Hi My Wife Developed Chronic Kidney Disease Stage 5 Like

Hi my wife developed Chronic Kidney Disease stage 5 like out of the blue ! Her bloodwork in Jan 2015 was creatine 0.93 and GFR was 66. Now as of Friday 11/13/15 it was 3.57 and GFR was 13. What could have happened to make this go haywire so soon. Her sodium was low as well 129 on Friday. She is 103 pounds and 5"2". Also her Hemoglobin is 8.0 and Hermatocrit 24.8 ? Please help ! Urgent !