Description
• Involuntary rhythmic and oscillatory movements of body part due to alternating contraction of opposing muscle groups not resulting from other disease or medication
— Typically involves hands and forearms
— Can present as isolated tremor of head
— Not associated with abnormal posturing
Also called
• Senile tremor
• Benign essential tremor
• Familial tremor
• Kinetic tremor—occurs during movement
• Postural tremor—occurs when body part is held against gravity (e.g., arms outstretched)
• Action tremor
• Intention tremor—tremor that intensifies as it reaches a target, e.g., pointing to nose
ICD-9 code
• 333.1 Essential and other specified forms of tremor
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Prevalence
• Prevalence estimates range from 0.1% to 22%, with most common estimated prevalence about 4% in older adults.
• Mean age of onset 52 years
• 53% male, 47% female
• Mean age of onset 8.8 years in patients with childhood-onset essential tremor
Cause
• Unknown
Presentation
• Tremor often of flexion/extension type
• Occurs during voluntary movements
• Impaired performance of motor tasks
• Tremor frequency usually 4-12 Hz
• Patients often embarrassed by change in handwriting or difficulties with eating soup or drinking from full glass or cup due to spillage
• May be exacerbated by stress (physical and/or emotional), caffeine, sleep deprivation
• May be suppressed by alcohol
• Hands and arms commonly affected
• May have tremor of head (75% of head tremors are “no-no” type), jaw, facial muscles, tongue, and/or voice
• Rare involvement of lower extremities
• Eliciting tremor on exam
— Postural tremor seen with outstretched arms
— Kinetic tremor brought on by writing or with finger to finger to nose as patient approaches final target
• Look for resting tremor, bradykinesia, rigidity (features of Parkinson’s disease rather than essential tremor).
Diagnosis
• Clinical diagnosis based on history and physical exam
• Most common tremor disorder but often misdiagnosed
• Rule out
— Enhanced physiologic tremor
— Spasmodic torticollis
— Hyperthyroidism
— Parkinson’s disease
— Psychogenic tremor (likely disappears with distraction)
— Dystonia
— Wilson’s disease
— Medication-induced tremor
• Testing
— Thyroid function (thyroid-stimulating hormone) for hyperthyroidism
— Rule out Wilson’s disease (ceruloplasmin, serum copper, liver function tests) in patients <40 years old.
Prognosis
• Once termed “benign” but can lead to disability
• Tremor amplitude increases, but frequency decreases with age.
Treatment
• First-line medication therapies—start at low dose and increase slowly
— Propranolol (Inderal) 60-800 mg/day or sustained-release propranolol (Inderal LA) 80-320 mg/day may improve clinical scores and self-reported severity.
— Primidone (Mysoline)
♦ 50-1,000 mg/day appears effective for hand tremor in small trials.
♦ Primidone 250 mg/day appears as effective as and better tolerated than primidone 750 mg/day.
♦ Primidone may be more effective than propranolol for kinetic and intention tremors.
• Other medications to consider
— Limited evidence on other available beta blockers
— Topiramate (Topamax) (up to 400 mg/day) associated with modest improvement in essential tremor
— Gabapentin (Neurontin) may improve essential tremor, but evidence limited and inconsistent
— Olanzapine (Zyprexa) 20 mg daily may improve tremor more than propranolol.
• Botulinum toxin type A (Botox) injections may improve postural but not kinetic tremors; high rate of hand weakness
• Surgical therapies considered possibly effective
— Chronic thalamic deep brain stimulation for hand tremor (FDA-approved)
— Thalamotomy (creating a lesion in ventral intermediate nucleus of thalamus)
— Thalamic stimulation appears to be as effective as thalamotomy, with fewer adverse effects.
— Bilateral thalamic deep brain stimulation may be more effective than unilateral deep brain stimulation in controlling bilateral limb and midline tremors.
• Patients often self-medicate with alcohol.
For references, see www.dynamicmedical.com.
Dr. Brown is a neurologist and deputy editor for DynaMed (www.dynamicmedical.com), a database of comprehensive updated summaries covering nearly 3,000 clinical topics. Dr. Pham is a Master Teacher Fellow, Tufts University Family Medicine Residency, Cambridge Health Alliance’s Malden Family Medicine Center, Malden, Mass., and a peer reviewer for DynaMed.
This article originally appeared on Cancer Therapy Advisor
