The utility of unenhanced computed tomography in appendicitis in children

ACR Appropriateness Criteria® Suspected Appendicitis-Child

Acute appendicitis represents the most common abdominal surgical urgency/emergency in children. Imaging remains a central tool in the diagnosis of acute appendicitis and has been shown to facilitate management and decrease the rate of negative appendectomies. The initial consideration for imaging in a child with suspected acute appendicitis is based on clinical assessment, which can be facilitated with published scoring systems. The level of clinical risk (low, intermediate, high) and the clinical scenario (suspicion for complication) define the need for imaging and the optimal imaging modality. In some situations, no imaging is required, while in others ultrasound, CT, or MRI may be appropriate. This review frames the presentation of suspected acute appendicitis in terms of the clinical risk and also discusses the unique situations of the equivocal or nondiagnostic initial ultrasound examination and suspected appendicitis with suspicion for complication (eg, bowel obstruction). The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Usefulness of the pediatric appendicitis score for assessing the severity of acute appendicitis in children

BACKGROUND

We investigated relationships between the Pediatric Appendicitis Score (PAS) and pathological progression and disease severity in pediatric acute appendicitis.

METHODS

We retrospectively evaluated 72 children who underwent surgery for acute appendicitis. We divided them into groups: simple appendicitis (n = 28) or complicated appendicitis (n = 44). We compared the influence of age, body temperature, blood test findings, hospitalization period, number of complications, and PAS between the groups. We calculated the sensitivity, specificity, positive predictive value, and negative predictive value of the PAS for diagnosing complicated appendicitis. A receiver operating characteristic curve was constructed to evaluate the cut-off value for diagnosing complicated appendicitis. To assess the severity of acute appendicitis, we divided the patients into groups according to that cut-off value.

RESULTS

There were statistically significant differences in the PAS between simple appendicitis and complicated appendicitis (5.8 versus 7.9). The receiver operating characteristic curve indicated a PAS cut-off value of 8. A PAS ≥ 8 had a sensitivity of 73%, a specificity of 89%, a positive predictive value of 91%, and a negative predictive value of 68%. A PAS ≥ 8 was associated with significantly longer hospitalization and more complications than a PAS < 8.

CONCLUSIONS

The PAS may be associated with pathological progression and disease severity in appendicitis.

Computed tomography for diagnosis of acute appendicitis in adults

BACKGROUND

Diagnosing acute appendicitis (appendicitis) based on clinical evaluation, blood testing, and urinalysis can be difficult. Therefore, in persons with suspected appendicitis, abdominopelvic computed tomography (CT) is often used as an add-on test following the initial evaluation to reduce remaining diagnostic uncertainty. The aim of using CT is to assist the clinician in discriminating between persons who need surgery with appendicectomy and persons who do not.

OBJECTIVES

Primary objective Our primary objective was to evaluate the accuracy of CT for diagnosing appendicitis in adults with suspected appendicitis. Secondary objectives Our secondary objectives were to compare the accuracy of contrast-enhanced versus non-contrast-enhanced CT, to compare the accuracy of low-dose versus standard-dose CT, and to explore the influence of CT-scanner generation, radiologist experience, degree of clinical suspicion of appendicitis, and aspects of methodological quality on diagnostic accuracy.

SEARCH METHODS

We searched MEDLINE, Embase, and Science Citation Index until 16 June 2017. We also searched references lists. We did not exclude studies on the basis of language or publication status.

SELECTION CRITERIA

We included prospective studies that compared results of CT versus outcomes of a reference standard in adults (> 14 years of age) with suspected appendicitis. We excluded studies recruiting only pregnant women; studies in persons with abdominal pain at any location and with no particular suspicion of appendicitis; studies in which all participants had undergone ultrasonography (US) before CT and the decision to perform CT depended on the US outcome; studies using a case-control design; studies with fewer than 10 participants; and studies that did not report the numbers of true-positives, false-positives, false-negatives, and true-negatives. Two review authors independently screened and selected studies for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently collected the data from each study and evaluated methodological quality according to the Quality Assessment of Studies of Diagnostic Accuracy - Revised (QUADAS-2) tool. We used the bivariate random-effects model to obtain summary estimates of sensitivity and specificity.

MAIN RESULTS

We identified 64 studies including 71 separate study populations with a total of 10,280 participants (4583 with and 5697 without acute appendicitis). Estimates of sensitivity ranged from 0.72 to 1.0 and estimates of specificity ranged from 0.5 to 1.0 across the 71 study populations. Summary sensitivity was 0.95 (95% confidence interval (CI) 0.93 to 0.96), and summary specificity was 0.94 (95% CI 0.92 to 0.95). At the median prevalence of appendicitis (0.43), the probability of having appendicitis following a positive CT result was 0.92 (95% CI 0.90 to 0.94), and the probability of having appendicitis following a negative CT result was 0.04 (95% CI 0.03 to 0.05). In subgroup analyses according to contrast enhancement, summary sensitivity was higher for CT with intravenous contrast (0.96, 95% CI 0.92 to 0.98), CT with rectal contrast (0.97, 95% CI 0.93 to 0.99), and CT with intravenous and oral contrast enhancement (0.96, 95% CI 0.93 to 0.98) than for unenhanced CT (0.91, 95% CI 0.87 to 0.93). Summary sensitivity of CT with oral contrast enhancement (0.89, 95% CI 0.81 to 0.94) and unenhanced CT was similar. Results show practically no differences in summary specificity, which varied from 0.93 (95% CI 0.90 to 0.95) to 0.95 (95% CI 0.90 to 0.98) between subgroups. Summary sensitivity for low-dose CT (0.94, 95% 0.90 to 0.97) was similar to summary sensitivity for standard-dose or unspecified-dose CT (0.95, 95% 0.93 to 0.96); summary specificity did not differ between low-dose and standard-dose or unspecified-dose CT. No studies had high methodological quality as evaluated by the QUADAS-2 tool. Major methodological problems were poor reference standards and partial verification primarily due to inadequate and incomplete follow-up in persons who did not have surgery.

AUTHORS' CONCLUSIONS

The sensitivity and specificity of CT for diagnosing appendicitis in adults are high. Unenhanced standard-dose CT appears to have lower sensitivity than standard-dose CT with intravenous, rectal, or oral and intravenous contrast enhancement. Use of different types of contrast enhancement or no enhancement does not appear to affect specificity. Differences in sensitivity and specificity between low-dose and standard-dose CT appear to be negligible. The results of this review should be interpreted with caution for two reasons. First, these results are based on studies of low methodological quality. Second, the comparisons between types of contrast enhancement and radiation dose may be unreliable because they are based on indirect comparisons that may be confounded by other factors.

Diagnostic performance of CT for pediatric patients with suspected appendicitis in various clinical settings: a systematic review and meta-analysis

OBJECTIVE

To assess the diagnostic performance of CT for pediatric patients with suspected appendicitis in various clinical settings and the proportion of acute appendicitis on final diagnosis among equivocal CT findings.

METHODS

MEDLINE and EMBASE databases were searched until October 21, 2017, for studies investigating diagnostic performance of CT for acute appendicitis in pediatric patients confirmed by histopathologic findings and/or clinical follow-up. Pooled estimates of sensitivity and specificity were calculated using a hierarchical logistic regression modeling. The proportion of true appendicitis among patients with inconclusive CT results was obtained using fixed and random effects meta-analyses.

RESULTS

Twenty-two articles with 3396 patients were included. The pooled sensitivity and specificity were 95% (95% CI, 93-97%) and 94% (95% CI, 90-96%), respectively, and the area under the hierarchical summary receiver operating characteristic (HSROC) curve was 0.98 (95% CI, 0.96-0.99). Subgroup analyses revealed a comparable diagnostic performance in the low-dose CT group (sensitivity, 97%; specificity, 96%) and the unenhanced group (sensitivity, 95%; specificity, 95%). Other subgroups (publication year, study design, enrolled population, true appendicitis proportion, CT channel number, and slice thickness) also showed good diagnostic performance. Six studies reporting the true appendicitis proportion among patients with equivocal CT findings had pooled proportion of 17% (95% CI, 9-29%).

CONCLUSIONS

CT showed good performance for suspected appendicitis in pediatric patients under various clinical settings, including in cases with dose reduction or absence of IV contrast. The prevalence of true appendicitis among patients with equivocal appendicitis results on CTs was not low; therefore, clinical attention should not be disregarded in this population.

Ultrasound, computed tomography or magnetic resonance imaging - which is preferred for acute appendicitis in children? A Meta-analysis

BACKGROUND

There is no established consensus about the relative accuracies of US, CT and MRI in childhood appendicitis.

OBJECTIVE

To compare, through meta-analysis, the accuracies of US, CT and MRI for clinically suspected acute appendicitis in children.

MATERIALS AND METHODS

PubMed, Embase, Web of Science and the Cochrane Library were searched. After study selection, data extraction and quality assessment, the sensitivity, specificity and the area under the curve of summary receiver operating characteristic were calculated and compared.

RESULTS

Twenty-seven articles including 29 studies met the inclusion criteria, including 19 studies (9,170 patients) of US, 6 studies (928 patients) of CT and 4 studies (990 patients) of MRI. The analysis showed that the area under the receiver operator characteristics curve of MRI (0.995) was a little higher than that of US (0.987) and CT (0.982; P > 0.05).

CONCLUSION

US, CT and MRI have high diagnostic accuracies of clinically suspected acute appendicitis in children overall with no significant difference.

Pediatric appendicitis: pathophysiology and appropriate use of diagnostic imaging

Evaluating children for appendicitis can be extremely difficult, and various strategies have been developed to improve the precision of preoperative diagnosis. Among these, ultrasound and computed tomography (CT) are now widely used but remain controversial. Although CT scanning is superior to ultrasound in terms of diagnostic accuracy for appendicitis, the large dose of ionizing radiation from CT and the risk of subsequent radiation-induced malignancy (RIM) are of particular concern in pediatric patients. This article reviews the literature on the pathophysiology, morbidity and mortality of appendicitis, summarizes the data regarding pediatric imaging in appendicitis, provides a practical approach to imaging for clinicians who evaluate pediatric patients, and makes recommendations for reducing the risk of RIM in pediatric patients.

Paediatric GI emergencies

Paediatric GI emergencies constitute a wide range of gut pathologies ranging from those that are common, easily diagnosed and treated to conditions that are rarer, often more severe and challenging to manage. Among a myriad of ordinary clinical symptoms and signs physicians have to identify the child with a serious, life-threatening pathology and initiate the appropriate diagnostic and therapeutic pathway. The aim of the review is to present and discuss a selection of key paediatric GI emergencies that provide challenges in diagnosis and treatment. These conditions are classified by their presentation or pathogenesis and include inflammatory conditions, those presenting with GI obstruction or haemorrhage and the ingestion of foreign bodies or caustic substances. The most recent advances regarding the management of these entities are discussed along with key areas of clinical practice and future research.

Abdominal pain in children

Abdominal pain is one of the most common reasons pediatric patients seek emergency care. The emergency physician must be able to distinguish diagnoses requiring immediate attention from self-limiting processes. Pediatric patients can be challenging, particularly those who are preverbal, and therefore, the clinician must rely on a detailed history from a parent or caregiver as well as a careful physical examination in order to narrow the differential diagnosis. This article highlights several pediatric diagnoses presenting as abdominal pain, including surgical emergencies, nonsurgical diagnoses, and extraabdominal processes, and reviews the clinical presentation, diagnostic evaluation, and management of each.

Clinical policy: Critical issues in the evaluation and management of emergency department patients with suspected appendicitis

This clinical policy from the American College of Emergency Physicians is an update of a 2000 clinical policy on the evaluation and management of patients presenting with nontraumatic acute abdominal pain.1 A writing subcommittee reviewed the literature to derive evidence-based recommendations to help clinicians answer the following critical questions: (1)Can clinical findings be used to guide decision making in the risk stratification of patients with possible appendicitis? (2) In adult patients with suspected acute appendicitis who are undergoing a computed tomography scan, what is the role of contrast? (3) In children with suspected acute appendicitis who undergo diagnostic imaging, what are the roles of computed tomography and ultrasound in diagnosing acute appendicitis?Evidence was graded and recommendations were given based on the strength of the available data in the medical literature.

Clinical approach to a child with abdominal pain who might have appendicitis

Appendicitis can usually be diagnosed on completion of a history and physical examination (abdominal pain, vomiting, right lower quadrant tenderness and guarding), although laboratory evaluation with a urinalysis and white blood cell count can be of assistance. In the few cases where doubt remains, plain films of the chest and abdomen can be helpful. Whether and when further imaging is indicated remains controversial. We reviewed reports of studies published since 2003 in which the sensitivity and specificity of CT and sonography for diagnosing appendicitis were determined. Sonography had an average sensitivity of 87.1% and an average specificity of 89.2% in the nine studies reported during that period. The average sensitivity of CT was 90.8% in 11 studies during that period, and there was an average specificity of 94.2% in 10 studies. We also looked at data from 299 patients who underwent appendectomies at our hospital. Of the appendices removed, only 10.7% did not have appendicitis. In many cases, CT or US imaging data were available in the form of reports or images or both from outside institutions. CT and US images were also available from our institution when the diagnosis was in question. This is how patients present in the real world-with studies that might not be the best, might not have been indicated, and might not have images available for another interpretation. Among patients operated on with neither CT nor US images, 10.9% did not have appendicitis. Among those in whom US imaging had been performed, 11.1% were negative for appendicitis, and among those in whom CT had been performed, 9.7% were negative. Although these studies were necessary because they were performed in patients whose diagnosis was the most difficult, it is in every patient's best interest to have a thorough examination by a surgeon prior to having a CT scan.

Update on appendicitis: diagnosis and presurgical management

PURPOSE OF REVIEW

Practitioners who see pediatric patients with acute complaints are commonly faced with making the diagnosis of appendicitis. While sometimes the history and physical examination are sufficient, frequently some diagnostic confirmation will be necessary. While diagnostic imaging is frequently useful, it may not be easily obtained. Blood tests are more readily available, with less cost and risk, but unclear diagnostic accuracy. Other questions for the initial examiner are when to consult the surgeon and if analgesia administration will obscure the diagnosis.

RECENT FINDINGS

Abdominal computed tomography scans and ultrasound scans have been shown to be accurate in the diagnosis of acute appendicitis. The literature has begun to focus on which patients should undergo imaging studies. Several clinical decision rules that may be helpful in identifying low-risk patients have been derived. Analgesia given before establishing a diagnosis does not appear to change outcomes.

SUMMARY

A careful history and physical examination will identify a minority of pediatric appendicitis cases. When diagnostic testing is needed, computed tomography scanning has the best test performance, but also carries the risk of radiation. Elimination of a portion of low-risk patients may reduce unnecessary imaging.