Tremors are a very common physical finding. They mainly affect the hands, but can also be seen in the head, arms, legs, and the voice. Most people will notice their hands tremble a little from time to time and this is normal. The problem comes when tremors are persistent and/or interfere with normal activities.
A tremor is a shaking of a body part that cannot be controlled by the individual suffering from the tremor. Since nerves control the body’s movements, the cause of tremors can be due to changes either in the brain, where the nerve fibers begin, or in the nerves as they run to the body part they are controlling.
The brain and nervous system use a myriad of chemicals to transmit information from one nerve to another and from nerves to muscles. These chemicals can be complex neurotransmitters or simple elements such as calcium, sodium, and potassium. Abnormally increased or diminished amounts of these substances can lead to irregular nerve stimulation and subsequently to abnormal movements or tremors.
One well-known example is Parkinson’s disease. In this condition, cells in a particular area of the brain that produce the neurotransmitter dopamine gradually quit making enough of this chemical for normal motor function. This leads to progressive tremors in the hands as well as other noticeable symptoms of the disease.
Tremors are more common in middle-aged and older adults, although they can occur at any age. There are three types of tremors: resting, postural, and kinetic. Resting tremors occur when the body part is relaxed and supported against gravity on a solid surface. It usually goes away when the individual moves the body part. This type of tremor is commonly seen in Parkinson’s disease.
A postural tremor occurs when holding the extremity against gravity, such as holding the arms out in front of the body. Action or kinetic tremors occur when the body part is intentionally moved, for example when trying to write or pick up an item. Some tremors can be almost unnoticeable; others are debilitating, preventing the individual from performing regular activities of daily living and causing social embarrassment.
The most common tremor is termed “essential tremor”. It is hereditary and occurs in up to 6% of the population. It starts in early adulthood and progresses with age. The tremor is most obvious in the wrist and hands. Other causes of tremor include alterations in blood sugar, thyroid dysfunction, anxiety, inherited metabolic disorders, and tumors.
A host of both prescription and over-the-counter medications can either cause or exacerbate tremors. Well-known drugs like caffeine and pseudoephedrine (found in cold medicines) stimulate the nervous system and can induce tremors. Some asthma and blood pressure medications, as well as certain antidepressants also cause tremulousness.
On the flip side, some drugs can cause tremors when an individual has become dependent on them and then stops taking them all together. Such is the case with alcohol and other drugs of abuse.
Treatment of tremors depends upon the cause. Individuals who are experiencing tremors should receive a physical examination including a thorough neurological exam and medical history from their doctor. Laboratory or imaging studies may be required to exclude certain conditions; however, many of the more common causes of tremors are easily identified with a simple medical history and exam.
The content in this column is for informational purposes only. Consult your physician for appropriate individual treatment. Dr. Reynolds practices Family Medicine in Chesterfield.