The various causes of left hand shaking that is tremors is excessive alcohol consumption,stress, anxiety, or fatigue,parkinson's disease,low blood sugar,multiple sclerosis,over active thyroid that is hyperthyroidism.
You need urine tests,brain scans,blood tests -general & specific,EMG or nerve conduction studies,thyroid hormone tests. The treatment will be done according to the cause.
The exact diagnosis can only be made after physical examination & tests.So I advice you to make an appointment with your doctor.
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