Does History Of Polymyositis Cause Fibromyalgia In Later Stages?

When my doughter was 19 years old she was bed ridden with an undiagnosed case of polymyositis. By the time we got her into the hospital she was unable to walk. eat, brush her hair, or use bathroom facilities without a two or three person assist. She was in hospital for three months on very heavy doses of prednisone and methotrexate to combat the inflamation. My question is could this have lead to a later diagnosis of Fibromyalgia. She now is 40 years old and is unable to work, do any strenious activities and finds every day chore sometime unmanagable.