DEAR DOCTOR K: My mother’s hands are shaking more than usual lately. She has made an appointment with her doctor, but in the meantime, can you tell me if shaking is always a sign of something serious like Parkinson’s disease?
DEAR READER: The shaking in your mother’s hands is called a tremor. Tremors can affect the hands, limbs, head or voice. The actress Katharine Hepburn developed tremors of her head and voice in her later years. A person can’t control a tremor.
Most of us can get temporary tremors as a normal reaction to fear, anger, or when we are simply too tired or worn out. Too much caffeine or nicotine (in heavy smokers) can cause a tremor. So can withdrawal from an addictive substance (powerful painkillers or alcohol). Many commonly prescribed drugs also can cause a tremor. Examples include drugs used to treat depression such as selective serotonin reuptake inhibitors, tricyclics and lithium; the asthma drugs terbutaline and theophylline; and potent anti-inflammatory drugs such as prednisone. Lowering the dose of these medicines may reduce the tremor.
One fairly common disease, hyperthyroidism (overactive thyroid) can cause tremor. A patient of mine who came for an annual checkup said her hands had started shaking. She also had a rapid heart rate, even at rest. I ordered blood tests that confirmed she had hyperthyroidism. Treatment fixed her thyroid, and her tremor.
Two other common kinds of tremor are essential tremor and Parkinsonism. Like you, many of my patients with a tremor worry that they have Parkinson’s disease, but essential tremor is much more common.
It is usually easy to tell the difference. Essential tremor is most noticeable when a person is in action. It can come on when someone is doing everyday things like writing a note or pouring a glass of iced tea. It’s the opposite with the tremors of Parkinson’s disease. The tremors occur at rest, as when a person is sitting still with her hands in her lap. But when she reaches out to grab or hold something, the shaking stops.
There are other symptoms that help to tell the difference. With Parkinson’s, it is more common for the tremors to start on one side of the body. Also, it is more common for tremors to involve the legs and to make walking difficult. Finally, people with Parkinson’s lose facial expression: They don’t smile much, or show much emotion in the face.
One thing that has helped me diagnose essential tremor in the past may sound a bit odd. The fact is that an alcoholic drink can stop the tremor for an hour or so. So if this works, it may be essential tremor. No, I am not recommending a drink per hour as treatment of essential tremor! Instead, there are two medications that can help control essential tremor: propranolol and primidone, which produce chemical reactions similar to those caused by alcohol.
Only your mother’s doctor can correctly diagnose the cause of her tremors. Fortunately, most tremors are not caused by Parkinson’s disease and can be successfully treated.