Intussusception among children less than 2years of age: Findings from pre-vaccine introduction surveillance in Pakistan.

BACKGROUND: Rotavirus vaccination introduction in routine immunization is under consideration in Pakistan. Data on the baseline epidemiology of intussusception will inform surveillance strategies for intussusception after rotavirus vaccine introduction in Pakistan. We describe the epidemiology of intussusception-associated hospitalizations among children <2years of age in Karachi, Pakistan. METHODS: We conducted a retrospective chart review for July 01, 2012 through June 30, 2015 at the National Institute of Child Health (NICH) and Aga Khan University Hospital (AKUH) Karachi. At AKUH, the International Classification of Disease, ninth revision, code 560.0 for intussusception was used to retrieve intussusception case records. At NICH, daily Operation Theater, Emergency Room, and surgical daycare log sheets and surgical ward census sheets were used to identify cases. Records of children who fulfilled eligibility criteria and the Brighton Collaboration level one case definition of intussusception were selected for data analysis. We used structured case report forms to extract data for the descriptive analysis. RESULTS: We identified 158 cases of confirmed intussusception; 30 cases (19%) were from AKUH. More than half (53%) of the cases occurred in children aged 6-12months, followed by 35% among those aged <6months. Two-thirds (106/158) of the cases were male. The most common presenting complaints were vomiting and bloody stool. At NICH, almost all (93%) were managed surgically, while at AKUH, ∼57% of the cases were managed with enemas. Three deaths occurred, all from NICH. Cases occurred without any seasonality. At NICH, 4% (128/3618) of surgical admissions among children aged <2years were attributed to intussusception, while that for AKUH was 2% (30/1702). CONCLUSION: In this chart review, intussusception predominantly affected children 0-6months of age and occurred more commonly in males. This information on the baseline epidemiology of intussusception will inform post-vaccine introduction adverse event monitoring related to intussusception in Pakistan.