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ValtteriKaasinen

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]