Imaging of acute appendicitis in children

Maximum intensity projection aids in diagnosing acute appendicitis and mobile caecum: A case report and literature review

Appendicitis is a common childhood condition requiring surgical intervention and delayed diagnosis can have serious consequences. This report describes the case of a child who presented with an acute abdomen and intestinal obstruction. Multidetector (MD) CT demonstrated a left-sided caecum and an inflamed appendix with a faecolith. Maximum intensity projection (MIP) post-processing was key in identifying the appendicular artery and determine the diagnosis. At surgery, however, a mobile caecum and the appendix were positioned on the right side.

The Use of Ultrasonography to Assess Patients with Right Lower Quadrant Pain in the Emergency Department

Acute appendicitis is always a clinical challenge to emergency physicians. Clinical examination or blood tests are notoriously unreliable in making the diagnosis, especially in the early phase of the disease. Computed tomogram can facilitate the diagnosis, however it is usually not easily accessible to emergency physicians. Bedside ultrasonography is now frequently used by emergency physicians in various situations for the assessment of patients. This study aimed at exploring the potential use of bedside ultrasonography in the diagnosis of acute appendicitis in patients presenting with right lower quadrant abdominal pain.

Computed Tomography Utilization for the Diagnosis of Acute Appendicitis in Children Decreases With a Diagnostic Algorithm

OBJECTIVE

The primary objective of this project was to decrease computed tomography (CT) utilization for the diagnosis of appendicitis in an academic children's hospital emergency department (ED) through a multidisciplinary quality improvement initiative.

BACKGROUND

Appendicitis is the most common abdominal diagnosis leading to the hospitalization of children in the United States. However, the diagnosis of appendicitis in children can be difficult and many centers rely heavily upon CT scans. Recent recommendations emphasize decreasing CT use among pediatric patients because of an increased lifetime risk of radiation-induced malignancies.

METHODS

A retrospective review was conducted of patients diagnosed with appendicitis in the ED at Children's Mercy Hospital from January 1, 2011 to February 28, 2014 to establish a baseline cohort. From August 1, 2014 to July 31, 2015, a newly designed diagnostic algorithm was used in the ED and patients were prospectively followed. Any patient discharged from the ED received a follow-up phone call. Patients treated for appendicitis before and after pathway implementation were compared. In addition, any patient evaluated for appendicitis after implementation of the algorithm was analyzed for adherence to the clinical pathway. Differences between the 2 groups were analyzed using ANOVA, Wilcoxon Rank Sum, χ, and Fisher Exact tests.

RESULTS

Of 840 patients seen after implementation of the diagnostic algorithm, 267 were diagnosed with appendicitis. After implementation of the algorithm, CT utilization decreased from 75.4% to 24.2% (P < 0.0001) in patients with appendicitis. CT utilization was 27.3% after implementation, regardless of the ultimate diagnosis or algorithm adherence. The diagnostic pathway had a sensitivity of 98.6% and specificity of 94.4%.

CONCLUSIONS

Implementation of a diagnostic algorithm for appendicitis in children significantly decreases CT utilization, whereas maintaining a high sensitivity and specificity.

Ultrasound for Appendicitis: Performance and Integration with Clinical Parameters

Objective. To evaluate the performance of ultrasound in pediatric appendicitis and the integration of US with the pediatric appendicitis score (PAS) and C-reactive protein (CRP). Method. An institution-based, retrospective study of children who underwent abdominal US for suspected appendicitis between 2012 and 2015 at a tertiary pediatric surgery center. US results were dichotomized, with a nonvisualized appendix considered as a negative examination. Results. In total, 438 children were included (mean 8.5 years, 54% boys), with an appendicitis rate of 29%. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for US were 82%, 97%, 92%, and 93%, respectively, without significant age or gender differences. Pediatric radiologists had significantly higher sensitivity compared to general radiologists, 88% and 71%, respectively (p < 0.01), but no differences were seen for specificity, PPV, and NPV. The sensitivity, NPV, and negative likelihood ratio for the combination of negative US, PAS < 5, and CRP < 5 mg/L were 98%, 98%, and 0.05 (95% CI 0.03–0.15). Conclusion. US may be a useful tool for evaluating children with suspected appendicitis, regardless of age or gender, and should be the first choice of imaging modalities. Combining US with PAS and CRP may reduce several unnecessary admissions for in-hospital observation.

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.

Point-of-care ultrasound in a patient with perforated appendicitis

We present the case of an 8-year-old girl with two emergency department visits for constipation and abdominal pain. Her medical history and physical examination noted by the emergency physician did not reveal a clear etiology of her symptoms until the second visit, when a point-of-care ultrasound was performed. The sonographic findings were consistent with a fecalith surrounded by fluid concerning for appendiceal rupture. A computerized tomographic scan of the abdomen confirmed these findings in addition to two large abscesses in the lower pelvis, which subsequently required percutaneous drainage. This case illustrates the utility of point-of-care ultrasound in the evaluation of the pediatric patient with abdominal pain when appendicitis is a concern, as well as the ability of the emergency physician to use this technology to guide treatment and care of pediatric patients.

Extra-appendiceal findings in pediatric abdominal CT for suspected appendicitis

BACKGROUND

Much has been written regarding the incidence, types, importance and management of abdominal CT incidental findings in adults, but there is a paucity of literature on incidental findings in children.

OBJECTIVE

We sought to determine the prevalence and characteristics of extra-appendiceal and incidental findings in pediatric abdominal CT performed for suspected appendicitis.

MATERIALS AND METHODS

A retrospective review was performed of abdominal CT for suspected appendicitis in a pediatric emergency department from July 2010 to June 2012. Extra-appendiceal findings were recorded. Any subsequent imaging was noted. Extra-appendiceal findings were divided into incidental findings of doubtful clinical significance, alternative diagnostic findings potentially providing a diagnosis other than appendicitis explaining the symptoms, and incidental findings that were abnormalities requiring clinical correlation and sometimes requiring further evaluation but not likely related to the patient symptoms.

RESULTS

One hundred sixty-five children had abdominal CT for suspected appendicitis. Seventy-seven extra-appendiceal findings were found in 57 (34.5%) patients. Most findings (64 of 77) were discovered in children who did not have appendicitis. Forty-one of these findings (53%) could potentially help explain the patient's symptoms, while 30 of the findings (39%) were abnormalities that were unlikely to be related to the symptoms but required clinical correlation and sometimes further work-up. Six of the findings (8%) had doubtful or no clinical significance.

CONCLUSION

Extra-appendiceal findings are common in children who undergo abdominal CT in the setting of suspected appendicitis. A significant percentage of these patients have findings that help explain their symptoms. Knowledge of the types and prevalence of these findings may help radiologists in the planning and interpretation of CT examinations in this patient population.

A simple algorithm reduces computed tomography use in the diagnosis of appendicitis in children

BACKGROUND

A diagnostic algorithm for appendicitis in children was created to reduce computed tomography (CT) use owing to the risk of cancer from radiation exposure and cost of CT. This study evaluates the impact of the algorithm on CT use and diagnostic accuracy of appendicitis.

METHODS

Patients ≤18 years who underwent appendectomy for suspected appendicitis after presenting to the emergency department for 2 years before and 3 years after algorithm implementation were identified. Clinical characteristics and outcomes, including use of CT and negative appendectomy rate, were compared between the pre- and post-implementation periods. Multivariable analysis was used to determine the impact of CT on negative appendectomy.

RESULTS

We identified 331 patients-41% in the pre- and 59% in the post-implementation period. CT utilization decreased from 39% to 18% (P < .001) after implementation. The negative appendectomy rate increased from 9% to 11% (P = .59). Use of CT did not impact the risk of negative appendectomy (P = .64).

CONCLUSION

Utilization of CT was significantly reduced after implementation of a diagnostic algorithm for appendicitis without impacting diagnostic accuracy. Given the concern for increased risk of cancer after CT, these results support use of an algorithm in children with suspected appendicitis.

Revised ultrasound criteria for appendicitis in children improve diagnostic accuracy

BACKGROUND

Use of CT in the evaluation of suspected appendicitis in children is common. Expanding the use of US would eliminate the radiation exposure associated with CT.

OBJECTIVE

We describe new criteria that improve US's diagnostic accuracy for appendicitis, making it more comparable to CT in terms of sensitivity and specificity.

MATERIALS AND METHODS

We conducted a retrospective review of 304 consecutive patients undergoing US for the diagnosis of appendicitis in our institution during 2006. The sensitivity, specificity and accuracy of the maximal outer diameter (MOD) at various measurements was calculated and compared to pathology results. Additional variables (appendiceal wall thickness, fecalith, hyperemia, fat stranding, free fluid, age and weight) were also evaluated.

RESULTS

The highest sensitivity (98.7%) and specificity (95.4%) were identified when MOD was ≥7 mm or wall thickness was >1.7 mm. These values resulted in correctly classifying 96.6% of cases, with 1 (0.5%) false-negative and 6 (2.9%) false-positive studies. Incorporating secondary signs of appendicitis, age or weight did not alter accuracy.

CONCLUSION

These findings identify new US criteria that compare favorably to CT. In children with suspected appendicitis, using US as the initial imaging study will ultimately lead to improved accuracy, lower cost and the elimination of ionizing radiation exposure.

Sonographic findings following appendectomy for uncomplicated appendicitis in children

BACKGROUND

Little is known about 'normal' local sonographic changes occurring in the postoperative period after an uneventful appendectomy.

OBJECTIVE

To analyse the local changes on US examination occurring after uneventful open (OA) or laparoscopic (LA) appendectomy in children with normal histology and with nonperforated acute appendicitis.

MATERIALS AND METHODS

US was prospectively performed in 82 children (54 boys and 28 girls) aged 1-16 years (mean 11.6+/-3.2 years), 3 days following LA (n=51, 62%) or OA (n=31, 38%) for nonperforated appendicitis. Multivariate analysis was performed using stepwise logistic regression, with the following starting variables: surgical technique, gender, pathological finding, appendix location, and histology.

RESULTS

Of the 82 patients, 35 (42.7%) had postoperative pathological US findings such as peritoneal fluid, oedematous mesenteric fat and thickening of the bowel wall. While the overall incidence of pathological US findings between OA and LA groups was not significantly different, multivariate logistic regression analysis showed that OA is associated with a reduction by a factor of 0.35 in the odds ratio of postoperative pathological US findings (P=0.007).

CONCLUSION

Pathological US findings are common in children after appendectomy, particularly after LA. Awareness of these pathological findings might prevent unnecessary postoperative treatment.

Optimizing the role of imaging in appendicitis

Acute appendicitis is the most common acute abdominal condition that requires surgical intervention in childhood. From the diagnostic performance perspective, computed tomography (CT) has a significantly higher sensitivity than does ultrasound (US) for diagnosing appendicitis in children; from the safety perspective, however, one should consider the radiation associated with CT, especially in children. There is strong evidence supporting improved patient outcomes in children with suspected acute appendicitis who undergo CT scanning. Nevertheless, we should keep in mind that for a single abdominal CT study in a 5-year-old child, the lifetime risk of radiation-induced cancer would be 26.1 per 100,000 in female and 20.4 per 100,000 in male patients, based on probabilistic models designed with data from atomic bomb survivors. An integrated clinical-imaging approach, applying clinical scores that are able to predict which children with acute abdominal pain do or do not have a high probability of presenting with appendicitis may improve the effectiveness of the imaging diagnosis of appendicitis at the hospital level. Such an approach could avoid exposure of children who at low risk for appendicitis to unnecessary diagnostic tests and eventually, to radiation.

[Association of streptococcal pharyngitis with complicated appendicitis]

Streptococcal pharyngitis can be accompanied by right lower abdominal quadrant pain, which often is linked to mesenteric adenitis. We report on a case of such misleading association in a child.

CASE REPORT

A 6-year-old child presented pain in the right lower abdominal quadrant and fever with 39 degrees C temperature for 24 h; clinical examination showed pharyngeal erythema and local abdominal tenderness. Strep-test was positive. Abdominal ultrasound visualized signs of appendicitis. The child was operated on for complicated appendicitis.

COMMENTS

The association of pharyngitis and appendicitis is particularly misleading because mesenteric adenitis is the most common cause of right lower quadrant tenderness in children with pharyngitis.

Atypical clinical features of pediatric appendicitis

BACKGROUND

The diagnosis of appendicitis remains challenging in children. Delays in diagnosis, or misdiagnosis, have important medical and legal implications. The typical, or classic, presentation of pediatric appendicitis has been modeled after adult disease; however, many children present atypically with subtle findings or unusual signs.

OBJECTIVES

To determine the frequency of atypical clinical features among pediatric patients with appendicitis and to investigate which atypical features are the strongest negative predictors for appendicitis among patients being evaluated for appendicitis.

METHODS

Children and adolescents with suspected appendicitis were enrolled over 20 consecutive months. Pediatric emergency physicians completed standardized data collection forms on eligible patients. Final diagnosis was determined by pathology or follow-up telephone call. Typical and atypical findings were defined strictly a priori.

RESULTS

Seven hundred fifty-five patients were enrolled. The median age was 11.9 years (interquartile range [IQR]: 8.5, 14.9 yr); 36% of patients were diagnosed with appendicitis. Among patients with appendicitis, the most common atypical features included absence of pyrexia (83%), absence of Rovsing's sign (68%), normal or increased bowel sounds (64%), absence of rebound pain (52%), lack of migration of pain (50%), lack of guarding (47%), abrupt onset of pain (45%), lack of anorexia (40%), absence of maximal pain in the right lower quadrant (32%), and absence of percussive tenderness (31%). Forty-four percent of patients with proven appendicitis had six or more atypical characteristics. The median number of atypical features for patients with proven appendicitis was five (IQR: 4.0, 7.0). The greatest negative predictors, on the basis of likelihood ratios, were as follows: white blood cell count (WBC) of <10,000 per cubic millimeter (likelihood ratios [LR], 0.18), absolute neutrophil count (ANC) of <7,500 per cubic millimeter (LR, 0.35), lack of percussive tenderness (LR, 0.50), lack of guarding (LR, 0.63), and no nausea or emesis (LR, 0.65).

CONCLUSIONS

Appendicitis in pediatric patients is difficult to diagnose because children present with a wide variety of atypical clinical features. Forty-four percent of patients with appendicitis presented with six or more atypical features. Two atypical features are the strongest negative predictors of appendicitis in children: WBC of <10,000 per cubic millimeter and an ANC of <7,500 per cubic millimeter.

Appendiceal abscess drainage

Appendicitis is the most common abdominal inflammatory process in children, and the most frequent indication for abdominal drainage encountered in pediatric interventional radiology. Imaging in the diagnosis of appendicitis is evolving with CT becoming more common, although the incidence of perforation is not definitely improving. Tailored CT techniques for the diagnosis of acute appendicitis are designed to expedite care, but are not optimal in the diagnosis or characterization of abscesses. In the appropriate clinical setting the CT study needs to be altered for appropriate therapeutic planning. Drainage of appendiceal abscesses utilizes multiple techniques, some of which are more useful in children than adults. Image-guided drainage can facilitate a more limited surgery and can avoid repeat surgery from postoperative abscesses. Radiation doses must be minimized due to the increased risk in children. This article will discuss imaging in children with suspected appendiceal abscesses and drainage techniques.