Magnetic Resonance Defecography: An Underused Modality for Evaluation and Management of Refractory Constipation in a Child

Case DesCriptionA 15-year-old boy presented with painful defecation associated with blood and mucus-mixed semisolid stools, occurring six to eight times per day for the past 2 years.Most episodes involved passage of only 5-10 mL fresh blood and mucus, with no history of melena.This was associated with excessive straining and sensation of incomplete evacuation.There was no history of fever, weight loss, oral ulcers, or joint pain.There was no significant past or family history.He was evaluated at a local hospital at 14 years of age, where colonoscopy revealed rectal ulcers (histopathology showed nonspecific colitis), and he was started on topical 5-aminosalicylic acid (5-ASA) for suspected ulcerative proctitis.As there was no improvement, medications were discontinued after 5 months.He was also given a trial introDuCtion Refractory constipation (RC) accounts for approximately 20-30% of constipation cases in children coming to pediatric gastroenterology clinic. 1 It is defined as persistence of constipation despite adequate treatment compliance for at least 3 months. 2In some instances, RC may manifest through symptoms that represent complications, necessitating a heightened level of clinical suspicion in such presentations.The evaluation of patients with RC requires a detailed clinical history and basic evaluation with thyroid profile, tissue transglutaminase (TTG) immunoglobulin A (IgA), and serum calcium levels to rule out potential underlying causes.Further evaluation is warranted in refractory cases, with advanced investigations like colonic transit time (CTT) studies, followed by either colonic manometry (CM) in case of slow transit, or high-resolution anorectal manometry (HRAM) with or without magnetic resonance defecography (MRD) or fluoroscopic defecography (FD) in case of outlet obstruction on CTT.Defecography is a dynamic radiologic test performed during the voluntary evacuation of the rectum to assess the pelvic floor and puborectalis muscle at rest and during defecation, and can diagnose various pelvic floor disorders such as paradoxical puborectalis contraction syndrome, rectocele, intussusception, and perineal descent. 3While FD has been widely utilized in various studies, there are limited data on the use of MRD in children with RC.This case report underscores the critical importance of thorough clinical history, physical examination, and the role of MRD in the evaluation and management of RC in children.