I agree - it sounds like Remicade is not fully controlling the disease if her Fecal Calprotectin is still high. She may need a higher dose or more frequent infusions or both. She may also need to add Methotrexate. It's different for every kiddo and it takes time to find the right combination of medications.
My daughter started at 5 mg/kg every 5 weeks or so and then eventually upped it to 7.5 mg/kg and then 10 mg/kg every 4-5 weeks. That really worked for her. It took months to find the right dose and frequency and she was also on MTX.
I also agree with getting a second opinion. Amitriptyline/Elavil will control pain but not inflammation. You need to control the inflammation first. IF once there is no inflammation and there is still excessive pain, then I'd try the Elavil. I wouldn't try two things at once because you need to know what's working and honestly, getting the inflammation under control should really help her with the pain.
A second opinion and a second set of eyes never hurts and it seems like your current GI is not considering the fact that there is still inflammation that could be driving the pain. Good doctors welcome a second opinion, particularly in difficult cases. We've done several second opinions for my daughter when we thought things were not right.
My daughter also has severe arthritis and has gone down the amplified pain route. She has done an intensive pediatric pain rehab program as well as outpatient PT, OT, acupuncture, using a TENS unit, cognitive behavioral therapy with a psychologist, plus there are meds like Elavil, Gabapentin, Lyrica etc. BUT we only did the pain rehab program once her inflammation was controlled. It's definitely something to think about if she continues to have pain that is disproportionate to the amount of inflammation or if there is no inflammation.
But first I'd get a second opinion and try to get her Fecal Calprotectin down and the inflammation controlled, particularly since it sounds like she hasn't been on Remicade for very long. And do remember that healing takes time (think months, not weeks). Plus there are other med options if that does not work - other biologics like Humira or Stelara.
I'll tag some other parents who may also be able to help:
@crohnsinct
@Pilgrim
@pdx