My job in the Air Force was to maintain radar, and I worked with all guys. Heavy drinking was very common for airmen. One morning, one of my radar techs came in heavily hung over. So much so, that he was unable to place a screwdriver in a screw head slot because he had the “shakes” so badly. This is an example of drug-induced tremors -- withdrawing from a night of heavy drinking caused his shakes. 

Tremors -- what are they, and what causes them?

What is a tremor and what is its cause? It is an involuntary, unintentional, rhythmic muscle movement that appears as oscillations or to-and-fro movements of the involved body part, such as the hands. It is the rhythmic quality of the tremor that distinguishes the most common form of tremors from other diseases showing abnormal movements. Other parts of the body that may be affected are the arms, face, head, voice, trunk and less frequently, the legs. Tremors may be intermittent or occur all the time. Both sides of the body may or may not be involved. Women and men are equally affected.

Generally, tremors are caused by problems in the brain that control muscles either throughout the body or in specific areas. Multiple sclerosis, traumatic brain injury, stroke or other neurological diseases that damage or destroy brain cells in the brainstem or the cerebellum -- a part of the brain that routes brain signals to the appropriate places and is responsible for coordination and precision -- can cause the shakes.

There are seven different types of tremors: essential, Parkinsonian, dystonic, cerebellar, psychogenic, orthostatic and physiologic. We review four here.

1. Essential tremors (ET) affect up to 10 million Americans. They are the most common form of abnormal muscle tremors. More common in the elderly and usually noticed after age 40, these tremors can start at any age. As people get older, frequency of tremors may decrease, but there may be an increase in the tremors' severity. And though many may think getting tremors is a natural part of the aging process, experts say it is not.

Hands are typically the most affected by ET, but it also can involve trunk, legs, voice, head, tongue or chin. In some, this is a non-progressive disease, but for others, symptoms slowly may progress to involve both sides of the body. These tremors aren’t life threatening, but severe tremors can lead to a disruption in daily activities.

Fifty percent of ET cases are traced to family genetics. There is a fair chance that a child will have tremors as he or she grows older if one or both of his or her parents also have tremors. Though the cause of other incidents of ET isn’t known, there are two theories that attempt to understand the mechanism that makes one’s hands shake. One theory is that there is a mild degeneration of certain parts of the cerebellum. Another theory is that there are abnormal electrical signals that are processed through the thalamus, a deeply buried brain organ that controls muscle activity. These signals are thought to cause tremors.

2. Usually, the first barely noticeable symptom of Parkinson’s disease is a tremor in one hand. It is a progressive illness that slows down movement and promotes stiffness in the body. It is thought that when certain brain cells, or neurons, die, dopamine levels produced by these cells decrease, and that creates abnormal brain activity, which leads to signs of Parkinson’s.

As the disease progresses, more symptoms appear, such as a shuffling gait, stooped posture, muscle pain and/or stiffness, lack of manual dexterity and a slowing down of motor activities. An example of this would be the inability to button a shirt or not swinging one’s arms when walking.  Also, speech may be slurred or slowed, and there may be a loss of facial expression.

3. Enhanced physiologic tremors are similar to essential tremors. These tremors worsen with intense stress and situations with high anxiety. They are also symptomatic of certain diseases such as hyperthyroidism (over-active thyroid) and hypoglycemia (low-blood sugar). And as previously mentioned, alcohol withdrawal along with sedative withdrawal could give you a case of the shakes.
4. Drug-induced tremors are related to the use of stimulants, caffeine, antidepressants and steroids. Often the tremor can be reduced or stopped by either changing the dosing schedule of the drug or the dosing amount. Toxins are also under this category as lead, mercury, and arsenic commonly are found in the environment. Removal of these toxins often stops the tremors after a period of recovery.

Treatment of tremors depends on its cause. Diagnosis is usually based on patient reporting and a series of neurological tests. There is no definitive testing to affirm the diagnosis of some of the tremor types. Treatments can include oral medications, injections and surgery.

Beta blockers, tranquilizers and anti-seizure medications are prescribed to ameliorate the muscle spasms that cause the tremors. Beta-blockers reduce the action of adrenaline on the muscles. Tranquilizers are used in cases of people whose tremors worsen with stress, tension and anxiety. These must be used cautiously because they are habit-forming. Anti-seizure meds typically are prescribed to patients in which beta blockers have no effect.

Botox injections are found to be useful for voice and hand tremors. Each injection’s effects last about three months, but one has to be aware of the side effects. Because Botox is good for reducing hand tremors, it also causes hand weakness. The same is true for the voice box; a shot can cause a hoarse voice and difficulty swallowing.

Surgery for tremors is usually undertaken when symptoms become intolerable or so severe as to interfere with the person’s quality of life. Deep brain stimulation is the implantation of thin electrical leads to the thalamus, a deep brain structure that coordinates muscle control and thought to be involved with ET. Those leads are connected to a neurostimulator device implanted in the patient’s chest that sends painless, electrical impulses to the thalamus to interrupt tremor signals.

You can make lifestyle changes as well. First is the easy stuff like cutting out caffeine, nicotine, alcohol and excessive sugar. Next, tackle emotional or psychological issues that cause you stress. And if you are prescribed medications, take them as prescribed and be patient. It takes time for your mind and body to adjust to, and accept, significant changes.