Patients frequently come to see me for evaluation of their tremor. Invariably the history is that the tremor was first brought to their attention by a close friend or a family member. The patient is worried that he/she has Parkinson’s disease and hence seek a neurologist’ s attention. Rarely are they bothered by the tremor per-se. By that I mean the tremor is usually not disabling and does not impair their quality of life at least initially. So do all tremors represent Parkinson’s disease? Are there any benign tremors? Which tremors warrant medical attention? These are some of the issues I plan to dwell on in this blog post. I hope some of my readers shall find the information useful.
So what exactly is a tremor. Well neurologically a tremor is characterized by rhythmic oscillatory and involuntary movement across a joint. I used the work involuntary because tremors at times can be voluntary. Voluntary tremor is usually psychogenic (meaning it has a psychological basis to it). We shall not discuss psychogenic/voluntary tremors in this post though. Suffice to say that a doctor shall be able to identify psychogenic tremor based on the history and examination findings alone.
So what do I look for when a patient with tremor comes to me seeking an explanation. Well the age of the patient is the first clue to the etiology of the tremor. Idiopathic Parkinson’s disease usually starts off in the sixth to seventh decade of life. Familial Parkinson’s disease can start at a younger age but usually the tremor is not so prominent nor is it the initial manifestation. There can be many causes of tremor in the “young”. Various medical conditions some more common such as hyperthyroidism, hepatic and renal diseases and some more exotic such as Wilson’s disease (due to a problem with copper metabolism in the body)come to mind. At times the answer is more innocuous and the tremor is either due to stress or excessive intake of coffee and other caffeine containing drinks. In that case all that is needed is reassurance. One other disease that needs to be kept in mind is multiple sclerosis though usually more findings are documented in exam (meaning that the tremor is not see in isolation). One should never forget to ask patients about the use of prescription, over the counter and illicit drugs. Many drugs such as sodium valproate (commonly used to treat seizures and at times bipolar disorder), bronchodilators (drugs used to treat asthma, reactive airway disease and chronic obstructive airway disease) cause a coarse postural and kinetic tremor as a side-effect. Once the drug is stopped the tremor abates.
Another common entity frequently confused with Parkinson’s disease is what is called essential tremor or also sometimes referred to as benign essential tremor. Patients who have essential tremor are usually in the same age group as patients with idiopathic Parkinson’s disease and hence the confusion and concern arises. Essential tremor has the following characteristics: it is usually a postural tremor (meaning that the tremor is most prominent when the hands are kept out and maintained at a posture such as having them stretched out in front of you. Remember the classical tremor of Parkinson’s disease is a resting tremor. Meaning the tremor is most prominent when the hands are at rest like for example resting on the patient’s lap and the patient’s attention is diverted). Essential tremor is a faster and finer tremor as compared to the tremor of Parkinson’s disease which is a slower (2-5 Hz) and of higher amplitude. A point to note here is that tremors are frequently classified based on their frequency, amplitude and position (rest Vs postural Vs kinetic). Patients who have essential tremor frequently in addition to the hand tremor also may have a head tremor (the head shakes either from side to side [no-no tremor] or up and down [yes-yes tremor]). They may also have a tremor in their speech (voice tremor). On further questioning some of them may admit to having the tremor run in their family (meaning their father and grandfather also had a similar tremor). They may have also noted that when they drink alcohol the tremor becomes less prominent. Infact some patients start drinking excessively for this very reason! Essential tremor usually progresses very very slowly (if at all) and may never become problematic and disabling in the patient’s lifetime. Hence it does not need to be treated unless it is socially disabling (“Doctor Sethi I cannot drink a glass of wine without spilling it over my dress!” “Dr Sethi I am so embrassed when my hands shake in a business meeting!”). Essential tremor is not accompanied by the other signs and symptoms which accompany Parkinson’s disease such as gait problems, freezing, stiffness, rigidity and mask like facies.
So not all tremors represent Parkinson’s disease. A quick visit to your “local” neurologist shall give you an answer to what kind of tremor you have.
Another of my readers emailed me this question. My response to it follows:
on October 16, 2008 said:
I’ve been having tremors over the past 4 months in my hands, feet and legs, and lips. They are more prominent (especially in my hands) after exercise. My physician did blood work and it indicated I was “mildly” hyperthyroid (slightly low TSH, normal T3/T4). He blames the tremors on this condition. He has prescribed propranolol 20mg BID for the tremors, but wants to wait and see if the thyroid might correct itself before putting me on Methimazole (due to its side effects). My symptoms seem rather profound for a “mild” case of hyperthyroidism. Do you have any further suggestions or input?
thank you writing in. As I stated in my earlier post on tremors (you can read my post at my website http://braindiseases.info ) tremors can be of various kinds. The kind of tremors you are describing when your hands are outstretched (but you also have them in your feet and lips) are likely not due to a neurological condition per-se. We all have a subtle tremor in our hands, this is called physiological tremor. If you make people hold their hands out in front of you, you shall be able to notice it is you pay close attention. Now suppose this person goes and drinks 6 cups of large Starbucks coffee and you again make him or her stretch their arms in front of you, the tremor shall be more prominent. This is called enchanced physiological tremor. As the name says, these tremors are physiological and not pathological (we all have them, some more prominently than others).
There are certain medical conditions which may cause tremors or make the physiological tremor more prominent. One such condition is hyperthyroidism. Patients who have hyperthyroidism do have tremors of their hands and also of their tongue (if you make them stick their tongue out, you shall be able to notice the tremor). Some medicines and drugs of abuse also cause tremors. Patients who drink alcohol heavily are tremulous, especially if they stop drinking suddenly.
Not all tremors need to be treated. We only treat a tremor if it becomes disabling for a patient or causes social embrassement. Propanolol (a beta blocker drug used as an anti-hypertensive medication) does have a role in treating postural tremors. Your doctor may like to slowly taper the dose up and see if it gives you any relief. I cannot comment if hyperthyroidism indeed is the cause of your tremor. As you can see from what I wrote above there can be protean causes of tremor some neurological (neurodegenerative in etiology like Parkinsos’s disease), other more benign (Benign Essential Tremor) and toxic/ metabolic causes of tremors (hyperthyroidism, drug induced tremors etc).
My advise to you would be to follow your doctors instructions and see if the propanolol gives you benefit. As I stated earlier, he has started you on a low dose and may taper it up over a period of time. If this tremor does not subside, then you may need a neurological work-up to try to determine the etiology of the tremor.
Please feel free to write in again.
Nitin Sethi, MD
So let us discuss the diseases which can present with tremors.
1) Drug induced tremors: certain drugs can induce a tremor like I stated ealier. Drugs used to treat asthma (inhalers) and anti-epileptic drugs like valproic acid may induce a tremor in the hands.
2) Benign essential tremor: this as the name suggests is a benign tremor. Patients who have benign essential tremor usually have a postural tremor in their hands but may also have a head and speech tremor. They do not have any underlying neurodegenerative disorder and usually the tremor is not disabling and progressive. As the tremor is not disabling it may not need to be treated unless it causes social embrassement to the patient. Patients who have classical essential tremor notice that their tremor becomes less prominent if they consume alcohol (tremor is alcohol responsive).
3) Cerebellar tremor: patients who have cerebellar involvement (example if you have cerebellar tumor or diseases that involve the cerebellum such as multiple sclerosis) may also have a prominent kinetic (intentional) tremor.
4) Parkinson’s disease: patients who have Parkinson’s disease have a prominent resting tremor. This tremor is most prominent when their hands are at rest and becomes less prominent when they start to use their hands.
Treatment of tremors: like I mentioned earlier, not all tremors need to be treated. We usually treat tremors when they become disabling or socially embrassing to the patient. There are different classes of drugs that are effective for tremor of Parkinson’s disease, cerebellar tremor and essential tremor. Your doctor shall help in deciding what kind of medication may work the best for you. Sometimes if the tremor is particularly disabling and unresponsive to medication, it may respond to neurostimulation (deep brain stimulation). I shall discuss this in a separate post.
In this post I shall talk a little bit about tremors. What exactly is a tremor you may ask. The way we define tremor in neurology is a rhythmic oscillatory movement across a joint. One may have a hand tremor (your hands shake), leg tremors, head tremor and even speech and tongue tremors. One way to classify tremors is to divide them into physiological and non-physiological tremor.
Physiological tremor is present in each and every one of us. If you hold your hands straight out and balance a sheet of paper on it, you can see the paper shaking a little. This is due to the physiological tremor in our hands. We all have it and the thinking behind it is that it is due to cardioballistic motion. Now suppose you go and have a large (I think they call it venti size) Starbucks coffee and repeat the above test again. You shall find that your tremor is now more prominent, this enhancement of the physiological tremor by coffee and some drugs like aminophylline is what is called enhanced physiological tremor. Physiological and enhanced physiological tremors do not need to be treated as they do not disturb the patient in any way. You may ask the patient to cut down on his coffee though.
Non-physiological tremor: as the name suggests these tremors are pathological. One way to classify pathological tremors is on the basis of how they present. So one may have a tremor which is most prominent when the hands are completely at rest and is not present once the hands come into motion (or start doing some activity). This is called a resting tremor (tremor at rest) and is classically seen in patients with Parkinson’s disease. Other tremors are prominent only when the hand is engaged in some action and hence those tremors are called action tremor.
When a patient comes to us for the evaluation of a tremor what we look for is whether the tremor is isolated (meaning there are no other manifestations apart from the tremor) or whether the tremor is a part of a larger neurological syndrome. We want to rule out neurodegenerative conditions like Parkinson’s disease which may present with tremor. Secondly we want to know whether the tremor shall remain static or whether it is going to worsen as time goes by. Then we try to classify the type of tremor and try to identify its etiology. Is it drug induced? What are its exacerrbating factors and what factors make the tremor become less prominent? Does the tremor become less prominent after consuming alcohol? Does the tremor run in the family (meaning is there a family history of tremors)? What does the tremor involve: just the limbs or also the head and speech?
In my next post I shall talk about the management of tremors.