Advancements in the diagnosis of acute appendicitis in children and adolescents

Accuracy of point-of-care ultrasound in the diagnosis of acute appendicitis in a pediatric emergency department

PURPOSE

To investigate the accuracy of point-of-care ultrasound (PoCUS) in diagnosing acute appendicitis in children; to evaluate the concordance between PoCUS performed by a pediatric emergency physician (PedEm) and ultrasonography (US) performed by a radiologist; to draw a "learning curve."

METHODS

We prospectively enrolled children aged 0-14 years old led to the Emergency Department of Regina Margherita Children's Hospital, from January 2021 to June 2021, with suspected acute appendicitis. PoCUS was performed by a single trained PedEm, blindly to the radiologist's scan. A "self-assessment score" and the "time of duration of PoCUS" were recorded for each patient. Final diagnosis of appendicitis was made by a pediatric surgeon.

RESULTS

We enrolled 62 children (2-14 years). Overall sensitivity of PoCUS was 88%, specificity 90%; PPV 90.6%, and NPV 86.6%. Global concordance between the PedEm and the radiologist was good/excellent (k 0.74). The mean duration of PoCUS significantly decreased during the study period, while the self-assessment score increased.

CONCLUSION

This is a preliminary study that shows the effectiveness of PoCUS in diagnosing acute appendicitis; furthermore, it shows how the PedEm's performance may improve over time. The learning curve showed how the experience of the PedEm affects the accuracy of PoCUS.

Is Ischemia-Modified Albumin a Reliable Marker in Accurate Diagnosis of Appendicitis in Children?

BACKGROUND

Acute appendicitis is one of the most common abdominal emergencies. Despite all improvements in diagnostic techniques, there are still ongoing problems as proper diagnosis, misdiagnosis and perforated appendicitis. The aim of this study is to demonstrate the clinical value of IMA in patients with appendicitis and to determine the accurate diagnosis of appendicitis in clinically suspected patients.

METHODS

Pediatric patients with acute abdominal pain who had the Pediatric Appendicitis Score (PAS) ≥ 7 (n = 109) and a control group of 35 patients were included in this prospective case-control study. Patients were divided into two groups: patients with appendicitis (pathologically confirmed) (n = 78) and no appendicitis (n = 31). No appendicitis included observation patients and negative appendectomy. Serum samples were collected for routine laboratory parameters and IMA before surgery.

RESULTS

Patients with appendicitis had significantly higher IMA levels than no appendicitis and control groups (p = 0.001 and p < 0.001; respectively). Moreover, patients with negative appendectomy had significantly lower IMA levels than patients with appendicitis (p = 0.009). IMA and PAS were used together, and in the ROC analysis, we obtained 0.81 AUC for PAS and 0.89 AUC for PAS and IMA.

CONCLUSION

The current study indicated that IMA is a reliable marker for accurate diagnosis of appendicitis. The combination of IMA with PAS score has been shown to facilitate the diagnosis of appendicitis.

Diagnostic accuracy of procalcitonin for overall and complicated acute appendicitis in children: a meta-analysis

Background

Diagnostic value of procalcitonin (PCT) for acute appendicitis (AA) has been evaluated in adult patients, but the application in children remains controversial. The aim of this study was to evaluate the diagnostic value of PCT for overall and complicated AA in children.

Methods

The PubMed, EMBASE, Web of Science, Cochrane Database of Systematic Reviews, Chinese National Knowledge Infrastructure, and Wanfang were searched along with reference lists of relevant articles up to January 2018 without language restrictions. Original articles that reported the performance of PCT in the diagnosis of pediatric AA and associated complications were selected. To assess the diagnostic value of PCT, sensitivity, specificity, diagnostic odds ratios (DORs), summary receiver operating characteristic (ROC) curves, area under the curve (AUC), and 95% confidence intervals (95% CIs) were estimated.

Results

Seven qualifying studies (504 confirmed AA and 368 controls) from 6 countries for overall AA and 4 studies (187 complicated AA and 185 uncomplicated AA) for complicated AA from 3 countries were identified. The pooled sensitivity and specificity of PCT for the diagnosis of pediatric AA were 0.62 (95% CI: 0.57–0.66) and 0.86 (95% CI: 0.82–0.89), respectively. The DOR was 21.4 (95% CI: 3.64–126.1) and the AUC was 0.955. PCT was more accurate in diagnosing complicated appendicitis, with a pooled sensitivity of 0.89 (95% CI: 0.84–0.93), specificity of 0.90 (95% CI: 0.86–0.94), and DOR of 76.73 (95% CI: 21.6–272.9).

Conclusion

This meta-analysis showed that PCT may have potential value in diagnosing pediatric AA. Moreover, PCT had greater diagnostic value in identifying pediatric complicated appendicitis.

Cytokines and Chemokines in Pediatric Appendicitis: A Multiplex Analysis of Inflammatory Protein Mediators

OBJECTIVES

We aimed to demonstrate the potential of precision medicine to describe the inflammatory landscape present in children with suspected appendicitis. Our primary objective was to determine levels of seven inflammatory protein mediators previously associated with intra-abdominal inflammation (C-reactive protein-CRP, procalcitonin-PCT, interleukin-6 (IL), IL-8, IL-10, monocyte chemoattractant protein-1-MCP-1, and serum amyloid A-SAA) in a cohort of children with suspected appendicitis. Subsequently, using a multiplex proteomics approach, we examined an expansive array of novel candidate cytokine and chemokines within this population.

METHODS

We performed a secondary analysis of targeted proteomics data from Alberta Sepsis Network studies. Plasma mediator levels, analyzed by Luminex multiplex assays, were evaluated in children aged 5-17 years with nonappendicitis abdominal pain (NAAP), acute appendicitis (AA), and nonappendicitis sepsis (NAS). We used multivariate regression analysis to evaluate the seven target proteins, followed by decision tree and heat mapping analyses for all proteins evaluated.

RESULTS

185 children were included: 83 with NAAP, 79 AA, and 23 NAS. Plasma levels of IL-6, CRP, MCP-1, PCT, and SAA were significantly different in children with AA compared to those with NAAP (p < 0.001). Expansive proteomic analysis demonstrated 6 patterns in inflammatory mediator profiles based on severity of illness. A decision tree incorporating the proteins CRP, ferritin, SAA, regulated on activation normal T-cell expressed and secreted (RANTES), monokine induced by gamma interferon (MIG), and PCT demonstrated excellent specificity (0.920) and negative predictive value (0.882) for children with appendicitis.

CONCLUSIONS

Multiplex proteomic analyses described the inflammatory landscape of children presenting to the ED with suspected appendicitis. We have demonstrated the feasibility of this approach to identify potential novel candidate cytokines/chemokine patterns associated with a specific illness (appendicitis) amongst those with a broad ED presentation (abdominal pain). This approach can be modelled for future research initiatives in pediatric emergency medicine.

Delaying laparoscopic surgery in pregnant patients with an equivocal acute appendicitis: a step-wise approach does not affect maternal or fetal safety

BACKGROUND

Accurate and timely diagnoses of acute appendicitis (AA) during pregnancy avoids maternal and fetal morbidity and mortality. We present our experience of using an initial transabdominal ultrasound (US) performed at presentation to diagnose AA in pregnant patients as well as the value of a delayed repeat study in those who remain equivocal. We explore the sensitivity and specificity of this algorithm as well as the maternal and fetal safety of this approach.

METHODS

Of the 225 patients identified within the study period who underwent laparoscopic appendectomy, 216 met the inclusion criteria and were retrospectively analyzed. If the US performed on presentation revealed AA, surgery was performed. Patients with a non-diagnostic US were admitted with surgery performed if there was clinical and/or biochemical deterioration. Patients who remained equivocal underwent a repeat delayed study. The results of the initial versus delayed studies were compared. Maternal and fetal complications were recorded and contrasted.

RESULTS

Of the 216 patients included, 164 (75.9%) had AA, 14 (6.5%) had complicated AA and 38 (17.6%) had a normal appendix. Initial US was diagnostic for 125/216 (57.9%) of patients and 19/34 (55.8%) of patients who underwent a delayed repeat study. The remaining patients underwent empirical surgery. The pooled sensitivity and specificity of US for the cohort was 79.2% and 92.1%, respectively. There was no difference in proxies of maternal or fetal safety between the groups.

CONCLUSION

US is a useful tool for diagnosing AA in pregnancy. In this cohort, performing a delayed repeat US during a period of observation in those patients who remained otherwise equivocal increased the diagnostic yield of the US. Delaying surgery in this specific group of patients does not affect maternal or fetal safety.

Polymorphisms in the IL-6 and IL-6R receptor genes as new diagnostic biomarkers of acute appendicitis: a study on two candidate genes in pediatric patients with acute appendicitis

Background

Acute appendicitis (AA) (OMIM: 107700) is an inflammatory disease which is characterized by appendiceal inflammation. Genetic and environmental factors contribute to the development of AA. Especially, multiple genetic factors appear to be promising in the explanation of etiopathogenesis of AA. IL-6 (Interleukin-6) is an inflammatory cytokine and IL-6 receptor (IL-6R) plays an important role in the immune response. IL-6 (-572G/C rs1800796) and IL-6R (1:G.154448302 T > C rs7529229) gene polymorphisms may have an impact on cytokine production, immune response and these gene polymorphisms may be used as inflammatory markers in the diagnosis of appendicitis.

Method

A total of 75 children with appendicitis, and 75 healthy children were included in the study. DNA extracts were obtained from peripheral lymphocytes. Single-nucleotide polymorphisms (SNPs) were analysed using an automated SYBR® Green RT-PCR system in pediatric patients with appendicitis (n = 75) and healthy controls (n = 75).

Results

The allele and genotype frequencies for IL-6 rs1800796 and IL-6R rs7529229 polymorphisms were not different between the study groups (p > 0.05). Any statistically significant differences as for age, sex and other laboratory factors were not detected between the patients with appendicitis for genotype-allele frequencies (p > 0.05). Still in analyses performed to determine correlations among age, and gender of the patients, routine laboratory parameters and allele-genotype frequencies, a statistically significant intergroup difference was not detected. Genotype and allele frequencies were consistent with Hardy-Weinberg equilibrium (HWE) in all groups.

Discussion

This is the first study to investigate the effects of functional two polymorphisms on IL-6 and IL-6R genes in a pediatric patient group with AA risk. With this study we investigated the contribution of IL-6 (-572G/C rs1800796) and IL-6R (1:G.154448302 T > C rs7529229) polymorphisms on pathogenesis, and severity of AA in pediatric patients with AA: These results will guide further genetic researches to be performed on the role of IL-6 and IL-6R in AA.

Conclusions

Given the putative biological importance of this SNPs, these emerging data can provide a new foundation to stimulate future debate and genetic investigations of AA, focusing on new molecular mechanisms such as other IL gene polymorphisms, particularly in accessible peripheral tissues for novel molecular diagnostics for appendicitis.

Admission levels of serum amyloid a and procalcitonin are more predictive of the diagnosis of acute appendicitis compared with C-reactive protein

BACKGROUND

Acute appendicitis is the commonest surgical emergency, but its diagnosis can be elusive with a negative appendicectomy rate of 20%. The aims of this study were to investigate the potential value of the markers of acute inflammation, serum amyloid A (SAA), and serum procalcitonin (ProCT), in the diagnosis of acute appendicitis in adults and to compare that with the commonly used serum C-reactive protein (CRP).

METHODS

Adult patients presenting with acute right lower abdominal pain and a clinical suspicion of acute appendicitis were included. Blood samples were obtained within 6 hours of admission for rapid serum CRP assay and for end-of-recruitment batch analysis of SAA and serum ProCT concentrations.

RESULTS

A total of 147 patients (81 males) with a mean (±SD) age of 36 (±17) years were recruited. Appendicitis was confirmed histologically in 61 of 72 patients (84.7%) who underwent appendicectomy. A post hoc analysis revealed a diagnostic sensitivity and specificity for SAA of 92% and 72%, ProCT of 85% and 74%, and CRP of 75% and 72%, respectively. The receiver operator characteristics for the area under the curves showed that SAA (P=0.011) and ProCT (P=0.037) significantly exceeded CRP in the prediction of acute appendicitis on admission.

CONCLUSIONS

The measurement of SAA and serum ProCT on admission in patients with clinically suspected acute appendicitis seems to outperform serum CRP in aiding that diagnosis.

Role of mean platelet volume in diagnosis of childhood acute appendicitis

Introduction. Acute appendicitis is the leading cause of abdominal pain in children requiring emergency surgical intervention. The aim of this study is to investigate the diagnostic value of MPV in early diagnosis of acute appendicitis cases in pediatric age group. Methods. This study was performed retrospectively. Three hundred five patients operated on with the diagnosis of appendicitis and pathologically found to be acute appendicitis were classified as Group 1 and 305 healthy children were classified as control Group 2. Results. One hundred ninety-seven of 305 cases in Group 1 are males (64.6%), in Group 2, 151 of 305 cases are males (49.5%). The mean MPV in Group 1 was 7.9 ± 0.9 (fL), and whereas in Group 2 was 7.7 ± 0.8 (fL). There was no statistically significant difference regarding MPV values (P > 0.05). Conclusion. In our study we detected that mean platelet volume has no diagnostic value in pediatric acute appendicitis cases.

C-reactive protein and procalcitonin are predictors of the severity of acute appendicitis in children

OBJECTIVE

The aim of this study was to evaluate the use of procalcitonin (PCT) and C-reactive protein (CRP) on admission as predictors of the severity of appendicitis in children.

METHODS

We prospectively studied 111 consecutive patients admitted with a diagnosis of acute appendicitis between July 2009 and February 2010 and recorded the following variables: age, sex, time since diagnosis, laboratory data, complications (abscess, intestinal obstruction), presence of hemodynamic instability, mortality, length of stay, and need for admission to the pediatric intensive care unit. Patients were divided into 2 groups according to the diagnosis confirmed during surgery (group 1, appendicitis; group 2, localized or generalized peritonitis).

RESULTS

Group 1 comprised 69 patients, and group 2 comprised 42 patients. Procalcitonin and CRP values were significantly lower in group 1 than in group 2 (0.15 vs 4.95 ng/mL [P < 0.001] and 3 vs 14.3 mg/dL [P < 0.001]). For a diagnosis of peritonitis, a PCT cutoff of 0.18 ng/mL gave a sensitivity of 97%, specificity of 80%, positive predictive value of 72%, and negative predictive value of 89.3%. The equivalent values for a CRP cutoff of 3 mg/dL were 95%, 74%, 68%, and 96.2%. Complications and the need for admission to the pediatric intensive care unit were more common in patients with peritonitis.

CONCLUSIONS

On admission, CRP and PCT predict the outcome of pediatric patients with appendicitis. Children with CRP greater than 3 mg/dL and/or PCT greater than 0.18 ng/mL have a greater risk of complications; thus, intervention should be early, and patients should be monitored closely.

Procalcitonin as a marker of severe bacterial infection in children in the emergency department

Procalcitonin, the prohormone of calcitonin, is a relatively new and innovative marker of bacterial infection that has multiple potential applications in the pediatric emergency department. In healthy individuals, circulating levels of procalcitonin are generally very low (<0.05 ng/mL), but in the setting of severe bacterial infection and sepsis, levels can increase by hundreds to thousands of fold within 4 to 6 hours. Although the exact physiologic function of procalcitonin has not been determined, the consistent response and rapid rise of this protein in the setting of severe bacterial infection make procalcitonin a very useful biomarker for invasive bacterial disease. In Europe, serum procalcitonin measurements are frequently used in the diagnosis and the management of patients in a variety of clinical settings. To date, the use of procalcitonin has been limited in the United States, but this valuable biomarker has many potential applications in both the pediatric emergency department and the intensive care unit. The intent of this article is to review the history of procalcitonin, describe the kinetics of the molecule in response to bacterial infection, describe the laboratory methods available for measuring procalcitonin, examine the main causes of procalcitonin elevation, and evaluate the potential applications of procalcitonin measurements in pediatric patients.

A prospective bicenter study investigating the diagnostic value of procalcitonin in patients with acute appendicitis

BACKGROUND

Procalcitonin (PCT) is an established laboratory marker for disease severity in patients with infection and sepsis. In addition, PCT has been shown to be an effective marker for a limited number of localized infections. However, whether or not PCT has any diagnostic value for acute appendicitis, still remains unclear. The purpose of this prospective bicenter study was, therefore, to determine whether or not the PCT levels in the serum of patients with acute appendicitis have any diagnostic value.

METHODS

This prospective study included 103 patients who received an appendectomy, based on the clinical diagnosis of acute appendicitis, in a surgical department of an academic teaching hospital in Germany or in a county hospital in Spain. White blood cell count (WBC), C-reactive protein (CRP) and procalcitonin (PCT) values were determined preoperatively. All appendectomy specimens were sent for routine histopathological evaluation. Based on this information, the patients were assigned to 1 of 5 groups that reflected the severity of the appendicitis.

RESULTS

Of the 103 patients who were included in the study, 98 had appendicitis. Fourteen (14.3%) showed an increase in PCT values. Of those 14, 4 had a serum PCT >0.5 ng/ml, 9 had a PCT value >2-10 ng/ml and 1 had a PCT value >10 ng/ml. The sensitivity of PCT was calculated to be 0.14. The mean WBC value was 13.0/nl (+/- 5.2, 3.4-31), and for CRP it was 8.8 mg/dl (+/- 13, 0-60.2). The values of CRP, WBC and PCT increased with the severity of the appendicitis.

CONCLUSIONS

PCT is potentially increased in rare cases of severe inflammation and, in particular, after appendiceal perforation or gangrenous appendicitis. However, its remarkably low sensitivity prohibits its routine use for the diagnosis of appendicitis.

Pelvic osteomyelitis: a diagnostic challenge in children

BACKGROUND

Acute hematogenous osteomyelitis (AHOM) in children usually occurs in tubular bones. Acute hematogenous osteomyelitis of the pelvis is rare and is often not recognized primarily.

METHODS

To review the experience with pelvic AHOM at our institution, we analyzed records from children diagnosed with pelvic AHOM (1984-2003) and compared with those reported in the literature.

RESULTS

Among 220 children with AHOM (median age, 6.4 years), those 19 (9%) with pelvic AHOM were significantly older (median age, 9.0 years; range, 0.04-15.6). All children presented with limping or refused to walk. Twelve of 19 patients were febrile, 16 of 18 had elevated C-reactive protein (>20 mg/L), and 6 of 19 had leukocytes greater than 12 G/L. Staphylococcus aureus was isolated from blood or bone aspirates in 9 of 17 patients, and Streptococcus pneumoniae was isolated in 1. Scintigraphy was diagnostic in 15 of 15 children, and magnetic resonance imaging in 7 of 7 children. The mean time between initial symptoms and diagnosis was 3 days (range, 1-8 days). Infection resolved completely in all children after antibiotic therapy.

CONCLUSION

Pelvic AHOM should be considered in children with limping and pain referred to the hip, thigh, or abdomen. Diagnosis by scintigraphy or magnetic resonance imaging followed by local puncture and microbiological workup allows for specific antibiotic treatment and results in an excellent outcome of pelvic AHOM.

Harmonic US imaging of appendicitis in children

BACKGROUND

Harmonic imaging (HI), a relatively new ultrasound modality, was initially reported to be of use only in obese adult patients. HI increases the contrast and spatial resolution resulting in artefact-free images, and has been shown in adults to significantly improve abdominal sonography. Regarding its application in paediatric patients, just a handful reports exist and these do not encompass its use in intestinal sonography.

OBJECTIVE

To compare the sonomorphological image quality of HI and fundamental imaging (FI, conventional grey-scale imaging) in the diagnosis of histologically confirmed appendicitis in children.

MATERIALS AND METHODS

For this prospective comparative study, 50 children (male/female 25/25; mean age 9.9 years) suspected of having appendicitis were recruited. In all patients US examination of the appendix and periappendiceal region was performed preoperatively and appendectomy carried out. The final diagnosis was based on histological examination of the appendix. Both FI and HI were used in the US examination (tissue harmonic imaging, THI; Sonoline Elegra, Siemens; 7.5 MHz linear transducer). A detailed comparison of the images from FI and HI was performed using a scoring system. The parameters compared included delineation of the appendiceal contour, wall, mucosa, contents of the appendix and surrounding tissues. Furthermore, periappendiceal findings such as mesenteric echogenicity, free fluid, lymph nodes and adjacent bowel wall thickening were compared.

RESULTS

In 43 children (86%) acute appendicitis was histologically confirmed. The inflamed appendix could be depicted in the HI and FI modes in 93% and 86%, respectively. HI was found to be significantly better for the depiction of the outer contour, wall, mucosa and contents of the appendix (P<0.01). This was also true for the demonstration of free fluid, mesenteric lymph nodes, adjacent bowel walls and mesenteric echogenicity.

CONCLUSION

HI should be the preferred modality for scanning the right lower abdomen in suspected acute appendicitis. The diagnosis of acute appendicitis can then be more definitely ascertained.

[Procalcitonin measurement in adult clinical practice]

PURPOSE

The availability of a sensitive, specific and prognostic marker of bacterial infection is a major issue. More than ten years after the first publication assessing the usefulness of serum procalcitonin dosage (PCT), its exact place in the diagnostic process remained to be defined. The purpose of this review is to point out the indications of PCT measurement in clinical practice in the adult population.

RELEVANT DATA

PCT is an early, sensitive but above all specific marker of severe bacterial/parasitic infections. After being studied mostly in critically ill patients, the indications of PCT measurement have been extended to medical and emergency medicine practice, generating cut-off points between 0.2 and 0.6 microg/L. The medical area of application of PCT measurement is varied: discrimination between inflammatory disease and infectious complication or between bacterial/parasitic and viral infection, diagnosis of negative result gram staining meningitis or shock, assessment of antibiotic treatment efficiency. Moreover, PCT measurement provides outcome information in that sepsis-related raised PCT levels seem to be closely related to the magnitude of host systemic inflammatory response to microbial invasion. High PCT levels allow the early identification of patients prone to develop severe sepsis or septic shock.

PROSPECTS

After the first published study reporting the usefulness of PCT as a screening biological tool in emergency medicine, future studies will probably refined the place of PCT in such practice fields: decision about inpatient or outpatient management or antibiotics dispensation. Finally, PCT measurement could help physician in screening which septic patients should benefit from sepsis innovative therapeutics.

Procalcitonin as a predictor of severe appendicitis in children

The aim of this study was to assess the diagnostic value of procalcitonin (PCT) in 212 children with appendicitis and compare it with that of the standard diagnostic modalities, C-reactive protein (CRP) level, leukocyte count, and abdominal ultrasound findings, in relation to the surgical and histological findings of the appendix. A PCT value of >0.5 ng/ml was found to be indicative of perforation or gangrene with 73.4% sensitivity and 94.6% specificity, a CRP level of >50 mg/l and a leukocyte count of >10(4)/mm3 were useful diagnostic markers for perforation, while abdominal ultrasonography had a sensitivity of 82.8% and a specificity of 91.2% for detecting appendicitis with imaging findings. PCT measurement seems to be a useful adjunctive tool for diagnosing acute necrotizing appendicitis or perforation, and surgical exploration will probably be required in patients with PCT values >0.5 ng/ml.

A clinical decision rule to identify children at low risk for appendicitis

OBJECTIVE

Computed tomography (CT) has gained widespread acceptance in the evaluation of children with suspected appendicitis. Concern has been raised regarding the long-term effects of ionizing radiation. Other means of diagnosing appendicitis, such as clinical scores, are lacking in children. We sought to develop a clinical decision rule to predict which children with acute abdominal pain do not have appendicitis.

METHODS

Prospective cohort study was conducted of children and adolescents who aged 3 to 18 years, had signs and symptoms suspicious for appendicitis, and presented to the emergency department between April 2003 and July 2004. Standardized data-collection forms were completed on eligible patients. Two low-risk clinical decision rules were created and validated using logistic regression and recursive partitioning. The sensitivity, negative predictive value (NPV), and negative likelihood ratio of each clinical rule were compared.

RESULTS

A total of 601 patients were enrolled. Using logistic regression, we created a 6-part score that consisted of nausea (2 points), history of focal right lower quadrant pain (2 points), migration of pain (1 point), difficulty walking (1 point), rebound tenderness/pain with percussion (2 points), and absolute neutrophil count of >6.75 x 10(3)/microL (6 points). A score < or =5 had a sensitivity of 96.3% (95% confidence interval [CI]: 87.5-99.0), NPV of 95.6% (95% CI: 90.8-99.0), and negative likelihood ratio of .102 (95% CI: 0.026-0.405) in the validation set. Using recursive partitioning, a second low-risk decision rule was developed consisting of absolute neutrophil count of <6.75 x 10(3)/microL, absence of nausea, and absence of maximal tenderness in the right lower quadrant. This rule had a sensitivity of 98.1% (95% CI: 90.1-99.9), NPV of 97.5% (95% CI: 86.8-99.9), and negative likelihood ratio of 0.058 (95% CI: 0.008-0.411) in the validation set. Theoretical application of the low-risk rules would have resulted in a 20% reduction in CT.

CONCLUSIONS

Our low-risk decision rules can predict accurately which children are at low risk for appendicitis and could be treated safely with careful observation rather than CT examination.