Both hands shivering from past few days.

My Mom is 57 years old and from past few days her both hands are shivering and unable to hold or write anything.. particularly left hand shaking lot than right one.. shivering lasting whole day and during after bath left hand shivering more and fingers are getting folding. Please let me know what may be the cause for the issue.. recently taken blood test and her hemoglobin level (HGB) is just 6.3 (12-16 normal) and WBC count is 11.3 (4-10 normal). Is HGB causes hand shivering or what could be the reason for the issue.. is hand shaking symptoms of any diseases ( particularly related to brain).. pls assist me what kind of test and tretment needs to be done for this issue. Is it hand shivering is a severe problem ?