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TOXIC MEGACOLON IN CHILDREN WITH INFLAMMATORY BOWEL DISEASE: CLINICAL AND RADIOGRAPHIC CHARACTERISTICS
EI Benchimol, D Turner, EH Mann, KE Thomas, T Gomes, RA McLernon, AM Griffiths
Division of Gastroenterology, Hepatology & Nutrition, The Hospital for Sick Children, University of Toronto, Toronto, Ontario
BACKGROUND: Toxic megacolon (TMC) denotes a rare clinical syndrome accompanied by colonic dilatation, and is a serious complication of inflammatory bowel disease (IBD). Our goal was to assess the clinical and radiologic characteristics of TMC in children with IBD.
METHODS: A systematic chart search identified 10 TMC cases in IBD patients (8 UC, 2 Crohn’s) over a 27-year period. This case-control study matched the 10 cases with 20 severe ulcerative colitis (UC) controls by age. Clinical characteristics, outcomes and radiology were compared with conditional logistic regression. Abdominal x-rays were interpreted by two independent radiologists and findings were compared with UC controls.
RESULTS: Altered level of consciousness and hypotension were rare in children with TMC. Fever (p=0.005), tachycardia (p=0.0001), dehydration (p=0.01) and electrolyte abnormalities (p=0.0002) were more common in children with TMC than controls. Air-fluid levels (p=0.005), intestinal thickening (p=0.006) and abnormal colonic haustra (p=0.012) were more commonly seen on x-rays of TMC cases than controls. Differences were noted in mean luminal diameters of the transverse colon (65.8 ± 17.5 mm vs 33.3 ± 19.4 mm, p=0.0001) and small bowel (28.7 ± 6.2 mm vs 18.6 ± 7.7 mm, p=0.0005). Transverse colon luminal diameter =>56 mm was strongly suggestive of TMC (sensitivity 90%, specificity 90%, area under the receiver operating characteristic curve (AUROC) 0.91). Small bowel luminal diameter =>24.5 mm was moderately suggestive of TMC (sensitivity 70%, specificity 75%, AUROC 0.87). No child with TMC died and 70% required colectomy during admission, compared with 30% colectomy rate in UC controls. At one year follow-up, two of three patients with TMC required second-line therapy, but no further colectomies were performed.
CONCLUSIONS: Severe colitis, clinical signs and an x-ray showing colonic dilatation => 56 mm strongly suggests TMC in children. Some signs such as mental alteration and hypotension may be less common in children than in adults. TMC in children with IBD is associated with poor outcome, with a high rate of second-line therapy and colectomy.