Essential tremor

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Tremor is rhythmic oscillation caused by alternating or synchronous muscle activity. Description should specify activation condition, distribution, frequency impression, amplitude, symmetry and associated neurological signs before naming a syndrome. Essential tremor is most visible while maintaining posture or moving towards a target and usually affects both arms. It can involve head, voice, jaw or legs over time. Some patients have additional soft signs and may be described by specialists as essential tremor plus, preserving diagnostic uncertainty rather than forcing another disorder.

The main clinical task is separation from common mimics. Parkinson tremor is typically at rest and accompanied by bradykinesia or rigidity, though re-emergent postural tremor can confuse. Dystonic tremor is irregular, position-specific and associated with subtle abnormal posture, a sensory trick or a null point. Cerebellar tremor increases near a target with dysmetria and gait or eye signs. Enhanced physiological tremor is fine, fast and linked to anxiety, fever, thyrotoxicosis, medicines or withdrawal. Functional tremor changes markedly with distraction or entrainment but requires positive signs and sensitive explanation.

Management is proportional to function. Establish the task the person wants to recover, address amplifiers and offer intermittent or regular medicine only after blood pressure, pulse, airway disease, cognition, falls, pregnancy and interacting treatment are considered. A drug can reduce amplitude without restoring the specific task, so structured before-and-after examples such as handwriting, pouring or using a device matter. Refractory procedures require an experienced movement-disorder and functional-neurosurgery service.

Key points

Essential tremor is an isolated action-tremor syndrome, usually bilateral in the upper limbs, persistent for at least several years and without parkinsonism, cerebellar ataxia or another explanatory neurological sign.
Postural and kinetic components affect writing, pouring, cutlery, cups, tools or presentation tasks; head or voice tremor may occur but isolated head tremor needs careful dystonia review.
The tremor is often asymmetric in amplitude despite bilateral involvement and may worsen with anxiety, fatigue, caffeine, adrenergic medicines and precise goal-directed movement.
A family history is common but not required. Temporary improvement with alcohol is neither specific nor a safe diagnostic or therapeutic strategy.
Look for rest tremor with bradykinesia and rigidity, cerebellar dysmetria, dystonic posturing or a null point, neuropathy, functional variability and enhanced physiological causes before using the essential label.
Review medicines and substances including beta-agonists, valproate, lithium, antidepressants, stimulants, tacrolimus, caffeine and alcohol or benzodiazepine withdrawal.
Thyroid function and other tests are driven by the history; routine brain imaging is not required for a classic stable isolated action tremor.
Treat only when the tremor causes disability, distress or important occupational risk. Propranolol and primidone are common first-line oral choices, selected around comorbidity and preference.
Botulinum toxin can help selected refractory limb, head or voice tremor, while deep-brain stimulation or unilateral focused ultrasound is reserved for severe medication-resistant disability after expert selection.
Occupational adaptation, weighted or stabilising strategies, accessible technology and realistic task-specific goals can offer as much value as a small reduction on a tremor scale.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Familial susceptibility

Essential tremor often clusters in families, suggesting heterogeneous inherited vulnerability rather than one universal causal gene.

Sporadic multifactorial disease

Many affected people have no family history; its absence does not exclude essential tremor when the characteristic clinical syndrome is present.

Physiological modifiers

Anxiety, fatigue, caffeine and adrenergic medicines amplify expression of an established tremor but do not by themselves establish essential tremor.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Rhythmic action tremor
Essential tremor produces rhythmic oscillation during posture and voluntary movement, usually affecting both upper limbs and sometimes the head, voice, jaw or legs.
2
Action-related amplification
Posture and goal-directed movement recruit the unstable network, producing bilateral kinetic and postural tremor most evident during precision tasks.
3
Task-level interference
Increasing oscillation near a target disrupts timing and accuracy of hand, head or voice control despite otherwise preserved power and sensation.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Bilateral upper-limb action tremor

Rhythmic hand movement appears while arms are outstretched and during writing, pouring or finger-nose testing, with one side often more troublesome but neither true bradykinesia nor rigidity.

Head or voice involvement

A yes-yes or no-no head oscillation or regular vocal wavering accompanies longstanding arm tremor. Abnormal neck posture, pain, irregularity or a null point favours dystonia.

Enhanced physiological tremorRed flag

A fine fast symmetrical tremor arises with adrenergic symptoms, fever, anxiety, thyrotoxicosis, excess caffeine, beta-agonists or alcohol withdrawal and improves when the trigger resolves.

Cerebellar or structural clues

Dysmetria, nystagmus, scanning speech, broad gait or a low-frequency intention component indicates cerebellar circuitry and requires a cause beyond essential tremor.

Functional tremor signs

Marked variability, distractibility, entrainment to a voluntary rhythm and incongruent loading response are positive signs of functional tremor, not proof that symptoms are fabricated.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Structured activation examinationFirst step
Why
Classify rest, postural, kinetic, intention and task-specific components and identify associated neurological signs.
Interpretation and limitations
Observe hands in lap, arms outstretched, wing-beating posture, pouring, spiral drawing, handwriting and finger-nose movement; examine tone, repetitive movement, gait, eyes and neck posture.
02
Medicine, stimulant and alcohol history
Why
Find removable tremor amplifiers and recognise withdrawal states that may require urgent treatment.
Interpretation and limitations
Relate onset and dose changes to beta-agonists, antidepressants, lithium, valproate, stimulants, caffeine and immunosuppressants. Ask about alcohol pattern non-judgementally rather than recommending a response test.
03
Targeted blood tests
Why
Exclude metabolic causes when symptoms, age or systemic features make them plausible.
Interpretation and limitations
Thyroid function is common when weight, heat, pulse or anxiety features exist; glucose, electrolytes, liver or renal tests and copper studies in a young person are selected rather than routine for every classic case.
04
Dopamine-transporter SPECT
Why
Resolve persistent specialist uncertainty between essential tremor and a presynaptic degenerative parkinsonian syndrome.
Interpretation and limitations
A normal presynaptic scan supports essential or another non-degenerative tremor; an abnormal scan supports parkinsonism but does not distinguish Parkinson disease from MSA or PSP.
05
MRI brain
Why
Investigate sudden, unilateral, stepwise, cerebellar, pyramidal or otherwise atypical tremor and plan selected procedures.
Interpretation and limitations
Routine stable essential tremor does not require imaging. Interpret incidental white-matter disease cautiously and seek a structural lesion that explains the examination rather than the tremor alone.
06
Functional severity measure
Why
Quantify disability and provide a reproducible target for medicine or procedure evaluation.
Interpretation and limitations
Use a spiral, handwriting, cup transfer, feeding task, occupation-specific activity and patient-rated embarrassment or participation; video with consent can document response.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Parkinsonian tremor

Rest tremor with bradykinesia, rigidity and reduced arm swing favours Parkinson disease, whereas isolated bilateral action tremor supports essential tremor.

Dystonic tremor

Irregular directional tremor with abnormal posture, a null point or sensory trick suggests dystonia, particularly when head tremor is isolated.

Enhanced physiological or drug-induced tremor

Recent beta-agonist, lithium, valproate, stimulant or thyroid-related exposure with fine high-frequency tremor supports a reversible amplifier.

Cerebellar tremor

Low-frequency intention tremor accompanied by dysmetria, nystagmus, dysarthria or gait ataxia indicates cerebellar pathway disease rather than essential tremor.

Additional chapter-specific clues

Parkinsonian alternative

A unilateral pill-rolling rest tremor, reduced arm swing, decrement on finger tapping and rigidity indicates parkinsonism even if tremor also reappears during posture.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Positive diagnosisDescribe before namingFirst stepA patient presents with persistent shaking during posture or purposeful movement.

1Define onset, progression, distribution, activation, task specificity, family history and functional burden, and ask about medicines, caffeine, anxiety, alcohol pattern and withdrawal.
2Demonstrate bilateral action tremor and actively look for bradykinesia, rigidity, dystonia, cerebellar, neuropathic and functional signs; use targeted bloods or imaging only for a clue-led differential.
3When an isolated longstanding action syndrome remains, explain essential tremor and its uncertainty, document baseline tasks and safety-net new rest, gait, cognitive or focal features.

02Function-led treatmentTreat the troublesome taskTremor interferes with eating, writing, work, communication or social participation enough to justify treatment.

1Reduce modifiable amplifiers, provide occupational adaptations and choose one measurable target such as drinking from a cup or performing a professional task.
2Select propranolol if airway, pulse and cardiovascular status permit, or introduce very-low-dose primidone slowly when beta blockade is unsuitable or ineffective.
3Review target-task benefit and adverse effects after titration, stopping an ineffective medicine rather than accumulating sedating combinations; consider topiramate or botulinum toxin only with specialist input.
4For predictable high-stakes occasions, discuss an intermittent plan only if clinically suitable and previously tested safely, not first exposure immediately before the event.

03Severe refractory tremorSelect procedure, target and sideDisabling tremor persists despite tolerated evidence-based medicines and adaptation.

1Confirm the syndrome and medication trials, quantify dominant-hand and bilateral disability, and assess cognition, gait, speech, anaesthetic and MRI suitability in a movement-disorder service.
2Compare adjustable deep-brain stimulation with lesioning approaches such as unilateral MRI-guided focused ultrasound, discussing laterality, reversibility, hardware and speech or gait risks.
3Use a multidisciplinary functional-neurosurgery decision and long-term follow-up; continue occupational strategies because a procedure may improve tremor without eliminating every disability.

Key medicines and prescribing safety5 treatments · regimens, roles and cautions

Reduces upper-limb action-tremor amplitude and can be used regularly or selectively in suitable patients.

Propranolol

A common adult start is 40 mg two or three times daily, titrated by response.

Avoid in asthma, significant bradycardia, heart block or decompensated heart failure; monitor pressure, pulse, fatigue and masking of hypoglycaemia, and do not stop high regular doses abruptly.

Provides an alternative first-line oral treatment when propranolol is ineffective, contraindicated or not preferred.

Primidone

Start very low, often 25 mg at night, and increase gradually under local guidance.

The first doses can cause marked sedation, nausea, dizziness and ataxia; review falls, driving, blood count where indicated, interactions and pregnancy considerations.

May reduce refractory tremor when first-line medicines have failed or cannot be used.

Topiramate

A specialist introduces a low dose and titrates slowly according to benefit and tolerability.

Cognitive slowing, mood change, weight loss, renal stones, glaucoma, metabolic acidosis and major pregnancy-prevention requirements can outweigh motor benefit.

Can treat selected refractory hand, head or voice tremor when targeted weakening improves the priority task.

Botulinum toxin type A

An expert injector selects product, muscles and dose, then repeats according to documented response.

Products are not dose-equivalent; hand weakness, dysphagia or breathy voice may impair function, so anatomical targeting and explicit goals are essential.

Offers adjustable treatment for severe medication-resistant tremor affecting essential daily activities.

Deep-brain stimulation

A specialist team implants and programs thalamic stimulation over repeated postoperative visits.

Consent includes haemorrhage, infection, hardware failure, dysarthria, gait imbalance and stimulation effects; cognition, frailty and bilateral speech risk influence selection.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Loss of hand function

Tremor interferes with eating, drinking, writing, tools, personal care and medication administration, sometimes threatening continued employment.

Voice and social restriction

Head or voice involvement and visible hand tremor can cause embarrassment, avoidance, anxiety and reduced public participation.

Treatment-related morbidity

Oral medicines can cause bradycardia, hypotension, sedation or imbalance, while procedures carry speech, gait, bleeding or hardware-related risks.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Repeat the same handwriting, spiral, pouring and occupation-specific tasks after treatment so a statistically smaller tremor is not mistaken for meaningful functional recovery.
Check pulse, blood pressure, breathlessness, wheeze and fatigue with propranolol and sedation, balance, cognition and driving risk during primidone titration.
Re-examine periodically for new rest tremor, bradykinesia, rigidity, dystonic posture, neuropathy, cerebellar signs or cognitive change that revises the original syndrome.
Review medicine, caffeine, alcohol and anxiety contributions after each new prescription or life change rather than automatically escalating anti-tremor therapy.
After botulinum toxin or a procedure, document task benefit, weakness, speech, swallowing, gait and adverse effects before the next injection or programming change.
Safety-net abrupt onset, new focal deficit, severe gait ataxia, confusion or systemic adrenergic illness for urgent rather than routine tremor review.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Action is the umbrella

Postural and kinetic tremors both occur during muscle activation; describing the precise task avoids using intention tremor inaccurately for every movement-related oscillation.

Alcohol response lacks specificity

Temporary suppression can occur in several tremors and carries tolerance and dependence risk, so it should not be recommended as a diagnostic trial.

Head tremor may be dystonic

Irregular direction, abnormal neck posture, pain, a sensory trick or a position where tremor disappears should redirect examination towards cervical dystonia.

Amplitude is not disability

A small tremor can end a precision career while a large tremor may not trouble another person; the treatment threshold is individual functional impact.

Primidone starts gently

Pronounced first-dose sedation and ataxia are reduced by very-low-night dosing and slow titration rather than beginning near a maintenance dose.

Procedures differ fundamentally

Stimulation is adjustable and involves implanted hardware, whereas focused ultrasound creates a unilateral lesion; laterality and reversibility should be explicit.

11Common pitfallsFrequent interpretation and management errors.

01
Calling any shaking essential tremor without classifying activation and checking for bradykinesia, dystonia or cerebellar signs.
02
Using improvement after alcohol as proof of diagnosis or advice to self-medicate.
03
Prescribing propranolol without asking about asthma, pulse, heart block, diabetes risk and interacting cardiovascular treatment.
04
Starting primidone too rapidly and causing avoidable sedation, nausea, falls or abandonment of a potentially useful medicine.
05
Ordering routine MRI or dopamine-transporter imaging for a classic stable isolated action tremor without diagnostic uncertainty.
06
Referring for lesioning or stimulation before confirming medication resistance, functional target, laterality and speech or gait risk.