Sensitivity and predictive value of ultrasound in pediatric cholecystitis

Background: Ultrasonography has a high sensitivity and positive predictive value (PPV) for diagnosing cholecystitis in adults. The objective of this study was to determine the sensitivity and PPV of ultrasonography in the diagnosis of pediatric cholecystitis. Methods: We performed a single-institution retrospective review of the records of all patients undergoing cholecystectomy with a preoperative ultrasound during 2005-2010. We calculated sensitivity, specificity, and PPV using pathologic findings as the standard for the diagnosis of cholecystitis. Results: In the 223 included patients, the median (interquartile range) age was 14 y (11-16 y); and 64% were female. Preoperative symptoms of abdominal pain were reported in 98% of patients. A diagnosis of cholecystitis was reported in 10% (23 of 223) of ultrasound readings. Pathologic diagnosis of cholecystitis was present in 80% (179 of 223) of cholecystectomy specimens, with 8% (15 of 179) having acute cholecystitis, 83% (148 of 179) chronic cholecystitis, and 9% (16 of 179) both. Sensitivity of ultrasound findings ranged from 6% for Murphy's sign to 66% for cholelithiasis. Positive predictive values ranged from 67% for Murphy's sign to 87% for gallbladder sludge. Presence of any one ultrasound sign had a sensitivity of 82% and PPV of 80%. Conclusions: Ultrasound findings in pediatric cholecystitis have lower sensitivities and PPVs than reported in adults. These differences may be explained by the higher prevalence of chronic cholecystitis in children, which suggests that children may have milder episodes of self-limited gallbladder inflammation compared with adults, which may lead to a delay in treatment.