although I've had a fistula in the past, I really can't comment much on your daughters situation because I'm a male and my fistula was in a different location. However, frequent urination could also be signs of a bladder infection...fistulas usually cause leakage (usually from pus) and often require surgery to fix.
Diagnosed with Ulcerative Colitis January 2007
Remicade, Primal Defense Ultra, Multi-vitamins (also iron, B12, Magnesium and Zinc), Flaxseed/Natures Bounty Fish Oil
Swanson Ultra Caprylic Acid (natural anti-fungal) 600mg x2 daily
Carrot & Garlic supplements (natural anti-fungal) x2 daily
Currently taking herbal meds in the search to regain full health.