A tremor is an involuntary, repetitive, rhythmic shaking or
twitching movement. Tremors usually affect the hands and head, but may
occasionally occur in the feet or torso.
Essential tremor, which
sometimes runs in families, is one of the most common types of tremors. It
causes shaking that is most noticeable when the person is doing something like
lifting a cup or pointing at an object. The tremor may also affect the person's
voice. The shaking caused by essential tremor only occurs when a person moves.
Medication can help reduce the shaking.
Tremors can also be caused
by caffeine and conditions or medications that affect the nervous system,
Drug and alcohol
Mercury or arsenic poisoning.
such as lithium, drugs taken for arrhythmias and high blood pressure, tricyclic
antidepressants, and theophylline.