Hello,my mother is forty-three year old,from April 7 to up nao,my mother‘s left crus is red and swollen, a little hot, also a little pain ,but walking is feeling well。 She has seen orthopedics, department of traumatology, urology department ,has no effect。the doctor‘s of urology department told my mother that has chronic nephritis ,but it has nothing with left crus。I want to know what it is illness