Essential tremor

Overview

•Bilateral postural and kinetic (action) tremor - absent or minimal at rest; worsens with arms outstretched or on intentional movement

•Frequency 6-12 Hz - classic exam range 6-8 Hz

•Functional impairment - writing, using utensils, holding a cup

•Family history - ~50% of cases; autosomal dominant inheritance

•Relieved by alcohol - in ~65% of patients

•Exacerbated by - anxiety, caffeine, adrenergic stimulation

•Head tremor - horizontal ('no-no') in 75%, vertical ('yes-yes') in 25%

🎯
Essential tremor is absent at rest and worsens on action. Parkinson's tremor is most prominent at rest and often improves on intentional movement - the opposite pattern.

Investigations

Essential tremor is a clinical diagnosis - investigations are used to exclude other causes.

🥇 First-line

•thyroid function tests (exclude hyperthyroidism), renal/liver function, medication review (lithium, valproate, amiodarone, SSRIs, TCAs)

•If Parkinson's disease cannot be excluded clinically: DaTscan (SPECT) - normal in essential tremor, reduced dopaminergic uptake in Parkinson's disease; ordered by specialist, not first-line in primary care

•If younger patient with liver disease or psychiatric features: serum caeruloplasmin/copper and slit-lamp examination to exclude Wilson's disease

🚨
Suspected Parkinson's disease (resting tremor, bradykinesia, rigidity) should be referred urgently to a specialist with expertise in movement disorders - do not start treatment in primary care.

Differential diagnosis

Essential tremor vs Parkinson's disease vs Cerebellar tremor
FeatureEssential tremorParkinson's diseaseCerebellar tremor
TypePostural/kinetic (action)Resting tremorIntention tremor
Frequency6-12 Hz4-6 Hz3-4 Hz
At restAbsentPresentAbsent
On movementWorsensImprovesWorsens (dysmetria, past-pointing)
Other signsNone (no bradykinesia/rigidity)Bradykinesia, rigidity, shuffling gaitAtaxia, dysdiadochokinesia, wide-based gait
Family historyCommon (~50%)Usually sporadicVariable

Feature	Essential tremor	Parkinson's disease	Cerebellar tremor
Type	Postural/kinetic (action)	Resting tremor	Intention tremor
Frequency	6-12 Hz	4-6 Hz	3-4 Hz
At rest	Absent	Present	Absent
On movement	Worsens	Improves	Worsens (dysmetria, past-pointing)
Other signs	None (no bradykinesia/rigidity)	Bradykinesia, rigidity, shuffling gait	Ataxia, dysdiadochokinesia, wide-based gait
Family history	Common (~50%)	Usually sporadic	Variable

Management

🥇 First-line

•propranolol 20-40 mg twice daily - non-selective beta-blocker; reduces tremor amplitude by blocking peripheral beta-2 adrenergic receptors

🥈 Second-line

•primidone - anticonvulsant metabolised to phenobarbitone; use if propranolol is contraindicated (asthma, significant bradycardia, heart block)

•Second-line alternative: gabapentin - GABAergic agent; alternative or adjunct when first-line agents fail

🥉 Third-line

•botulinum toxin injections (isolated head/voice tremor) or deep brain stimulation of the ventral intermediate nucleus of the thalamus (severe, refractory cases)

⚠️
Benzodiazepines (e.g. diazepam) are NOT recommended as regular treatment due to dependence risk and sedation - they may be used occasionally for situational relief only.