensive, and easily accessible parameters, can be recommended to be used together with other biomarkers in diagnosing AA in children.

On the Way to Improve Diagnostic Marker Panel for Acute Appendicitis in Adults: the Role of Calprotectin

Calprotectin is a positive acute-phase protein participating in innate immune responses and inflammatory processes. This protein is produced mainly in neutrophils, which infiltrate inflamed tissues and then increase the level of calprotectin in plasma, urine, or body secretions. Its measurement is used in the diagnosis of many inflammatory diseases of the gastrointestinal tract. Here, we reviewed the studies evaluating the utility of calprotectin when the patient is suspected of acute appendicitis, one of the most common causes of abdominal pain. Fecal and serum calprotectin provide clinicians additional information as compared to routinely performed laboratory analyses. Moreover, among all forms of the protein, the fecal calprotectin seems to be a particularly promising biomarker due to its high resistance to degradation in the stool. In the future, innovative methods in the form of neural networks may play a valuable role in developing such panels. These findings are important because current literature showed that sensitive and specific markers of acute appendicitis are still urgently needed.

Signs and syndromes in acute appendicitis: A pathophysiologic approach

Physical examination signs have not been well studied, and their accuracy and reliability in diagnosis remain unknown. The few studies available are limited in that the method of performing the sign was not stated, the technique used was not standardized, and the position of the appendix was not correlated with imaging or surgical findings. Some appendiceal signs were written in a non-English language and may not have been appropriately translated (e.g., Blumberg-Shchetkin and Rovsing). In other cases, the sign described differs from the original report (e.g., Rovsing, Blumberg-Shchetkin, and Cope sign, Murphy syndrome). Because of these studies limitations, gaps remain regarding the signs’ utility in the bedside diagnosis of acute appendicitis. Based on the few studies available with these limitations in mind, the results suggest that a positive test is more likely to be found in acute appendicitis. However, a negative test does not exclude the diagnosis. Hence, these tests increase the likelihood of ruling in acute appendicitis when positive but are less helpful in ruling out disease when negative. Knowledge about the correct method of performing the sign may be a valuable adjunct to the surgeon in further increasing their pretest probability of disease. Furthermore, it may allow surgeons to study these signs further to better understand their role in clinical practice. In the interim, these signs should continue to be used as a tool to supplement the clinical diagnosis.

Diagnostic performance of calprotectin and APPY-1 test in pediatric acute appendicitis: a systematic review and a meta-analysis

BACKGROUND

Pediatric acute appendicitis (AA) is a challenging pathology to diagnose. In the last decades, multiple biomarkers have been evaluated in different human biological samples to improve diagnostic performance. This study aimed to examine the diagnostic performance of serum, fecal and urinary calprotectin as well as the role of the APPY-1 biomarker panel in pediatric acute appendicitis.

METHODS

We conducted a systematic review of the literature that involved an extensive search in the main databases of medical bibliography (Medline, PubMed, Web of Science and SciELO). Two independent reviewers selected the relevant articles based on the previously defined inclusion and exclusion criteria. Methodological quality of the selected article was rated using the QUADAS2 index. Data extraction was performed by two independent reviewers. A synthesis of the results, a standardization of the metrics and two random-effect meta-analyses, one for serum calprotectin and one for APPY-1, were performed.

RESULTS

The research resulted in 173 articles. Thirty-eight duplicates were removed. Among the remaining 135 articles, we excluded 125 following the inclusion and exclusion criteria, resulting in the 10 studies included in this review. This systematic review included data from of 3901 participants (1276 patients with confirmed diagnosis of AA and 2625 controls). The age of the participants ranged from 0 to 21 years. Four of the studies compared serum calprotectin values and reported significant differences between groups, but inconsistent results regarding cutoff points, sensitivity and specificity. Two publications compared urinary values of calprotectin and presented inconsistent results regarding sensitivity and specificity as well. One publication evaluated the diagnostic performance of fecal calprotectin, but it did not provide data on measured values. Four studies evaluated the diagnostic performance of APPY-1 test in pediatric acute appendicitis. The calculated pooled sensitivity and specificity of those studies were 97.37 (95% CI 95.60-98.44) and 36.74 (95% CI 32.28-41.44), respectively, and the calculated pooled NLR, 0.0714 (95% CI 0.041-0.115).

CONCLUSION

Serum calprotectin has limited diagnostic yield in pediatric acute appendicitis. Its performance seems to increase with the hours of clinical evolution and in advanced AA, although the evidence is limited. There is not enough evidence on the usefulness of urinary or fecal calprotectin in the diagnosis of pediatric acute appendicitis. On the other hand, the APPY-1 is a reliable test to exclude the diagnosis of AA in patients at low or moderate risk according to PAS and Alvarado Score.

Physical Examination and Appendiceal Signs During Pregnancy

The clinical diagnosis of acute appendicitis is challenging as patients present with an array of objective and subjective symptoms early or late in the disease course. Ultrasound is routinely performed in all patients with suspected acute appendicitis. Equivocal test results frequently require further assessments using other imaging techniques that are limited in scope during pregnancy because of issues involving safety, availability, and accessibility. Physical examination diagnostic signs in acute appendicitis during pregnancy have not been well studied. Studies failed to describe, standardize, or correlate the technique used to the pathologic disease process. Therefore, gaps remain in current knowledge regarding the usefulness and application of these tests during the physical examination. Improvement in diagnostic acumen is critically important, particularly in cases where there remains diagnostic uncertainty because of equivocal imaging results. This article reviews signs used to diagnose patients with acute appendicitis using a pathophysiologic approach based on visceral and cerebrospinal nerve pathways to explain the mechanism for a positive test result. It also suggests a framework to study them further to better understand their role, if any, in clinical practice.

Integration of Physical Examination, Old and New Biomarkers, and Ultrasonography by Using Neural Networks for Pediatric Appendicitis

OBJECTIVE

The objective of this study was to evaluate physical examinations, imaging, and laboratory analyses individually and combined using innovative statistical analysis methods for the accurate diagnosis of pediatric appendicitis.

METHODS

Patients admitted to hospital with symptoms of abdominal pain whose pediatric appendicitis scores greater than 3 were included in the study. Clinical, radiologic, and laboratory findings and as a new biomarker calprotectin (CPT) concentrations were evaluated individually and combined using artificial neural networks (ANNs), which revealed latent relationships for a definitive diagnosis.

RESULTS

Three hundred twenty patients were evaluated (190 appendicitis [43 perforated] vs 130 no appendicitis). The mean ± SD age was 11.3 ± 3.6 years and 63% were male. Pediatric appendicitis scores, white blood cell (WBC) count, absolute neutrophil count (ANC), C-reactive protein (CRP) level, procalcitonin (PCT) and CPT concentrations were higher in the appendicitis group; however, only WBC and ANC were higher in first 24 hours of pain. White blood cells and CRP were diagnostic markers in patients whose appendix could not be visualized using ultrasonography (US). On classic receiver operating characteristic (ROC) analysis, the areas under the curve (AUCs) were not strong enough for differential diagnosis (WBC, 0.73; ANC, 0.72; CRP, 0.65; PCT and CPT, 0.61). However, when the physical examination, US, and laboratory findings were analyzed in a multivariate model and the ROC analysis obtained from the variables with ANN, an ROC curve could be obtained with 0.91 AUC, 89.8% sensitivity, and 81.2% specificity. C-reactive protein and PCT were diagnostic for perforated appendicitis with 0.83 and 0.75 AUC on ROC.

CONCLUSIONS

Although none of the biomarkers were sufficient for an accurate diagnosis of appendicitis individually, a combination of physical examination and laboratory and US was a good diagnostic tool for pediatric appendicitis.

Markers of neutrophil activation and extracellular trap formation predict appendicitis

BACKGROUND

Although appendicitis is one of the most frequently occurring pediatric surgery emergencies, current biomarkers for diagnosis are unspecific and have low predictive values. Neutrophils are an essential component of the innate immune system involved during appendicitis. Thus, the current study aimed to evaluate neutrophils and their activation markers in a prospective cohort study.

METHODS

The study population included all children with acute abdominal pain who presented to the pediatric surgery department of 2 large clinics between July 2018 and December 2019. All enrolled subjects underwent blood sample collection with an assessment of white blood cell count, C-reactive protein, cell-free DNA, neutrophil elastase, myeloperoxidase, and citrullinated histone H3. If an appendectomy was performed, the appendix was stained for myeloperoxidase, neutrophil elastase, and citrullinated histone H3 using immunofluorescence.

RESULTS

In total, 198 subjects were included in the study, of whom 133 had histological verified appendicitis. In those with appendicitis, white blood cell count and C-reactive protein showed a moderate diagnostic value for (noncomplicated and complicated) appendicitis. However, cell-free DNA (area under the curve .87) and citrullinated histone H3 (area under the curve .88) demonstrated excellent predictive power for appendicitis. Most notably, citrullinated histone H3 was able to distinguish (1) noncomplicated from complicated appendicitis, and (2) predict patient outcome. Moreover, the examined biomarkers appear to reflect tissue expression and disease severity.

CONCLUSION

Markers of neutrophil activation and extracellular trap formation are excellent biomarkers for appendicitis. In particular, citrullinated histone H3 may be used to identify children with an increased risk of developing complications after appendicitis.

Novel molecular biomarkers and diagnosis of acute appendicitis in children

Reliable and efficient diagnosis of pediatric appendicitis is essential for the establishment of a clinical management plan and improvement of patient outcomes. Current strategies used to diagnose a child presenting with a suspected appendicitis include laboratory studies, clinical scores and diagnostic imaging. Although these modalities work in conjunction with each other, one optimal diagnostic strategy has yet to be agreed upon. The recent introduction of precision medicine techniques such as genomics, transcriptomics, proteomics and metabolomics has increased both the diagnostic sensitivity and specificity of appendicitis. Using these novel strategies, the integration of precision medicine into clinical practice via point-of-care technologies is a plausible future. These technologies would assist in the screening, diagnosis and prognosis of pediatric appendicitis.

Preoperatively predicting the pathological types of acute appendicitis using machine learning based on peripheral blood biomarkers and clinical features: a retrospective study

Background

This study aimed to establish machine learning models for preoperative prediction of the pathological types of acute appendicitis.

Methods

Based on histopathology, 136 patients with acute appendicitis were included and divided into three types: acute simple appendicitis (SA, n=8), acute purulent appendicitis (PA, n=104), and acute gangrenous or perforated appendicitis (GPA, n=24). Patients with SA/PA and PA/GPA were divided into training (70%) and testing (30%) sets. Statistically significant features (P<0.05) for pathology prediction were selected by univariate analysis. According to clinical and laboratory data, machine learning logistic regression (LR) models were built. Area under receiver operating characteristic curve (AUC) was used for model assessment.

Results

Nausea and vomiting, abdominal pain time, neutrophils (NE), CD4⁺ T cell, helper T cell, B lymphocyte, natural killer (NK) cell counts, and CD4⁺/CD8⁺ ratio were selected features for the SA/PA group (P<0.05). Nausea and vomiting, abdominal pain time, the highest temperature, CD8⁺ T cell, procalcitonin (PCT), and C-reactive protein (CRP) were selected features for the PA/GPA group (P<0.05). By using LR models, the blood markers can distinguish SA and PA (training AUC =0.904, testing AUC =0.910). To introduce additional clinical features, the AUC for the testing set increased to 0.926. In the PA/GPA prediction model, AUC with blood biomarkers was 0.834 for the training and 0.821 for the testing set. Combining with clinical features, the AUC for the testing set increased to 0.854.

Conclusions

Peripheral blood biomarkers can predict the pathological type of SA from PA and GPA. Introducing clinical symptoms could further improve the prediction performance.

The Use of Fecal Calprotectin Testing in Paediatric Disorders: A Position Paper of the European Society for Paediatric Gastroenterology and Nutrition Gastroenterology Committee

OBJECTIVES

The aim of the study was to review the evidence regarding the clinical use and value of fecal calprotectin (FC) measurements in different gastrointestinal disorders in children.

METHODS

A literature search was conducted in the PubMed, MEDLINE, EMBASE, and Cochrane databases until October 31, 2019. Subtopics were identified and each assigned to individual authors.

RESULTS

A total of 28 recommendations were voted on using the nominal voting technique. Recommendations are given related to sampling, measurement methods, and results interpretation. The 14 authors anonymously voted on each recommendation using a 9-point scale (1 strongly disagree to 9 fully agree). Consensus was considered achieved if at least 75% of the authors voted 6, 7, 8, or 9.

CONCLUSIONS

Consensus was reached for all recommendations. Limitations for the use of FC in clinical practice include variability in extraction methodology, performance of test kits as well as the need to establish local reference ranges because of the influence of individual factors, such as age, diet, microbiota, and drugs. The main utility of FC measurement at present is in the diagnosis and monitoring of inflammatory bowel disease (IBD) as well as to differentiate it from functional gastrointestinal disorders (FAPDs). FC, however, has neither utility in the diagnosis of infantile colic nor to differentiate between functional and organic constipation. A rise in FC concentration, may alert to the risk of developing necrotizing enterocolitis and help identifying gastrointestinal involvement in children with Henoch-Schönlein purpura. FC measurement is of little value in Cow's Milk Protein Allergy, coeliac disease (CD), and cystic fibrosis. FC does neither help to distinguish bacterial from viral acute gastroenteritis (AGE), nor to diagnose Helicobacter Pylori infection, small intestinal bacterial overgrowth (SIBO), acute appendicitis (AA), or intestinal polyps.

Markers of neutrophil activation and extracellular traps formation are predictive of appendicitis in mice and humans: a pilot study

Appendicitis is one of the most frequent emergencies in pediatric surgery, yet current biomarkers for diagnosis are unspecific and have low predictive values. As neutrophils and extracellular traps (ETs) are an essential component of the immune defense against bacterial infections, and appendicitis is considered an inflammation reaction of the appendix, we hypothesized that neutrophil activation and NET formation play an essential role in appendicitis development and maintenance. Therefore, this pilot study aimed to establish a murine model of appendicitis and to evaluate ETs markers to diagnose appendicitis in mice and humans. The study used 20 (12 appendicitis- and 8 controls) 6-week old mice which underwent advanced appendicitis induction using a modified caecal ligation puncture procedure. During the study, cell-free DNA, neutrophil elastase (NE), myeloperoxidase (MPO), and citrullinated Histone H3 (H3cit) were assessed. Additionally, samples of 5 children with histologically confirmed appendicitis and 5 matched controls with catarrhal appendicitis, were examined for the same biomarkers. Moreover, NE, MPO, and H3cit were assessed histologically via immunofluorescence in mice and humans. All mice in the appendicitis group developed an advanced form of appendicitis with focal peritonitis. In mice and humans with appendicitis, markers of neutrophil activation and ETs formation (especially cfDNA, NE and H3cit) were significantly elevated in blood and tissue compared to controls. Ultimately, biomarkers correlated extremely well with tissue expression and thus disease severity. It appears that neutrophil activation and possibly NETs contribute to appendicitis development and biomarkers of neutrophil activation and ET formation reflect disease severity and thus could be used as biomarkers for appendicitis. However, large prospective clinical studies are needed to confirm our findings.

Diagnostic accuracy of combined WBC, ANC and CRP in adult emergency department patients suspected of acute appendicitis

OBJECTIVES

To assess the sensitivity, specificity, and negative predictive value (NPV) of normal total white blood cell count (WBC) and normal absolute neutrophil count (ANC) combined with a normal proprietary C-reactive protein (pCRP) level in adult emergency department (ED) patients with abdominal pain suspected of possible acute appendicitis.

METHODS

We prospectively enrolled patients ≥18 years of age at seven U.S. emergency departments with ≤72 h of abdominal pain and other signs and symptoms suggesting possible acute appendicitis. Sensitivity, specificity, and NPV for normal WBC and ANC combined with normal pCRP were correlated with the final diagnosis of acute appendicitis.

RESULTS

We enrolled 422 patients with a prevalence of acute appendicitis of 19.1%. The combination of normal WBC and pCRP exhibited a sensitivity of 97.5% (95% CI, 91.3-99.3%), an NPV of 98.8% (95% CI, 95.9-99.7%) and a specificity of 50.0% (95% CI, 44.7-55.3%) for acute appendicitis. Normal ANC and pCRP resulted in a sensitivity of 100% (95% CI, 95.4-100%), a negative predictive value of 100% (95% CI, 97.5-100%) and a specificity of 44.4% (95% CI, 39.2-49.7%) for acute appendicitis. Normal WBC and pCRP correctly identified 171 of 342 (50.0%) patients who did not have appendicitis with 2 (2.5%) false negatives, while normal ANC and pCRP identified 150 of 338 (44.3%) of patients without appendicitis with no false negatives.

CONCLUSION

The combination of normal WBC and ANC with normal pCRP levels exhibited high sensitivity and negative predictive value for acute appendicitis in this prospective adult patient cohort. Confirmation and validation of these findings with further study using commercially available CRP assays is needed.

Determination of pentraxin 3 levels in diagnosis of appendicitis in children

BACKGROUND

The aim of this study is to determine whether pentraxin 3 (PTX3) levels can be used in the diagnosis of appendicitis in children.

METHODS

Fifteen children under 18 years old, who gave blood samples for reasons other than inflammatory conditions, and 40 children who were proved to have appendicitis (non-perforated or perforated) between August 2017 and January 2018, were enrolled in the study. Patients were classified into subgroups: group 1 (healthy children without any sign of inflammation, n = 15), group 2 (non-perforated appendicitis, n = 25), and group 3 (perforated appendicitis, n = 15).

RESULTS

The median PTX3 value was 1.01 ng/mL (minimum value: 0.82, maximum: 1.28) in the control group. The median PTX3 values prior to surgery were 20.68 ng/mL (minimum: 1.02, maximum: 28.471) and 1.46 (minimum: 1.05, maximum: 23.421) ng/mL for non-perforated appendicitis and perforated appendicitis respectively. The PTX3 levels were significantly higher in groups 2 and 3 than in group 1 (P < 0.01). According to receiver operating characteristics analysis the cut-off value of PTX3 levels at admission for appendicitis was 1.30 ng/mL with a sensitivity of 75% and a specificity of 100% (area under the curve, 0.939; P = 0.000).

CONCLUSIONS

Pentraxin 3 levels were significantly higher in children with appendicitis than in healthy children. Children with high PTX3 levels complaining of right lower quadrant pain may support a diagnosis of appendicitis. Future studies should be conducted to evaluate changes in PTX3 levels by comparing children with appendicitis versus acute abdominal pain in larger populations to further determine the value of PTX3 in the diagnosis of appendicitis in children.

Diagnosis and classification of pediatric acute appendicitis by artificial intelligence methods: An investigator-independent approach

Acute appendicitis is one of the major causes for emergency surgery in childhood and adolescence. Appendectomy is still the therapy of choice, but conservative strategies are increasingly being studied for uncomplicated inflammation. Diagnosis of acute appendicitis remains challenging, especially due to the frequently unspecific clinical picture. Inflammatory blood markers and imaging methods like ultrasound are limited as they have to be interpreted by experts and still do not offer sufficient diagnostic certainty. This study presents a method for automatic diagnosis of appendicitis as well as the differentiation between complicated and uncomplicated inflammation using values/parameters which are routinely and unbiasedly obtained for each patient with suspected appendicitis. We analyzed full blood counts, c-reactive protein (CRP) and appendiceal diameters in ultrasound investigations corresponding to children and adolescents aged 0–17 years from a hospital based population in Berlin, Germany. A total of 590 patients (473 patients with appendicitis in histopathology and 117 with negative histopathological findings) were analyzed retrospectively with modern algorithms from machine learning (ML) and artificial intelligence (AI). The discovery of informative parameters (biomarker signatures) and training of the classification model were done with a maximum of 35% of the patients. The remaining minimum 65% of patients were used for validation. At clinical relevant cut-off points the accuracy of the biomarker signature for diagnosis of appendicitis was 90% (93% sensitivity, 67% specificity), while the accuracy to correctly identify complicated inflammation was 51% (95% sensitivity, 33% specificity) on validation data. Such a test would be capable to prevent two out of three patients without appendicitis from useless surgery as well as one out of three patients with uncomplicated appendicitis. The presented method has the potential to change today’s therapeutic approach for appendicitis and demonstrates the capability of algorithms from AI and ML to significantly improve diagnostics even based on routine diagnostic parameters.

A new clinical score to identify children at low risk for appendicitis

BACKGROUND

Besides clinical signs and imaging, in recent years, biomarkers have proven to be a viable diagnostic resource for acute appendicitis (AA).

OBJECTIVE

The objective of this study was to develop a clinical score including clinical signs and a combination of biomarkers to identify children with abdominal pain at low risk of AA.

DESIGN/METHODS

We prospectively included children 2 to 14 years of age with abdominal pain suggestive of AA who presented to the emergency department between July 2016 and September 2017. A new score, the Pediatric Appendicitis Laboratory Score (PALabS) including clinical signs, leucocyte (WBC) and neutrophil (ANC) counts and plasma C-reactive protein (CRP) and calprotectin (CP) levels was developed and validated through secondary analyses of two distinct cohorts The validation sample included visits to a single pediatric emergency department from 2012 to 2013 and 2016 to 2017.

RESULTS

The derivation sample included 278 children, 35.9% of whom had AA and the validation sample included 255 children, 49% of whom had AA. Using logistic regression, we created a 6-part score that consisted of nausea (3 points), history of focal right lower quadrant pain (4 points), ANC of ≥7500/μL (7 points), WBC of ≥10,000/μL (4 points), CRP ≥ 10.0 mg/L (2 points) and CP ≥ 0.50 ≥ ng/mL (3 points). This score exhibited a high discriminatory power (area under the curve: 0.88; 95% confidence interval: 0.84 to 0.92) and outperformed the PAS and Kharbanda scores (area under the curve: 0.76; 95% confidence interval: 0.71 to 0.82 and 0.82; 95% confidence interval: 0.77 to 0.87, respectively). A PALabS ≤6 had a sensitivity of 99.2% (95% confidence interval [CI]: 95.6-99.9), negative predictive value of 97.6% (95% CI: 87.7-99.6), and negative likelihood ratio of 0.03 (95% CI: 0.00-0.18) in the validation set.

CONCLUSION

In our validation cohort of patients with acute abdominal pain, the new score can accurately predict which children are at low risk of appendicitis and could be safely managed with close observation.

Diagnostic Accuracy of Serum and Urine S100A8/A9 and Serum Amyloid A in Probable Acute Abdominal Pain at Emergency Department

Study Design

This study was performed to investigate the diagnostic values of some inflammatory biomarkers in abdominal pain.

Methods

Patients over 18 years of age with acute recent abdominal pain who presented to the Emergency Department were evaluated. Serum and urinary samples were taken and evaluated for serum and urine S100A8/A9 and serum amyloid A. All patients were referred to a surgeon and were followed up until the final diagnosis. In the end, the final diagnosis was compared with the levels of biomarkers.

Results

Of a total of 181 patients, 71 underwent surgery and 110 patients did not need surgery after they were clinically diagnosed. Mean levels of serum and urine S100A8/A9 had a significant difference between two groups, but serum amyloid A did not show. The diagnostic accuracy of serum S100A8/A9, urine S100A8/A9, and serum amyloid A was 86%, 79%, and 50%, respectively, in anticipation of the need or no need for surgery in acute abdominal pain.

Conclusions

Our study showed that in acute abdominal pain, serum and urine S100A8/A9 can be useful indicators of the need for surgery, but serum amyloid A had a low and nonsignificant diagnostic accuracy.

Seasonal variation of acute appendicitis

Objective:

To determine the seasonal variation of acute appendicitis.

Methods:

A total of 320 patients fulfilling the inclusion criteria were enrolled in the study after getting the written informed consent. Appendectomies were performed by consultant surgeons and residents. After surgery histopathological examination of specimens was performed by consultant Histopathologists at Armed Forces Institute of Pathology Rawalpindi and CMH Peshawar. The patients presenting in different four seasons September to November as autumn, December to February as winter, March to May as spring, June to August as summer, were compared to determine seasonal variations.

Results:

In our study out of all 320 patients 188 (58.75%) were males and 132 (41.25%) were females. Sixty patients (18.75 %) presented in autumn season (Sep-Nov), 52 patients (16.25%) in winter season (Dec-Feb), 78 (24.25%) patients in Spring season (Mar-May).130 (40.62%) patients presented in Summer season (Jun-Aug). There was almost 24.37% increased incidence in summer as compared to winter season, 21.87% increased incidence as compared to autumn season, 16.37% increased incidence as compared to spring season.

Conclusion:

Acute appendicitis incidence is increased in summer months in Pakistan. Preventive measures can be taken during summer season (June to Aug) to decrease morbidity and mortality associated with this disease.

Can common serum biomarkers predict complicated appendicitis in children?

PURPOSE

As appendicitis in children can be managed differently according to the severity of the disease, we investigated whether commonly used serum biomarkers on admission could distinguish between simple and complicated appendicitis.

METHODS

Admission white blood cell (WBC), neutrophil (NEU), and C-reactive protein (CRP) levels were analysed by ROC curve, and Kruskal-Wallis and contingency tests. Patients were divided according to age and histology [normal appendix (NA), simple appendicitis (SA), complicated appendicitis (CA)].

RESULTS

Of 1197 children (NA = 186, SA = 685, CA = 326), 7% were <5 years, 55% 5-12, 38% 13-17. CA patients had higher CRP and WBC levels than NA and SA (p < 0.0001). NEU levels were lower in NA compared to SA or CA (p < 0.0001), but were similar between SA and CA (p = 0.6). CA patients had higher CRP and WBC levels than SA patients in 5-12- (p < 0.0001) and 13-17-year groups (p = 0.0075, p = 0.005), but not in <5-year group (p = 0.72, p = 0.81). We found CRP >40 mg/L in 58% CA and 37% SA (p < 0.0001), and WBC >15 × 10⁹/L in 58% CA and 43% SA (p < 0.0001).

CONCLUSIONS

Admission CRP and WBC levels may help the clinician predict complicated appendicitis in children older than 5 years of age. Early distinction of appendicitis severity using these tests may guide caregivers in the preoperative decision-making process.

Diagnostic Accuracy of History, Physical Examination, Laboratory Tests, and Point-of-care Ultrasound for Pediatric Acute Appendicitis in the Emergency Department: A Systematic Review and Meta-analysis

BACKGROUND

Acute appendicitis (AA) is the most common surgical emergency in children. Accurate and timely diagnosis is crucial but challenging due to atypical presentations and the inherent difficulty of obtaining a reliable history and physical examination in younger children.

OBJECTIVES

The aim of this study was to determine the utility of history, physical examination, laboratory tests, Pediatric Appendicitis Score (PAS) and Emergency Department Point-of-Care Ultrasound (ED-POCUS) in the diagnosis of AA in ED pediatric patients. We performed a systematic review and meta-analysis and used a test-treatment threshold model to identify diagnostic findings that could rule in/out AA and obviate the need for further imaging studies, specifically computed tomography (CT) scan, magnetic resonance imaging (MRI), and radiology department ultrasound (RUS).

METHODS

We searched PubMed, EMBASE, and SCOPUS up to October 2016 for studies on ED pediatric patients with abdominal pain. Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2) was used to evaluate the quality and applicability of included studies. Positive and negative likelihood ratios (LR+ and LR-) for diagnostic modalities were calculated and when appropriate data was pooled using Meta-DiSc. Based on the available literature on the test characteristics of different imaging modalities and applying the Pauker-Kassirer method we developed a test-treatment threshold model.

RESULTS

Twenty-one studies were included encompassing 8,605 patients with weighted AA prevalence of 39.2%. Studies had variable quality using the QUADAS-2 tool with most studies at high risk of partial verification bias. We divided studies based on their inclusion criteria into two groups of "undifferentiated abdominal pain" and abdominal pain "suspected of AA." In patients with undifferentiated abdominal pain, history of "pain migration to right lower quadrant (RLQ)" (LR+ = 4.81, 95% confidence interval [CI] = 3.59-6.44) and presence of "cough/hop pain" in the physical examination (LR+ = 7.64, 95% CI = 5.94-9.83) were most strongly associated with AA. In patients suspected of AA none of the history or laboratory findings were strongly associated with AA. Rovsing's sign was the physical examination finding most strongly associated with AA (LR+ = 3.52, 95% CI = 2.65-4.68). Among different PAS cutoff points, PAS ≥ 9 (LR+ = 5.26, 95% CI = 3.34-8.29) was most associated with AA. None of the history, physical examination, laboratory tests findings, or PAS alone could rule in or rule out AA in patients with undifferentiated abdominal pain or those suspected of AA. ED-POCUS had LR+ of 9.24 (95% CI = 6.24-13.28) and LR- of 0.17 (95% CI = 0.09-0.30). Using our test-treatment threshold model, positive ED-POCUS could rule in AA without the use of CT and MRI, but negative ED-POCUS could not rule out AA.

CONCLUSION

Presence of AA is more likely in patients with undifferentiated abdominal pain migrating to the RLQ or when cough/hop pain is present in the physical examination. Once AA is suspected, no single history, physical examination, laboratory finding, or score attained on PAS can eliminate the need for imaging studies. Operating characteristics of ED-POCUS are similar to those reported for RUS in literature for diagnosis of AA. In ED patients suspected of AA, a positive ED-POCUS is diagnostic and obviates the need for CT or MRI while negative ED-POCUS is not enough to rule out AA.

Current Approach to the Diagnosis and Emergency Department Management of Appendicitis in Children

Concerns about radiation exposure have led to a decrease in the use of computed tomography in suspected appendicitis, with increased reliance on ultrasound. Children with suspected appendicitis should be risk stratified using a combination of clinical signs and symptoms, white blood cell count, and ultrasound in order to guide further evaluation and management. Magnetic resonance imaging is a promising imaging modality but remains costly. Ongoing research is evaluating the role of nonoperative management in children with confirmed appendicitis.

Diagnostic performance of a biomarker panel as a negative predictor for acute appendicitis in adult ED patients with abdominal pain

OBJECTIVES

Evaluate the diagnostic accuracy of the APPY1TM biomarker panel, previously described for use in pediatric patients, for identifying adult ED patients with abdominal pain who are at low risk of acute appendicitis.

METHODS

This study prospectively enrolled subjects >18years of age presenting to seven U.S. emergency departments with <72hours of abdominal pain suggesting possible acute appendicitis. The APPY1 panel was performed on blood samples drawn from each patient at the time of initial evaluation and results were correlated with the final diagnosis either positive or negative for acute appendicitis.

RESULTS

431 patients were enrolled with 422 completing all aspects of the study. The APPY1 biomarker panel exhibited a sensitivity of 97.5% (95% CI, 91.3-99.3%), a negative predictive value of 98.4% (95% CI, 94.4-99.6%), a negative likelihood ratio of 0.07 (95% CI, 0.02-0.27), with a specificity of 36.5% (95% CI, 31.6-41.8%) for acute appendicitis. The panel correctly identified 125 of 342 (36.6%) patients who did not have appendicitis with 2 (2.5%) false negatives. The CT utilization rate in this population was 72.7% (307/422). Of 307 CT scans, 232 were done for patients who did not have appendicitis and 79 (34%) of these patients were correctly identified as negative with "low risk" biomarker panel results, representing 26% (79/307) of all CT scans performed.

CONCLUSION

This biomarker panel exhibited high sensitivity and negative predictive value for acute appendicitis in this prospective adult cohort, thereby potentially reducing the dependence on CT for the evaluation of possible acute appendicitis.

The Influence of Age on the Diagnostic Performance of White Blood Cell Count and Absolute Neutrophil Count in Suspected Pediatric Appendicitis

OBJECTIVE

White blood cell (WBC) count and absolute neutrophil count (ANC) are a standard part of the evaluation of suspected appendicitis. Specific threshold values are utilized in clinical pathways, but the discriminatory value of WBC count and ANC may vary by age. The objective of this study was to investigate whether the diagnostic value of WBC count and ANC varies across age groups and whether diagnostic thresholds should be age-adjusted.

METHODS

This is a multicenter prospective observational study of patients aged 3-18 years who were evaluated for appendicitis. Receiver operator characteristic curves were developed to assess overall discriminative power of WBC count and ANC across three age groups: <5, 5-11, and 12-18 years of age. Diagnostic performance of WBC count and ANC was then assessed at specific cut-points.

RESULTS

A total of 2,133 patients with a median age of 10.9 years (interquartile range = 8.0-13.9 years) were studied. Forty-one percent had appendicitis. The area under the curve (AUC) for WBC count was 0.69 (95% confidence interval [CI] = 0.61 to 0.77) for patients < 5 years of age, 0.76 (95% CI = 0.73 to 0.79) for 5-11 years of age, and 0.83 (95% CI = 0.81 to 0.86) for 12-18 years of age. The AUCs for ANC across age groups mirrored WBC performance. At a commonly utilized WBC cut-point of 10,000/mm³ , the sensitivity decreased with increasing age: 95% (<5 years), 91% (5-11 years), and 89% (12-18 years) whereas specificity increased by age: 36% (<5 years), 49% (5-12 years), and 64% (12-18 years).

CONCLUSION

WBC count and ANC had better diagnostic performance with increasing age. Age-adjusted values of WBC count or ANC should be considered in diagnostic strategies for suspected pediatric appendicitis.

Acute appendicitis: transcript profiling of blood identifies promising biomarkers and potential underlying processes

Background

The diagnosis of acute appendicitis can be surprisingly difficult without computed tomography, which carries significant radiation exposure. Circulating blood cells may carry informative changes in their RNA expression profile that would signal internal infection or inflammation of the appendix.

Methods

Genome-wide expression profiling was applied to whole blood RNA of acute appendicitis patients versus patients with other abdominal disorders, in order to identify biomarkers of appendicitis. From a large cohort of emergency patients, a discovery set of patients with surgically confirmed appendicitis, or abdominal pain from other causes, was identified. RNA from whole blood was profiled by microarrays, and RNA levels were filtered by a combined fold-change (>2) and p value (<0.05). A separate set of patients, including patients with respiratory infections, was used to validate a partial least squares discriminant (PLSD) prediction model.

Results

Transcript profiling identified 37 differentially expressed genes (DEG) in appendicitis versus abdominal pain patients. The DEG list contained 3 major ontologies: infection-related, inflammation-related, and ribosomal processing. Appendicitis patients had lower level of neutrophil defensin mRNA (DEFA1,3), but higher levels of alkaline phosphatase (ALPL) and interleukin-8 receptor-ß (CXCR2/IL8RB), which was confirmed in a larger cohort of 60 patients using droplet digital PCR (ddPCR).

Conclusions

Patients with acute appendicitis have detectable changes in the mRNA expression levels of factors related to neutrophil innate defense systems. The low defensin mRNA levels suggest that appendicitis patient’s immune cells are not directly activated by pathogens, but are primed by diffusible factors in the microenvironment of the infection. The detected biomarkers are consistent with prior evidence that biofilm-forming bacteria in the appendix may be an important factor in appendicitis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12920-016-0200-y) contains supplementary material, which is available to authorized users.

Serum, Saliva, and Urine Irisin with and Without Acute Appendicitis and Abdominal Pain

A 112-amino-acid protein irisin (IRI) is widely expressed in many organs, but we currently do not know whether appendix tissue and blood cells express it. If appendix tissue and neutrophil cells express IRI, measuring its concentration in biological fluids might be helpful in the diagnosis of acute appendicitis (AA), since neutrophil cells are the currently gold-standard laboratory parameters for the diagnosis of AA. Therefore, the purpose of this study was to investigate the suitability of enzyme-linked immunosorbent assay-based measurements of the proposed myokine IRI for the discrimination of patients with AA from those with acute abdominal pain (AP) and healthy controls. Moreover, immunoreactivity to IRI was investigated in appendix tissues and blood cells. Samples were collected on admission (T1), 24 hours (T2), and 72 hours (T3) postoperatively from patients with suspected AA and from patients with AP corresponding to T1–T3, whereas control subject blood was once corresponding to T1. IRI was measured in serum, saliva, and urine by using enzyme-linked immunosorbent assay, whereas in appendix tissue and blood cells, IRI was detected by immunohistohcemistry. Appendix tissue and blood cells (except for erythrocytes) are new sources of IRI. Basal saliva, urine, and serum levels were higher in children with AA compared with postoperative levels (T2) that start to decline after surgery. This is in line with the finding that IRI levels are higher in children with AA when compared with those with AP or control subject levels, most likely due to a large infiltration of neutrophil cells in AA that release its IRI into body fluids. Measurement of IRI in children with AA parallels the increase or decrease in the neutrophil count. This new finding shows that the measurement of IRI and neutrophil count can together improve the diagnosis of AA, and it can distinguish it from AP. IRI can be a candidate marker for the diagnosis of AA and offers an additional parameter to neutrophil count. The promising receiving operating curve results indicate the following sensitivities and specificities, respectively, for IRI: serum 90% and 55%, saliva 90% and 60%, and urine 90% and 50%. Serum neutrophil count gave a sensitivity of 90% and a specificity of 90%. This promising result now needs to be confirmed in a larger group of patients.

Diagnostic value of red blood cell distribution width in pediatric acute appendicitis

BACKGROUND

The aim of this study was to evaluate the diagnostic value of red blood cell distribution width (RDW) in children with acute appendicitis.

METHODS

In this retrospective study, a total of 344 children aged ≤18 years with clinically suspected acute appendicitis who underwent appendectomy between January 2007 and January 2014 were reviewed, and 200 healthy controls of the same age group were included. Based on histopathology, the patients were classified as having normal appendix, simple or perforated appendicitis, and preoperative white blood cell count (WBC), C-reactive protein (CRP) and RDW were compared.

RESULTS

Compared with the controls, mean WBC, CRP and RDW were significantly higher in the appendectomy group (P <0.001). The children with simple or perforated appendicitis had significantly higher WBC, CRP and RDW than did those with normal appendix (P <0.001). Mean WBC and CRP were significantly higher in the children with perforated appendicitis (P <0.001), but no statistically significant difference was found in RDW between the simple and perforated appendicitis groups (P = 0.081).

CONCLUSIONS

Children with histologically proven acute appendicitis have higher RDW than children without appendicitis, but the diagnostic value of RDW was not superior to WBC or CRP in children with acute appendicitis. Although higher RDW may be valuable for aiding the diagnosis of acute appendicitis in children, it is not a useful marker for predicting perforated appendicitis.

New clinical decision instruments can and should reduce radiation exposure

In this Perspective linked to Rodriguez and colleagues, Emmanuel Lagarde discusses the importance of decision instruments that can help physicians avoid subjecting patients to radiation exposure from unnecessary CT scans.

Alarmin S100A8/S100A9 as a biomarker for molecular imaging of local inflammatory activity

Inflammation has a key role in the pathogenesis of various human diseases. The early detection, localization and monitoring of inflammation are crucial for tailoring individual therapies. However, reliable biomarkers to detect local inflammatory activities and to predict disease outcome are still missing. Alarmins, which are locally released during cellular stress, are early amplifiers of inflammation. Here, using optical molecular imaging, we demonstrate that the alarmin S100A8/S100A9 serves as a sensitive local and systemic marker for the detection of even sub-clinical disease activity in inflammatory and immunological processes like irritative and allergic contact dermatitis. In a model of collagen-induced arthritis, we use S100A8/S100A9 imaging to predict the development of disease activity. Furthermore, S100A8/S100A9 can act as a very early and sensitive biomarker in experimental leishmaniasis for phagocyte activation linked to an effective Th1-response. In conclusion, the alarmin S100A8/S100A9 is a valuable and sensitive molecular target for novel imaging approaches to monitor clinically relevant inflammatory disorders on a molecular level.