Final analysis was performed on the remaining 197 assessable cases. There was considerable variability in the annual number of episodes of intussusception diagnosed. The average incidence rate over the 8-year study Libraries period was 1.91 per 10,000 children aged <24 months (95% CI: 1.65, 2.20) and 2.65 per 10,000 (95% CI: 2.23, 3.13) for infants aged <12 months PD98059 (Table 2). The estimated incidence rate ratio over the study period for children aged <24 months was 0.97 (95% CI 0.92, 1.03) and 0.96 (95% CI 0.90, 1.03) for infants aged <12 months. This suggests a small decline in incidence over this 8-year study, however, the confidence

intervals were wide reflecting the small number of cases in this study. Over 75% of episodes occurred in infants aged <12 months, peaking between 5 and 9 months of age (Fig. 1). Median age at presentation for infants <12 months was 7 months and 10 months for all children aged <24 months. No infant <2 months of age had a diagnosis of primary intussusception made during this study, or in the previous published study, which in combination, span 14 years experience at the Royal Children's Hospital. There was a male to female ratio of 2:1 (Table 1). Over 25% of patients reported either a respiratory and/or gastrointestinal

illness GSK1120212 in the 2 weeks prior to developing intussusception (Table 1). Evidence of any previous significant illness or hospitalisation was identified in 24 patients (12%) including a co-morbidity at the time of diagnosis of intussusception in 13 patients. However, these conditions were not assessed to have attributed to the development of the intussusception in these patients. There were no deaths during the intussusception related admissions over the study period. During the chart

review it was noted that one patient died 3 years after an admission for intussusception due to complications of an unrelated malignancy. No family history of intussusception was identified and limited 4-Aminobutyrate aminotransferase data was available in the medical records to assess a potential role of diet in the pathogenesis of the intussusception episode. No seasonal variation in hospitalisation due to intussusception was identified in this study. The most frequently observed symptom was vomiting (89%) which was described as bile stained in 69 patents (35%). The combination of crying, irritability and abdominal pain were frequently described by parents or observed by medical staff (n = 155 [79%]). The classically described triad of vomiting, abdominal pain and bloody stool or rectal bleeding was observed in only 38 patients (19%). Ultrasound was used to confirm the diagnosis of intussusception in 148 (75%) patients, whilst an abnormal abdominal radiograph was requested in 35 (18%) patients. Most intussusceptions involved the ileo-colic region (115/139 assessable cases [83%]).