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, including:
- Parkinson's disease.
- Liver
failure.
- Alcoholism.
- Drug and alcohol
withdrawal.
- Mercury or arsenic poisoning.
- Medications
such as lithium, drugs taken for arrhythmias and high blood pressure, tricyclic
antidepressants, and theophylline.
