20 y/o female with compression fx at t11 & degenerative disc disease between c5-c6 & l4-l5. mri & dexa just ordered. ideas on what could cause this?

Compression fracture: 20 y/o is too young to osteoporosis but some conditions may lead to early one such as cystic fibrosis. Trauma is by far the leading cause for such things then if a pathological fracture is suspected, diseases that involve bone need to be ruled out (infections, tumors...). Further history can probably narrow down the differential.