"Numbness and tingling in the arms and hands, muscle weakness, pain in the fingers and toes, and loss of balance are often symptoms of conditions or diseases such as peripheral neuropathy, Vitamin B12 deficiency, or a medical problem that is secondary to other conditions such as diabetes and vitamin deficiencies. These could also be side effects associated with certain pharmaceutical drugs."
Diabetic neuropathy is a common companion of diabetes. Peripheral neuropathy can be caused by vitamin B12 deficiency. If you are vegetarian or vegan, if you are an alcoholic or if you don't produce enough stomach acid, you could have a vitamin B12 deficiency.
Hypothyroidism, from an underactive thyroid gland, causes your body to slow down and excess fluid is retained. This can apply extra pressure to nerves, causing numbness and tingling, pain and muscle weakness. Lupus, an autoimmune disorder, can cause nerve damage resulting in these symptoms.
Some denture creams containing high zinc levels, some chemotherapy drugs and some statin drugs may cause neuropathy.
http://www.usrecallnews.com/2009/09/numbness-tingling-arms-hands.html