Sudden decline in eGFR in the elderly

92 yr old drop in eGFR by 9 in less than a month currently sits at 35. Pacemaker procedure 4 weeks ago all vitals now are stable all other bloodwork is normal Increased memory loss, feeling unwell other symptoms of dizziness, stomach bloating, sweating off, heavier breathing on and off consitantly feeling unwell. CT scan in 3 weeks ultrasound came back clear. Trying to figure out if this is CKD, normal aging process, psychological issues or all of the above. Also if a CT is dangerous for her with or without contrast. Has not been referred to a neuphologist yet.