This is a UKMLA-centred history guide about abnormal involuntary movements.
Contents
Introduction
Abnormal involuntary movement disorders, also called ‘dyskinesias’, can be categorised as hyperkinetic or hypokinetic, although there is often an overlap. Parkinsonism is the main type of hypokinetic disorder, while hyperkinetic disorders include tremor, dystonia, chorea, tics and myoclonus. Causes of dyskinesia can be categorised into primary (e.g. basal ganglia pathologies) or secondary (e.g. antipsychotics, hyperthyroidism, anxiety). It is important to gather collateral information from relatives or video evidence, as this can provide a better understanding of the problem and lead to appropriate management.
Presenting Complaint
1. Tremor
Rhythmical oscillation due to alternating agonist-antagonist muscle contraction.
Features of common tremors:
2. Chorea
Means “dance”. These are abrupt, brief, irregular and involuntary movements. The person appears to be fidgety and clumsy. Often seen in Huntington’s disease or as a complication of levodopa treatment in Parkinson’s disease.
- A variant of chorea is ballism (or ballismus), which is a violent, flinging movement of the limbs. It is most commonly caused by a stroke.
3. Athetosis
Slow, writhing, “worm-like” movement of the limbs, often presenting with chorea, which is termed choreoathetosis. Causes include cerebral palsy and Huntington’s disease.
4. Tics
Sudden, repetitive, non-rhythmic movements or sounds which are briefly suppressible. Vocal phenomena include echolalia (repeating others’ phrases), palalia (repeating one’s own phrases), and coprolalia (swearing). It is commonly associated with Tourette syndrome.
5. Myoclonus
Shock-like muscle jerks. Causes include epilepsy and hypnic jerks.
6. Dystonia
Sustained muscle contractions causing abnormal posture, often with non-rhythmic, repetitive movements, e.g. cervical dystonia. Initiated or worsened by voluntary action, which can be task-specific, e.g. when writing or playing an instrument.
7. Tardive Dyskinesia
Involuntary movement of the face and jaw, typically caused by antipsychotics.
Site/Location
Tremor
- Unilateral → idiopathic Parkinson’s disease
- Bilateral → essential tremor, drug-induced Parkinsonism
- Variable → functional, e.g. depression
Myoclonus
- Bilateral → epilepsy or brain injury
- Unilateral → hypnic jerks, muscle strain
Face and jaw → Tardive dyskinesia, dystonia
Chorea → Presents bilaterally
Onset
Tremor
- <30 years → physiological, hyperthyroidism, or functional
- >40 years → essential tremor, early onset Parkinson’s disease
- >60 years → idiopathic Parkinson’s disease, stroke
Myoclonus
- 10-20 years → juvenile myoclonic epilepsy
Chorea
- 20-50 years → Huntington’s disease, Wilson’s disease
- <10 years → cerebral birth injury
- Any age → cerebral trauma
Tics
<20 years → Tourette syndrome
Characteristics and Associated Features
Tremor
- Low frequency (3-6 Hz), bradykinesia, rigidity → Parkinsonism
- High frequency (8-10 Hz) → essential tremor, hyperthyroidism, physiological
- Coarse → lithium toxicity
- Fine → hyperthyroidism, physiological, chronic lithium use
- Intentional → cerebellar disease
- Postural → physiological
Chorea and …
- Athetosis → Huntington’s disease (more common), cerebral palsy
- Kayser Fleischer rings → Wilson’s disease
- Scissoring gait, learning disabilities → Cerebral palsy
- Ballism → subthalamic nucleus stroke
- Tardive dyskinesia → antipsychotic use, long-term levodopa use
Myoclonus and …
- Other seizures e.g. atonic, tonic-clonic → Epilepsy
Vocal tics e.g. coprolalia (swearing) → Tourette syndrome
Timing
Sudden onset:
- Cerebral trauma, birth injury
- Ischaemic or haemorrhagic stroke
- Medications e.g. antipsychotics, antiepileptics, levodopa
- Metabolic e.g. hypoglycaemia, electrolyte imbalances
Gradual and progressive:
- Neurodegeneration e.g. idiopathic Parkinson’s disease, Huntington’s disease
- Malignancy e.g. growing tumour
Gradual but non-progressive:
- Metabolic e.g. thyroid, parathyroid disorders, electrolyte imbalances
- Autoimmune e.g. systemic lupus erythematosus, antiphospholipid syndrome, post-streptococcal (Syndenham’s chorea)
Precipitating Factors
Tremor
- Worse on movement → essential tremor
- Worse at rest → Parkinsonism
Myoclonus
- Only in early morning or late evening → juvenile myoclonic epilepsy
- Only during sleep → hypnic jerks
Red Flags
- Loss of consciousness, tongue biting → epilepsy
- Bladder or bowel dysfunction → late-stage Parkinson’s disease or Parkinson-plus syndromes
- Progressive neurological deficits → neurodegeneration, growing cerebral tumour
- Acute, focal neurological deficits → stroke
- Nocturnal headache, headache worse on lying down -> space-occupying lesion
Past Medical History
- Throat infections → post-streptococcal (Syndenham’s chorea)
- History of attention deficit hyperactivity disorder, obsessive compulsive disorder → Tourette syndrome
- Depression, schizophrenia → functional/psychiatric tremors/antipsychotic use
- Antipsychotic drugs → Parkinsonism, tardive dyskinesia, chorea
- Tremor and …
- Asthma → salbutamol overuse (causes palpitations as well)
- Bipolar disorder→ lithium toxicity or side effects of lithium
- Schizophrenia → side effects of antipsychotics
Social History
- Recreational drug use e.g nitrous oxide → subacute combined degeneration of spinal cord
- IV drug use → discitis, epidural or brain abscess
- Alcohol misuse → alcohol neuropathy, B12 deficiency
- Significant history of smoking tobacco → Lambert-Eaton syndrome
Family History
- Chorea → Huntington’s disease
- Tremor → essential tremor
Common Differentials in OSCE’s
Examination
Inspection
- Assess the surrounding, e.g. wheelchair (for cerebral palsy), medication.
- Consider age and assess for abnormal movements at rest.
- Localise the abnormal movement. For example, dystonia in the face and neck; essential tremor in bilateral upper limb.
Palpation
- Assess tone, power and reflexes to distinguish if the cause is neurological, physiological or functional. Presence of any deficits suggests a neurological cause.
- Consider the differential stated above depending on the signs elicited.
- Assess sensory modalities e.g. pin-prick, crude touch, vibration and proprioception.
- A sensorimotor deficit suggests multiple nerves are affected, e.g. radiculopathies, peripheral neuropathies, mononeuritis multiplex, multiple sclerosis, etc.
Author – Karthikeyan Sivaganesh
Editor – Dr James Mackintosh
