Trembling, or tremor, of the hands is a rhythmic, uncontrollable shaking movement. Tremors may also affect other parts of the body. All healthy people experience hand tremors, although they are not usually visible to the naked eye, according to an article entitled "Tremor" by Sharon Smaga, M.D., in the October 15, 2003 issue of "American Family Physician." When tremors become noticeable, a variety of causes may be involved. A physician should be consulted to determine the reason for hand tremors.
Essential Tremor
Essential tremor is the most common cause of trembling hands. The cause of essential tremor is unknown, although dysfunction of the cerebellum -- the part of the brain that controls movement -- is suspected. Essential tremor may be an inherited disorder. Onset is usually in middle age. Besides the hands, essential tremor may affect the head, arms, eyelids and voice "box." The voice may have a quivering quality. The tremors may be action related. Writing and using silverware may become difficult. Treatment with medications such as beta-blockers and primidone, an anti-seizure drug, may help if essential tremor interferes with activities of daily living, according to MedlinePlus.
Parkinsonian Tremor
Parkinsonian tremor occurs when at rest, rather than being related to action. It is caused by damage to the cerebellum. Parkinsonian tremor may be a sign of impending Parkinson's disease; it may occur without other symptoms or be seen in relation to other disorders. This tremor is characterized by a "pill-rolling" movement of the hands, according to the National Institute of Neurological Disorders and Stroke. The trunk, chin, lips and legs may also be affected. Onset is usually after age 60, and it commonly begins on one side of the body.
Drug-Induced Tremor
Certain drugs magnify the normally present, yet invisible, physiological tremor all humans have. Bronchodilators, pseudoephedrine, tricyclic antidepressants and Prozac are common causes of drug-induced tremor. Lithium may cause tremors, and toxicity can permanently damage the cerebellum, resulting in tremors that do not resolve, according to Dr. Smaga. Haloperidol, metoclopramide and Reglan may cause parkinsonian tremors. Other drugs that cause tremors include amphetamines, Ritalin, thyroid hormones and caffeine.
Tremors may also result from withdrawal from certain drugs, such as alcohol and benzodiazepines.
