Hi. Thanks for your query. Noted the history and understood your concerns. Your daughter having fecal accidents incontinence with accidents can be due to the following reasons. First of all, Miralax it self can cause uncontrolled diarrhea and thus the fecal accidents, it is wonderful to know why is it continued orf started in the first place; stop this immediately. Second reason can be excessive mucus formation and thus causing passage or gas and stool easily even on slightest of straining. Any neurological cause that has weakened the anal sphincters. Since you have already consulted Pediatric Nephrologist, Gastroenterologist, and had had X-rays, ultrasound and all the things that you have mentioned. Hence I would advise you the following: First of all consult a Pediatric Surgeon. Get per-rectal digital examination to know whether the tone of muscles and sphincters around anus normal or not. Get an MRI of the lower spine as this may show a cause if neurological cause is found. Get the stool and blood tests done. IF there is any abnormality, get this treated. Pediatric colonoscopy may be of tremendous help.