Colonic wall thickening is related to age and not dose of high strength pancreatin microspheres in children with cystic fibrosis

Colonic fibrosis causing stricture is a recently described complication in cystic fibrosis (CF). Studies have suggested that ultrasound evidence of bowel thickening predicts this complication and that it is prevalent among children receiving large doses of high-strength pancreatin preparations. We performed ultrasound studies on our patients to look for evidence of bowel wall thickening or early stricture. Detailed colonic ultrasounds were carried out in 33 children with CF including 25 who had been receiving high-strength pancreatin (Creon 25,000) continuously for 3 years at the time of study. Median lipase intake was 19 330 U/kg/day (range 0-59 880 U/kg/day) and median protease intake was 387 U/kg/day (range 0-1170 U/kg/day). The combined thickness of mucosa, sub-mucosa and muscle layers was measured in ascending, transverse and descending colon using a 7.5 MHz transducer. Measurements were also made in nine healthy controls. There was no relationship between enzyme dosage and colon thickness but simple regression identified a significant relationship (P < 0.001) between age and maximum colon thickness in all three areas. The colon of CF children was up to 50% thicker than in controls. Thickening of the order described elsewhere did not occur among any of the children studied. The results suggest that the most important factor determining the thickness of the CF colon is age.