Trembling (tremor): causes, diagnosis and what really helps

What does trembling really mean? Causes from essential tremor to Parkinson's, the thyroid and medications, tests, therapy and when to see a doctor.

1. What is trembling?

Trembling — medically tremor — is an involuntary, rhythmic muscle movement that usually occurs in the hands but can also affect the head, legs, voice or trunk. Tremor is not a single condition but a symptom with very different causes — from completely harmless to an indication of a serious neurological disease.

The distinction between physiological and pathological trembling is important. Slight trembling with cold, agitation, physical exertion, tiredness or after coffee is part of the normal human reaction and does not need treatment. Trembling only becomes pathological when it occurs in everyday life, persists without a recognisable trigger, increases, is asymmetric or noticeably restricts quality of life.

About 1 per cent of adults have an essential tremor — from the age of 65 it is even up to 5 per cent. Parkinson's disease affects about 400,000 people in Germany, with a tendency to further increase through the ageing of the population. Tremor is thereby one of the most common neurological symptoms of all — and at the same time one of the most frequently misdiagnosed.

2. Tremor types: resting, action and postural tremor

The most important clinical distinction — it considerably narrows down the causes already at the first examination — is the situation in which the trembling occurs.

Resting tremor

Occurs when the affected body part is relaxed — for example when sitting with the hands resting on the thighs. With movement the tremor subsides. The resting tremor is the classic leading symptom of Parkinson's disease and typically occurs on one side, often with the characteristic 'pill-rolling' pattern between thumb and index finger.

Action tremor

Occurs when the affected body part is moved — for example when grasping, drinking from a glass, writing or doing up buttons. The action tremor is the leading symptom of essential tremor, typically occurs on both sides and is symmetric.

Postural tremor

Occurs when the affected body part has to actively hold a position — for example when holding the arms outstretched. This too is typical of essential tremor but also occurs with an overactive thyroid, hypoglycaemia, medication side effects and alcohol withdrawal.

Intention tremor

A special form of the action tremor — the trembling increases the closer you get to the target (e.g. in the finger-to-nose test). Typical of diseases of the cerebellum, for example with multiple sclerosis, a cerebellar stroke or hereditary ataxias. A prompt neurological assessment is important here.

Orthostatic tremor

A rare, very fast trembling (13–18 Hz) of the legs that occurs only when standing and disappears when sitting or walking. Those affected often report the feeling of not being able to keep themselves securely on their legs — the tremor itself is usually not visible but can be palpable. Onset usually in middle age.

3. Physiological trembling: harmless and normal

Every person has a physiological trembling with a very fine amplitude and a frequency of 8 to 12 hertz — usually not visible but measurable at any time. Under certain conditions this trembling can be intensified:

• Stress, agitation, stage fright — sympathetic activation increases muscle activity
• Cold — muscle trembling serves heat production
• Exertion and exhaustion — muscle fatigue leads to unrhythmic contractions
• Caffeine, nicotine, energy drinks — a direct stimulating effect
• Lack of sleep — intensifies almost every form of tremor
• Low blood sugar without diabetes — e.g. with long fasting or after intense exertion
• Fever and shivering — heat regulation

These triggers are harmless, temporary and need no medical assessment — as long as the trembling subsides after the cause is removed. Important to know: an intensified physiological tremor can also become permanent through medications, states of stress or an overactive thyroid.

4. Essential tremor: the most common tremor condition

Essential tremor is by far the most common tremor condition and affects about 1 per cent of adults, from age 65 even up to 5 per cent. It is inherited in 30 to 70 per cent of cases — when one parent is affected, the risk is around 50 per cent. Despite its frequency it is often misdiagnosed or mistaken for Parkinson's.

Typical features: a bilateral action and postural tremor, usually in the hands — lifting a cup, writing, eating with a spoon becomes laborious. In about half of cases the head is also affected (yes-yes or no-no movements), more rarely the voice or legs. The frequency is 5 to 12 Hz. Characteristic is the improvement under alcohol — about 60 to 80 per cent of those affected report a marked short-term decrease in symptoms after a glass of wine or beer. That is an important diagnostic indication but of course not a treatment approach.

Course: essential tremor usually begins in young or middle adulthood but can also begin in childhood or only in old age. It increases slowly over years but is not prognosis-limiting. About half of those affected develop a marked impairment of everyday functions over the course.

Important distinction from Parkinson's: essential tremor is an action tremor (occurs with movement), Parkinson's tremor is a resting tremor (occurs in relaxation). Essential tremor is symmetric on both sides, Parkinson's asymmetric and emphasised on one side. With essential tremor the typical Parkinson's symptoms such as slowing of movement (bradykinesia), muscle stiffness (rigidity) and gait disorders are absent.

5. Parkinson's disease and parkinsonian syndromes

Parkinson's disease is the second most common neurodegenerative disease after Alzheimer's dementia. It typically begins between the ages of 50 and 70 but can also occur earlier (young-onset Parkinson's). The classic clinical picture comprises four cardinal symptoms:

• Resting tremor: typically beginning on one side, 4–6 Hz, 'pill-rolling' movement — in about 70 per cent of patients as the first symptom
• Bradykinesia: slowing of movement, reduced facial expression (masked face), small handwriting (micrographia), an increasingly quiet voice
• Rigidity: muscle stiffness, 'cogwheel phenomenon' with passive movement
• Postural instability: a gait disorder with small-stepped shuffling walking, a tendency to fall — usually only in later stages

Early signs that can precede the motor manifestation by years: loss of smell (smell disorder), REM sleep behaviour disorder with dreams, mood swings and depression, constipation, slight cognitive changes.

Parkinson-plus syndromes: atypical forms such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) — they usually run a faster course and respond less well to standard therapy. A specialist differential diagnosis is decisive.

6. An overactive thyroid and hormonal causes

An overactive thyroid is one of the most common and readily treatable causes of an intensified postural tremor — and is nevertheless often overlooked. Typical accompanying symptoms: sweating, palpitations, unintentional weight loss, inner restlessness, sleep disorders, diarrhoea, heat intolerance. A simple blood test (TSH, fT3, fT4) clarifies the suspicion — it should be standard with every newly arisen tremor.

Further hormonal causes: phaeochromocytoma (a very rare hormone-producing adrenal tumour with attacks of high blood pressure and sweating), carcinoid syndrome, hypoglycaemia with diabetes (see next chapter). During the menopause too, intensified trembling is occasionally observed, usually in connection with hot flushes and lack of sleep.

7. Trembling from low blood sugar with diabetes

In people with diabetes — above all on insulin or sulfonylureas such as glibenclamide — low blood sugar can trigger acute trembling. Typical constellation: suddenly setting-in fine trembling of the hands, sweating, ravenous hunger, heart palpitations, concentration difficulties, irritability. The treatment is simple: fast-acting carbohydrates (glucose, a sugary drink), followed by complex carbohydrates.

Important constellation: non-diabetics too can develop mild hypoglycaemic symptoms with long breaks without food or after intense exertion — usually harmless. Repeated episodes with disturbed consciousness, on the other hand, need investigation (insulinoma, hormonal disorders).

8. Anxiety, stress and psychogenic tremor

Acute stress, anxiety disorders, panic attacks or social phobia can cause a pronounced intensified physiological tremor — typically in the hands and legs, often accompanied by palpitations, sweating, a feeling of tightness and inner restlessness. The trembling often intensifies in situations where it 'should not happen' — when speaking in front of people, when writing in public — and thereby itself becomes a source of stress.

A special form is the psychogenic or functional tremor — it often has a changing frequency and amplitude, is influenced by directing attention and sometimes occurs after stressful life events. The diagnosis is made by experienced neurologists, often with specialised tests, and belongs in psychotherapeutic or behavioural-medicine hands — not in the 'imagined' drawer.

9. Alcohol and drug withdrawal

A pronounced morning tremor that is improved by alcohol is a classic indicator of alcohol dependence — even if those affected often do not perceive it that way themselves. With sudden cessation, a pronounced alcohol withdrawal tremor can occur, often accompanied by sweating, nausea, high blood pressure, irritability and insomnia.

Withdrawal from benzodiazepines (sleeping pills, sedatives) and opioids too can lead to trembling and belongs in medical hands. Substitution with shorter-acting substances and a step-by-step reduction are established.

10. When to see a doctor? (warning signs)

Have it assessed by a doctor promptly if:

• newly arisen trembling without a recognisable trigger
• one-sided or markedly asymmetric trembling
• trembling at rest (a typical suspicion of Parkinson's disease)
• accompanying movement disorders: slowing of movement, gait unsteadiness, small handwriting, a quiet voice
• trembling with other neurological symptoms: weakness, sensory disturbances, visual disturbances, speech problems
• trembling in combination with sweating, weight loss, palpitations, restlessness (suspected thyroid)
• recurrent hypoglycaemia — especially with diabetes
• trembling after a change of medication or a new prescription
• considerable impairment in everyday life, social withdrawal, depressed mood
• a tremor with markedly changing amplitude (suspected functional tremor)

11. Diagnostics: what the neurologist does

The diagnostics of tremor are clinical — an experienced neurological examination leads to the correct diagnosis in the vast majority of cases. Imaging and laboratory serve confirmation and differential diagnosis:

• History: onset, course, triggers, time of day, asymmetry, family history, medications, lifestyle, alcohol/drug consumption
• Neurological examination: range of movement, muscle tone (rigidity?), bradykinesia tests, finger-to-nose test, gait pattern, handwriting and spiral test
• Classification of the tremor type: resting vs action vs postural vs intention, frequency, amplitude, distribution
• Basic laboratory: full blood count, TSH/fT3/fT4 (the thyroid!), blood glucose, HbA1c, liver and kidney values, electrolytes, vitamin B12
• Extended laboratory if suspected: caeruloplasmin and copper in the 24h urine (Wilson's disease in young patients!), catecholamines in the urine (phaeochromocytoma), toxicology
• Imaging: with suspected structural causes a cranial MRI, with suspected Parkinson's a DAT-SPECT if needed (depiction of the dopaminergic nerve endings in the striatum)
• Tremor analysis: accelerometry and electromyography for the quantitative recording of frequency and pattern — above all with atypical courses

More: Preparing for a doctor's appointment, Understanding blood values.

12. Therapy: what really helps

The therapy depends on the underlying condition — there is no single tremor therapy. The most important strategies:

Essential tremor

First-line therapy: propranolol (a beta blocker) and primidone (an anticonvulsant) — both reduce the tremor markedly in about half of cases. Second line: topiramate, gabapentin, benzodiazepines (cautiously because of dependence). In severe treatment-resistant cases, deep brain stimulation (DBS) of the nucleus ventralis intermedius is used — very effective but an operative procedure. A newer option is focused ultrasound therapy (MR-FUS) — non-invasive, through the intact skull.

Parkinson's disease

Levodopa is the most effective substance but not always the first choice because of late complications (fluctuations in effect, dyskinesias). Dopamine agonists (pramipexole, ropinirole, rotigotine), MAO-B inhibitors (rasagiline, selegiline) and COMT inhibitors (entacapone) are established alternatives or combination partners. Anticholinergics such as biperiden act particularly on the tremor but are to be used cautiously in older people because of cognitive side effects. In the advanced stage, DBS, an apomorphine pump or a Duodopa pump come into question.

Thyroid-related tremor

Therapy of the overactive thyroid — antithyroid drugs (carbimazole, thiamazole), radioiodine therapy or surgery if needed. The tremor usually fully recedes with the normalisation of the thyroid values.

Medication-related tremor

Where possible, reduce, replace or stop the triggering medication — always medically supervised. With non-replaceable medications (e.g. antidepressants, asthma inhalers), an accompanying beta blocker can ease the tremor.

13. Medications that trigger trembling

A large number of medications can cause tremor as a side effect — usually as an intensified action or postural tremor:

• Beta-sympathomimetics (salbutamol, formoterol for asthma/COPD) — a typical, often dose-dependent side effect
• Antidepressants — SSRIs (sertraline, citalopram), SNRIs (venlafaxine, duloxetine), tricyclic antidepressants
• Lithium for the treatment of bipolar disorder — tremor is one of the most common side effects
• Valproate and other anticonvulsants
• Levothyroxine in overdose — with further hyperthyroidism symptoms
• Antipsychotics and antiemetics (metoclopramide, domperidone) — can trigger a medication-induced parkinsonism
• Theophylline for asthma
• Stimulants (methylphenidate, amphetamines for ADHD)
• Steroids in high doses
• Caffeine and nicotine — an intensified tremor even in 'normal' amounts
• Ciclosporin and tacrolimus — immunosuppressants after transplants

Important: do not stop suspected medications on your own — above all levothyroxine, antidepressants, lithium and antipsychotics can provoke dangerous reactions when stopped abruptly. Always consult a doctor. More: Medication interactions, Taking medications correctly.

14. What you can do yourself

• Identify triggers with a 14-day diary: time of day, triggers, stress level, meals, caffeine consumption, sleep
• Reduce caffeine and nicotine — very common, underestimated tremor intensifiers
• Stress management: progressive muscle relaxation, mindfulness techniques, regular exercise — have a dampening effect on the sympathetic system
• Enough sleep — lack of sleep intensifies almost every tremor
• Regular meals to avoid low blood sugar
• Reflect on alcohol consumption — if only alcohol improves the trembling, discuss it with a doctor instead of reaching for self-medication
• Writing aids such as ergonomic pens, tablets instead of handwriting with essential tremor
• Weighted cutlery and stable drinking cups — reduce spilling and frustration in everyday life
• Occupational therapy — very effective with everyday disturbances due to tremor
• Exercise and sport — improve stability and reduce stress-related tremor

How brite helps you with trembling

brite supports you in better understanding trembling (tremor) and keeping an overview of your medications.

• Intake reminder — take Parkinson's therapy, beta blockers, thyroid medications or antidepressants regularly: brite reminds you on time. Set up a reminder
• Interaction check — recognise tremor as a medication side effect and check combinations for free — especially with lithium, SSRIs, salbutamol. Check now
• Health timeline — document a tremor diary with frequency, triggers and accompanying symptoms over time — valuable for the neurological work-up.
• Digital medication plan — all medications clearly laid out for your GP, neurology, endocrinology and pharmacy. To the medication plan

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