HI
Thanks for posting your query to HCM .
There are quite a few causes for such Unconscious spells . I will tell about few common cause .
1.
Seizure Disorder : A condition which causes convulsions ( fits )
2. Stroke : Inadequate Blood Supply or Bleeding inside the Brain .
Cause for Seizure is
Electrolyte Imbalance ( Low / HIgh Blood Sodium, Calcium Magnesium levels , Low / HIgh Blood Sugars ), Infection spreading to Brain , Some Mass in the Brain , Epilepsy , Liver Failure , Kidney Failure .
Cause for Stroke are
Uncontrolled Hypertension ,
Uncontrolled Diabetes , Elevated Cholesterol , Smoking , Alcoholism , Disorders in Blood Coagulation .
I advise you to get MRI Brain , Serum Sodium , Calcium ,
Lipid Profile , 2D-ECHO and revert back with reports .