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Tremor
Essentials
- The most important diseases with tremor are essential tremor Essential Tremor and Parkinson's disease Parkinson's Disease.
- Various types of tremor are differentiated by clinical examination. Characterising the type of tremor makes differential diagnosis easier.
- Resting tremor and action tremor are the two main types.
- Physiologic tremor occurs in all people, e.g. as static tremor.
Tremor at rest
- Occurs in the absence of voluntary movement.
- Exhibits low frequency and wide amplitude.
- "Pill-rolling" tremor subtype is characterised by minute rolling movements of thumb and forefinger against each other with concomitant small supination-pronation movements of the forearm.
- Lower jaw and lips may tremble, but the head hardly ever.
- Tremor diminishes or disappears for a moment during movement, e.g. when the arm is lifted to vertical position, but is intensified by mental stress and anxiety.
- Tremor at rest or other tremor types do not occur during sleep.
Aetiology
- The most common cause is Parkinson's diseaseParkinson's Disease.
- Other causes
- Use of neuroleptics or other dopamine antagonists such as metoclopramide (drug-induced parkinsonism)
- Certain extrapyramidal disorders that resemble Parkinson's disease (known as "Parkinson plus" diseases or atypical parkinsonisms)
- Essential tremor Essential Tremor may also be associated with tremor at rest although action/postural tremor is clearly more intense.
Action tremor
- Manifests only when the muscles are voluntarily contracted, either in active movement or when a fixed position is maintained (static tremor), and disappears when the muscles are relaxed.
- Occurs in fingers and upper limbs, but also in head, oral region, larynx (voice) and in lower limbs.
- The amplitude of the tremor increases in accurate performance and during stress or anxiety.
- Ataxia is an important differential diagnostic sign.
- Common causes
- Essential tremor Essential Tremor
- Intensified physiological tremor
- Also in Parkinson's disease the patient may have action tremor in addition to resting tremor.
- Uncommon causes
- Cerebellar lesions
- Symptomatic tremor
- Toxic tremor
- Functional (psychogenic) tremor
Physiologic tremor
- Aetiology
- Increased secretion of catecholamines; stress, exercise, fatigue, abstinence
- Caffeine, nicotine
- Hypoglycaemia, hypothermia
- Drugs: lithium, valproic acid, antipsychotic drugs, pindolol, cimetidine, sympathomimetic drugs (isoprenaline, salbutamol, theophylline, etc.), tricyclic antidepressants, SSRIs, mexiletine, cyclosporin, thyroxine
- Can be treated with a non-selective beta-blocker (propranolol).
Metabolic tremor
- Aetiology
- Liver failure, uraemia, Cushing's disease
- Hypokalaemia, hypomagnesaemia
- Polycythaemia
- Hyperthyroidism, pheochromocytoma
- Malabsorption, vitamin B12 deficiency
- Tremor is often mainly distal and usually irrelevant when the underlying disease is considered.
Tremor caused by cerebellar disorders
- See Ataxia.
- Aetiology
- Alcoholism
- Multiple sclerosis
- Brain tumours and infarctions
- Hereditary
- In addition to static or action tremor there may be intention tremor, ataxia, disturbances of equilibrium, nystagmus, speech disturbances and muscular hypotonia.
- Tremor is accentuated in distal parts of the body, in upper limbs the frequency is faster than in lower limbs.
Toxic tremor
- Especially in heavy metal poisonings tremor in sustained position or action tremor is evident (e.g. mercury, lead, arsenic and phosphorus, but also certain chemicals, such as dioxine).
- Carbon monoxide, carbon disulphide, methanol and cyanide poisonings
- Myoclonic jerks and other involuntary movements may occur in addition to tremor, and tremor may be present also in rest.
Symptomatic tremor
- In many neurological disorders, action tremor may be present in addition to the symptoms of the underlying disease.
- Dystonias
- Certain neuropathies (e.g. hereditary), polyradiculitis
- Brain injuries
- Tourette's syndrome
- Wilson's and Huntington's disease
- Red nucleus tremor (rubral or midbrain tremor)
Orthostatic tremor
- Appears in the lower extremities when standing still.
- Moving relieves the tremor.
Task-specific tremor
- Appears only when performing some specific task, most commonly when writing with a pen.
- May be difficult to differentiate from dystonia.
Functional tremor
- Often of mixed type (both resting and action tremor) with variable frequency and amplitude
- May start suddenly and cease when no attention is paid.
References
- Bötzel K, Tronnier V, Gasser T. The differential diagnosis and treatment of tremor. Dtsch Arztebl Int 2014;111(13):225-35; quiz 236. [PubMed]
- Fasano A, Deuschl G. Therapeutic advances in tremor. Mov Disord 2015;30(11):1557-65. [PubMed]
- Bhatia KP, Bain P, Bajaj N et al. Consensus Statement on the classification of tremors. from the task force on tremor of the International Parkinson and Movement Disorder Society. Mov Disord 2018;33(1):75-87. [PubMed]