Essential tumor (ET)-Common movement disorder characterized by a postural tremor of the hands that can be accompanied by tremor in other body parts such as the head, tongue, larynx, trunk or legs.
ET presents with involuntary, rhythmic, hortatory movements, body parts in motion,
Also referred to as benign tremor or familial tremor or shaky hand syndrome.
Cause unknown.
The most common movement disorder.
Most common form of pathologic tremor.
Prevalence as high as 4%.
Estimated to affect approximately 7 million individuals in the US with the prevalence is likely underestimated.
Prevalence is approximately 1% in the general population and 5.9% among persons older than 65 years of age, and greater than 20% among individuals 90 years.
Patients with onset <40 years often have familial ET (82%).
Associates with adverse effects: social isolation, phobia, depression, and interference with work.
The process is not associated with the shorter life expectancy, but does cause difficulty with activities of daily living.
Patients with ET are at increased risk of being diagnosed with Parkinson’s disease(est at 5%).
Population studies suggest a range of prevalence from 0.4-6.3% (Louis ED)
Estimated 10-20,000,000 individuals United States had essential tremor.
Prevalence increases with age.
20 times more common than Parkinson’s disease.
Cause unknown but many have family history consistent with a Mendelian dominant genetic pattern.
Linked to a polymorphism in the gene encoding leucine-rich repeat and immunoglobulin domain containing protein 1 (LINGO).
Characterized by a rhythmic oscillation of agonists and antagonists muscle groups typically between 8-12 Hz.
Symptoms typically be in one upper extremity, and progresses to involve both upper extremities within several years.
Some patients have a mild trimmer that remains stable for decades before symptoms interfere with daily activities.
Functional MRI studies show gray and white matter structural changes to the cerebellum and alterations in connectivity between the cerebellum and various cortical brain areas.
Not a medically dangerous process, but is progressive and disabling.
Patients with ET have an action trimmer.
The tremor occurs with any voluntary movement of the body and includes posture, kinetic, and intention tremors.
Patients with ET rarely have a resting tremor.
Resting tremors are common in Parkinson’s disease and can be accentuated with mental tasks.
Patients often have social phobias and depression.
There are no blood or urine tests to confirm the diagnosis and brain imaging is not indicated for isolated ET.
Treatment:
Nondrug therapies include occupational therapy and adaptive devices that help manage symptoms.
Lifestyle modifications, including caffeine,cessation and avoidance of alcohol overuse can decrease tremor.
Beta-blockers initial treatment.
Medical therapy is often successful.
Up to 50% of patients with essential tremor cannot tolerate therapeutic medications or have refractory tremor.
Effectively treated with propranolol and primidone.
Use of propanolol decreases limb tremors by 50 to 70%.
A combination of primidone and propranolol may be more effective than either medication alone.
30 to 50% of patients with the ET do not improve with these medications.
Topiramate decreases tremor and improves activities of daily living in 3 of 4 clinical trial patients.
Alcohol can diminish tremor in many patients.
Deep brain stimulation surgical treatment of choice, with a 70-90% tremor control.
Treatment of head and voice tremor with deep brain stimulation is less effective.
Ventralis intermedius nucleus to the thalamus is the most appropriate target for treatment.
Deep brain stimulatory devices can be applied to the thalamus.
An association exists for essential tremor and spasmodic dysphonia with a 79% female preponderance.
Botulinum toxin type A is effective to varying degrees in the treatment of essential limb trimmer, prevents the release of acetylcholine in synapses, leads to reduction in aberrant muscle movement.
The injection of botulinum toxin into the splenius capitis muscle is more effective than placebo in reducing the severity of isolated or essential head tremor at 18 weeks, but not at 24 weeks, and is associated with adverse effects, including head and neck pain, posterior cervical weakness, and dysphagia (Marqvues A).
Botulinum may be effective in ET that affects the voice, chin and jaw.