Diagnostic Ultrasound for Possible Appendicitis

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AP Raghuthaman
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Full Name: A P Raghuthaman
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Diagnostic Ultrasound for Possible Appendicitis

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Possible Appendicitis? Study Supports Diagnostic Ultrasound
Linda Roach
December 30, 2013

Pediatric emergency departments can improve their diagnostic accuracy and expose fewer children to unnecessary radiation by adding selective ultrasonography to their diagnostic protocol for suspected appendicitis, according to a study published online December 30 in Pediatrics.Ashley Saucier, MD, from the Division of Emergency Services, Department of Pediatrics, University of Tennessee Health Science Center, and Children’s Foundation Research Institute at Le Bonheur Children’s Hospital, Memphis, Tennessee, and colleagues evaluated outcomes in 196 patients (aged 3 - 17 years) who presented at the University of Tennessee Health Sciences Center with abdominal pain. Under the study protocol, physicians assessed the patient's risk for appendicitis using a pediatric appendicitis score (PAS), which is a validated system commonly used in emergency departments. However, this 10-point scale of signs, symptoms, and findings from laboratory tests has been shown to have insufficient sensitivity and specificity to diagnose appendicitis by itself.

If the child had a PAS of 4 to 7 or was at intermediate risk, abdominal ultrasound imaging was performed at the treating physician's discretion. However, computed tomography (CT) scans were not part of the clinical pathway for such children. Children with high-risk PAS scores (≥8) were referred to a pediatric surgeon for management, and CT was performed only at the request of the surgeon.

This clinical pathway resulted in ultrasonography in 128 (65.3%) patients, and 48 (37.5%) of these exams were positive for appendicitis. CT scans were requested by the surgical consultants in 13 (6.6%) cases. Of the 65 patients diagnosed with appendicitis, none had a low-risk PAS score, 37 (56.9%; 95% confidence interval [CI], 44.4% - 69.2%) had an intermediate score and 28 (43.1%; 95% CI, 30.9% - 56.0%) had a high-risk score.Further analysis found that the pathway had diagnostic accuracy of 94% (95% CI, 91% - 97%), with a sensitivity of 92.3% (95% CI, 83.0% - 97.5%), specificity of 94.7% (95% CI, 89.3% - 97.8%), positive likelihood ratio of 17.3 (95% CI, 8.4 - 35.6), and negative likelihood ratio of 0.08 (95% CI, 0.04 - 0.19).

"Our results demonstrate that the diagnostic accuracy of our clinical pathway to risk-stratify patients with suspected appendicitis was superior to using the PAS alone, with significantly improved sensitivity and specificity," the researchers note.

This is important because it suggests that a PAS score combined with ultrasound could in most cases spare children with suspected appendicitis from undergoing CT, the researchers wrote. During the last decade, pediatricians have expressed alarm about the increasing use of CT for diagnosis in children because this exposes them to potential harm from the ionizing radiation.The authors have disclosed no relevant financial relationships.

Pediatrics. Published online December 30, 2013.

My comment- The accuracy of the PAS score will be dependent on the accuracy of the reading of Ultrasound.
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