Chorea is a movement disorder (dystonia). It comes from the Greek word 'choreia' - dancing. It describes involuntary, irregular, random and flowing movements which flit from one part of the body to another. The movements may be simple or elaborate, and can be incorporated into purposeful movements.¹

Other terms which may be classified under 'chorea' (or as separate dystonias) are:

• Athetosis: slow, irregular, sinuous writhing movements, often of the fingers. If this occurs with chorea, it is called choreoathetosis.
• Ballism and hemiballismus: Large-amplitude, proximal, flinging movements (hemiballismus if unilateral).

These movements can overlap and co-exist.¹

Causes of chorea^1,2,3

May be primary (inherited or idiopathic) or secondary (to infection, immune disorders, metabolic disease, drugs. etc.). The underlying pathology is not fully understood, but may involve an imbalance between pathways in the basal ganglia.

• Inherited:
  • Huntington's disease.
  • Benign hereditary chorea (an autosomal dominant condition with choreiform movements, distinct from Huntington's disease, with onset in early childhood.⁴).
  • Wilson's disease.
  • Neuroacanthocytosis (a rare, multisystem, degenerative disorder - usual age of onset is approximately 30 years).
  • Dentatorubral-pallidoluysian atrophy.
  • Other rare, inherited neurological conditions which include chorea.
• Acquired:
  • Drugs and toxins - various (see box, below).
  • Immune mediated:
    • Sydenham's chorea (St Vitus' dance - the most common; may be post-streptococcal infection).
    • Other immune-mediated choreas: can occur in: systemic lupus erythematosus (SLE), antiphospholipid antibody syndrome and vasculitis, e.g. polyarteritis nodosa, Behçet's disease, multiple sclerosis, CNS angiitis.
  • Infectious chorea:
    • Can occur with meningitis, (including aseptic meningitis), tuberculous meningitis, encephalitis including herpes simplex encephalitis,⁵ Lyme disease, HIV-AIDs (due to toxoplasmosis abscess or direct HIV invasion of basal ganglia), new variant Creutzfeldt-Jakob disease and subacute bacterial endocarditis. One case report describes chorea following Legionnaire's disease.⁶
  • Vascular chorea:
    • Stroke (chorea is a rare complication of stroke).
    • Polycythaemia (unknown mechanism).
    • Moyamoya disease (an intracranial vasculopathy).⁷
  • Hormonal disorders:
    • Hyperthyroidism.
    • Hypoparathyroidism with hypocalcaemia.
    • Pregnancy (chorea gravidarum), oral contraceptives and hormone replacement therapy⁸ (rare; may have a history of Sydenham's chorea).
  • Metabolic:
    • Electrolyte and biochemical disturbance, e.g. hypernatraemia and hyponatraemia, hyperglycaemia and hypoglycaemia, hypomagnesaemia, hypocalcaemia, hepatic and renal failure.
    • Vitamin deficiency: B1 and B12.
    • Has also been reported with a ketogenic diet in a child.
  • Paraneoplastic syndromes, e.g. small cell carcinoma of the lung, renal cell carcinoma, ovarian cancer and lymphoma.
  • Postoperative - following childhood cardiac surgery ('post-pump choreoathetosis').
  • Other CNS conditions:
    • Trauma, including cerebral palsy.
    • Intracranial tumours.
    • Senile chorea.
    • Ventriculoperitoneal shunts.³

Presentation^1,4

The choreiform movements are visible as brief, irregular, jerky and purposeless involuntary movements of the distal extremities and face. They are asymmetrical and present at rest. Movements are neither repetitive nor rhythmic, but appear to flit randomly from one part of the body to another.

Involvement of the face may lead to grimacing, tongue movements or grunting noises.

The movements may vary in severity: in a mild form, they may appear as restlessness or fidgeting movements of the hands; there may be mild intermittent exaggeration of gesture and expression. More severe forms may show an unstable, dance-like gait or a continuous flow of disabling, violent movements.

Chorea often occurs with athetosis, which adds twisting and writhing movements.

Other signs:

• Motor 'impersistence' (cannot maintain a sustained posture).
• Variable force of grip; with alternate squeeze and release ('milkmaid's grip'); may drop objects involuntarily.
• On attempting tongue protrusion, the tongue often pops in and out ('harlequin's tongue'). Patients may mask the chorea by voluntarily augmenting the choreiform movements with semi-purposeful movements.
• Chorea is often worsened by anxiety and subsides during sleep - although the movements may persist during sleep.

Assessment¹

Assessment for a possible cause includes:

• Time course of symptoms (acute/gradual onset), progression, medical history and medication.
• Systems and neurological examination, including:
  • Signs of infectious disease.
  • Focal neurological signs.
  • Mental state: Huntington's disease.
  • Face and eyes: exophthalmos (thyrotoxicosis), Kayser-Fleischer rings (Wilson's disease), conjunctival injection (polycythaemia).
  • Skin: SLE.
  • Heart: rheumatic fever.

Investigation¹

Investigations depend on the presentation of the individual patient, and include:

• FBC.
• Biochemistry: electrolytes, including calcium and magnesium; renal function; liver function.
• Thyroid function.
• Consider also:
  • Tests for syphilis, HIV, tuberculosis, toxoplasmosis, Lyme disease.
  • Antistreptolysin O titre: for suspected streptococcal infection.
  • ESR, CRP and autoantibodies: for suspected autoimmune aetiology.
  • Copper studies (for Wilson's disease, if under the age of 40 or with a family history of liver disease or neuropsychiatric disease).
  • MRI scanning: for intracranial structural lesion.
  • EEG: if seizures rather than movement disorder are considered.

Differential diagnosis

• When mild, chorea can be difficult to differentiate from restlessness.¹
• May need to be differentiated from seizures.
• Choreiform movements may be difficult to distinguish from slower, writhing athetosis movements. Choreoathetosis describes both.
• Myoclonus is much more rapid and does not flow from one muscle to another.

Management^1,3

Drug treatment

Drugs which may be used to alleviate symptoms include:

• Dopaminergic antagonists (e.g. neuroleptics) - these can be effective, but use is curtailed by side-effects, in particular, tardive dyskinesia and Parkinsonism.
• Dopamine-depleting drugs, e.g tetrabenazine; may be combined with the dopamine antagonist pimozide.
• GABAergic drugs, e.g. clonazepam, gabapentin, and valproate, are possible adjunctive therapy.
• Benzodiazepines such as clonazepam and diazepam - but side-effects, e.g. sedation, are a concern. They may be useful in the first few days until there is a response to other drugs.⁴
• Chorea following cardiac transplantation has been reported to respond to steroid treatment.

Other treatments

• For secondary chorea, treat the underlying cause, if feasible.
• Vitamin E may hasten resolution of tardive dyskinesia.¹
• Deep brain stimulation is an emerging technique that may benefit some patients.

Complications³

• Chorea may be a disabling symptom, leading to bruises, falls and injuries.
• May cause difficulty with meals.
• May cause social difficulty with appearance.

Prognosis

The prognosis depends on the underlying disease.

• With secondary causes, the chorea may resolve on treatment of the underlying condition, although the course of recovery can be prolonged in some cases⁸.
• In tardive dyskinesia, on stopping the causative medication, resolution of chorea can be very slow and is not certain.¹
• Chorea following acute stroke often remits spontaneously.²

Document references

1. Bhidayasiri R, Truong DD; Chorea and related disorders. Postgrad Med J. 2004 Sep;80(947):527-34. [abstract]
2. Cardoso F; Chorea: non-genetic causes. Curr Opin Neurol. 2004 Aug;17(4):433-6. [abstract]
3. Vertrees SM et al; Chorea in Adults, Medscape, May 2009
4. Robertson WC; Chorea in Children, Medscape, Aug 2010
5. Kullnat MW, Morse RP; Choreoathetosis after herpes simplex encephalitis with basal ganglia involvement Pediatrics. 2008 Apr;121(4):e1003-7. Epub 2008 Mar 31. [abstract]
6. Bamford JM, Hakin RN; Chorea after legionnaire's disease. Br Med J (Clin Res Ed). 1982 Apr 24;284(6324):1232-3.
7. Baik JS, Lee MS; Movement disorders associated with moyamoya disease: a report of 4 new cases and Mov Disord. 2010 Jul 30;25(10):1482-6. [abstract]
8. Steiger MJ, Quinn NP; Hormone replacement therapy induced chorea. BMJ. 1991 Mar 30;302(6779):762.
9. Quinn AG, Ellis WR, Burn D, et al; Chorea precipitated by sulphasalazine. BMJ. 1991 Apr 27;302(6783):1025.
10. Mulder LJ, van der Mast RC, Meerwaldt JD; Generalised chorea due to digoxin toxicity. Br Med J (Clin Res Ed). 1988 Apr 30;296(6631):1262.

Internet and further reading

• Videos of movement disorders, Oxford University Press (USA). Accessed March 2009
• Higgins DS Jr; Chorea and its disorders. Neurol Clin. 2001 Aug;19(3):707-22, vii. [abstract]
• Cardoso F; Huntington disease and other choreas. Neurol Clin. 2009 Aug;27(3):719-36, vi. [abstract]
• Kinirons M, Ellis H; French's Index of Differential Diagnosis; 14th Edition, 2005

Acknowledgements