A PATIENT WAS ON LITHIUM THERAPY FOR BIPOLAR DISORDER FOR 6MONTHS SHE KEPT THE FAST FOR FEW DAYS .SHE PRESENTED WITH S3 , COARSE TREMORS , CONFUSION AND WEAKNESS OF LIMBS. WHICH OF THE FOLLOWING SHOULD BE DONE NEXT TO ASSESS HER CONDITION ?
REF : KD TRIPATHI 8TH ED
S.ELECTROLYTES
ECG
MRI
S.LITHIUM LEVELS
All India exam