- Primary: Isolated movement disorders, i.e. without cognitive decline, epilepsy or other neurological features; not progressive and inherited, so check family history.
- Secondary: An identifiable secondary cause such as brain injury, infection, toxic or drug exposure; may improve with removal of provoking cause.
- Heredodegenerative: As part of a generalised degenerative process; additional psychiatric and systemic problems.
- Psychogenic: History of psychological disturbance and medically unexplained symptoms.
Tremor
Tremor is easily recognised as a rhythmic sinusoidal movement. When describing tremor it is useful to detail whether present with rest (in Parkinson’s disease), posture (e.g. holding the arms outstretched in front of the patient, as in the so-called essential tremor) and with action (e.g. drinking from a cup). Important causes of postural tremor include physiological tremor, anxiety, hyperthyroidism, certain medications, alcohol and caffeine use, essential (familial) tremor and Wilson’s disease.
Isolated kinetic (action) tremors can be seen with structural abnormalities of the brainstem and cerebellar connections, as in multiple sclerosis, vascular disease or secondary tumours.
Essential (Familial) Tremor
Definition
Essential tremor (ET) is a syndromic diagnosis. It typically presents as a symmetrical postural tremor and often has an autosomal dominant fashion of inheritance.
Epidemiology
Bimodal onset (childhood and late life onset), men and women are equally affected. Prevalence is approximately 300 per 100 000.
Aetiology
A family history is found in approximately 50% of cases (autosomal dominant inheritance).
History
Typically a fine distal symmetrical upper limb tremor, starting gradually and worsening over time. Voice tremor may be present. Often marked improvement with alcohol is seen.
Investigations
There are no diagnostic tests. Important to exclude hyperthyroidism or drugs causing tremor.
Management
Medical: First line therapy—propranolol or primidone or a combination of both; second line therapy—gabapentin or topiramate. Surgical: Severe functionally impairing ET resistant to medical therapies may be suitable for and respond to deep brain stimulation surgery.
Chorea
Definition
Described as brief irregular purposeless movements flowing from one body part to another. People appear restless or fidgety. Chorea is often generalised but may be confined to one side of the body (hemichorea) typically due to a structural cause within the contralateral basal ganglia.
Aetiology
- Genetic: Huntington’s disease (autosomal dominant), Wilson’s disease (autosomal recessive) and other inherited causes.
- Autoimmune: Systemic lupus erythematosus, antiphospholipid syndrome and Sydenham’s chorea.
- Infections, medications (L-Dopa-induced dyskinesias) and metabolic (thyroid dysfunction and chorea gravidarum).
Huntington’s Disease (HD)
Definition
An autosomal dominant degenerative disease characterised by progressive behavioural disturbance, dementia and chorea.
Epidemiology
HD affects 4–8/100 000; males and females are affected equally.
History
Motor onset is variable but usually in the fourth decade; psychiatric symptoms, particularly disinhibited behaviour, may be the first feature. Abnormalities of eye movement, gait, upper motor neurone signs and tics may be seen along with chorea.
Investigations
Genetic testing (HD is a triplet repeat disorder with mutation in the Huntingtin gene on chromosome 4). MRI may show caudate nucleus atrophy.
Management
Medical (tetrabenazine may be used to improve chorea) and multi-disciplinary team approach (psychiatry, genetic counselling for family members, physiotherapy and occupational therapy).
Wilson’s Disease
Definition
Wilson’s disease is a condition characterised by a defect in copper metabolism leading to accumulation of copper in liver and basal ganglia.
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