Accuracy of fecal calprotectin, bowel ultrasonography and inflammatory indexes in the diagnosis of paediatric inflammatory bowel disease

Introduction. Inflammatory bowel disease (IBD) in pediatric age may present with non specific gastrointestinal symptoms overlapping with functional bowel disorders making the diagnosis a challenge. A delay in diagnosis and a late introduction of immunosuppressive therapy have been associated with an increased risk of IBD progression and complications and with the need of surgery. The aim of our study was to assess the accuracy of non-invasive parameters including fecal calprotectin (FC), bowel ultrasound wall thickening (BWT) and blood inflammatory indexes (BII) alone or in combination as a diagnostic tool for paediatric IBD. A diagnostic algorithm was also proposed. Methods. Subjects aged 2-18 years referred to our paediatric gastroenterology clinic from 2007 to 2013 for recurrent abdominal pain and/or altered bowel habits were retrospectively considered. Subjects who underwent laboratory tests (FC, BII: white blood cell count, C-reactive protein, erythrocyte sedimentation rate) and bowel ultrasound as initial assessment were eligible. Exclusion criteria were: signs or symptoms highly suggestive for IBD (perianal disease or haematochezia), known organic disease, previously performed endoscopy. Eligible patients were followed-up for one year.Results. Seventy-seven patients (mean age 11.3, 44 males) were retrospectively included. One-year diagnoses were: 23 (29.9%) IBD and 54 (70.1%) non-IBD diseases. FC alone presented highest sensitivity but poor specificity (95.6% and 72.2%, respectively). The probability of having IBD in the presence and in the absence of all three parameters (FC + BII + BWT) were 98.3% and 0.09%, respectively. The combination of FC + BWT presented the highest accuracy in identification of children with IBD (positive predictive values: 100%, negative predictive values: 88.5%). Diagnostic accuracy of considered parameters is described in table 1. Conclusion. In initial work-up for paediatric IBD, combination of fecal calprotectin and bowel ultrasound wall thickening is useful in the identification of children needing further invasive procedures as endoscopy in the short term.