Definition and Causes:

A disorder characterized by the uncontrollable shaking (tremor) of the hands and arms and sometimes may also involve the legs, trunk, head, voice, and chin. It is the most common of all movement disorders. The degree of severity of symptoms is variable among affected people. The condition is usually progressive and hereditary, and almost always improves with the ingestion of alcohol.

Types of Essential Tremors

• Benign essential tremor: No genetic link (non-hereditary)
• Familial Tremor: Family history of tremors (inherited)

Causes

• The exact cause for essential tremor is unknown. Tremors occur when there is a problem with the nerves; which is enclosed cable-like bundle of axon (slender projection of a nerve cell also called as neuron); that supply certain muscles
• If an essential tremor (ET) occurs in more than one member of a family, it is called a familial tremor. This type of essential tremor is passed down through families (inherited), which suggests that genes (unit of heredity of a living organism) play a role in its cause
• In approximately half of the cases, essential tremor is inherited. Several different genetic defects may play a role in this condition. Essential tremors (ET) are most common in people older than 65

Note: The uncontrollable shaking associated with essential tremors (ET) is not unique to this condition. Many different factors or diseases can also cause tremors, including Parkinson’s disease, multiple sclerosis, fatigue after exercise, extreme emotional distress, brain tumors, some prescription drugs, metabolic abnormalities, (change in the blood level of some chemicals such as hormones or minerals e.g. sodium) and alcohol or drug withdrawal.

Symptoms:

The tremor is more likely to be noticed in the hands but may affect the arms, head, eyelids, or other muscles. The tremor rarely affects the legs or feet. The tremors are increased when the patient is focusing on something or concentrating to perform an action such as using a fork, holding a cup or writing with a pen. Shaking most often involves small, rapid movements (more than 5 times a second) and is increased with emotional excitement (e.g. being the center of attention at a party). Essential tremors (ET) differ from the tremors seen in Parkinson’s disease, which tends to produce a resting tremor, i.e. shaking of the hands while sitting calmly.

Specific essential tremors (ET) symptoms may include:

• Head tremor (nodding or side to side movements)
• Shaking or quivering sound to the voice if the muscles controlling the vocal cords are affected
• Problems with writing, drawing, drinking from a cup or using tools if the tremor affects the hands

The tremors may:

• Occur with movement (action-related tremor), and may be less noticeable with rest
• Comes and go, but often gradually worsens with age
• Worsens with stress, caffeine, and certain medications

Investigations and Treatment:

A detailed history is required including:

• Family history
• Duration (how long has it been there)
• Severity of the tremor (e.g. is writing or fastening buttons affected)
• Parts of the body involved
• Relieving or exacerbating factors
• Review of patient’s medications
• Inquire about any illicit drug use/abuse

A physical exam will often show shaking movements, especially when limbs are placed in certain positions (e.g. outstretched arms). There are usually no problems with coordination or mental function.

Further tests may be needed to rule out other reasons for the tremors.

Other causes of tremors may include:

• Smoking and smokeless (chewing) tobacco
• Overactive thyroid (hyperthyroidism)
• Excess alcohol consumption or suddenly stopping alcohol after drinking a lot for a long time (alcohol withdrawal)
• Excess caffeine consumption
• Use of certain medications

Blood tests and imaging studies such as a CT or MRI scan of the brain are usually normal and are only done to exclude other diseases, if suspected.

TREATMENT:

Treatment may not be needed unless the tremors interfere with the daily activities of living or cause embarrassment.

Patients may be advised to:

• Avoid factors that may worsen tremor including stress; adopt relaxation techniques
• Avoid caffeine, nicotine and other stimulants
• Consult occupational therapist regarding adaptive devices for performing daily activities
• Get adequate rest/ sleep
• Use clothing with velcro fasteners
• Cooking or eating with utensils that have a larger handle
• Avoid excess use of alcohol to “control” symptoms and seek appropriate medical therapy for worsening symptoms
• For tremors caused or made worse by a medication, talk to your doctor about stopping the drug, reducing the dosage, or switching. DO NOT change or stop medications on your own
• Seek additional information/education and resources to better understand the condition and help achieve adequate control on tremors

Medications

• Beta-blockers (e.g. propranolol) may provide some relief in 60-80% of cases
• Primidone may be tried in those who may not respond to beta-blockers or who are unable to tolerate or use beta blockers. In some patients, it may offer up to 50-60% of the benefit
• Patients requiring intermittent control of tremors in social settings may use small quantities of beer or wine prior to the activity, though it is NOT recommended for maintenance therapy

The most commonly used drugs include:

Surgery:

In severe cases, surgery may be tried. This may include:

• Deep brain stimulation: In selected cases, a stimulating device can be implanted into a specific area of the brain that is thought to be causing the essential tremor

• Focusing high-powered x-rays on a small area of the brain (stereotactic radiosurgery) procedure carries a small risk of major complications

Risk Factors and Prevention:

• Exact cause is unknown, there is currently no way to prevent it. However, knowing that essential tremor (ET) has a genetic link requires a further search for effective treatments and, ultimately, ways to prevent it

• Alcoholic beverages in small quantities may decrease tremors but can lead to alcohol dependence and alcohol abuse, especially if there is a family history of such problems

Outcome:

Essential tremor is not a dangerous problem, but some patients find tremors annoying and embarrassing. Some patients, however, may progress to disabling tremors. In general, most have mild to moderate tremors that are not severe enough to interfere with usual activities such as work, writing, eating, drinking, or can be at least partially controlled with medications to allow the relatively normal activity.

Complications:

Sometimes the tremors affect the vocal cords which occasionally lead to speech problems.