Chorea is a nonrhythmic, jerky, rapid, nonsuppressible involuntary movement, mostly of the distal muscles and face; movements may be incorporated into semipurposeful acts that mask the involuntary movements. Athetosis (slow chorea) is nonrhythmic, slow, writhing, sinuous movements predominantly in distal muscles, often alternating with postures of the proximal limbs. Hemiballismus is unilateral rapid, nonrhythmic, nonsuppressible, wildly flinging movement of the proximal arm and/or leg; rarely, such movement occurs bilaterally (ballismus). Hemiballismus is a severe form of chorea.

Chorea and athetosis are defined by clinical manifestations; many experts believe that when they occur together (as choreoathetosis), athetosis is a dystonia superimposed on chorea. Chorea and athetosis result from impaired inhibition of thalamocortical neurons by the basal ganglia. Excess dopaminergic activity may be the mechanism.

Huntington disease (see Movement and Cerebellar Disorders: Huntington Disease) is the most common degenerative disorder causing chorea. Other causes include hyperthyroidism, hypoparathyroidism, use of oral contraceptives, pregnancy, SLE that affects the CNS, drugs (eg, levodopa, phenytoinSome Trade Names
DILANTIN
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, cocaine), tardive dyskinesia (due to use of typical and most atypical antipsychotics), autoimmune disorders, and paraneoplastic syndromes. Sydenham chorea (see Rheumatic Fever: CNS) can occur in rheumatic fever and may be the first symptom of it. A tumor or an infarct in the striatum (caudate or putamen) can cause acute unilateral chorea (hemichorea).

Senile chorea is a type of chorea that occurs in patients > 60; it tends to affect oral and perioral muscles. Senile chorea is diagnosed when

• Chorea occurs as an isolated symptom in patients > 60.
• No other cause is identified.
• The chorea is not progressive.
• Dementia is not present.

In many cases of apparent senile chorea, a specialized evaluation identifies a symptomatic cause of chorea (eg, toxic, metabolic, autoimmune); in all patients, symptomatic causes should be ruled out.

Clinicians should seek and treat the cause of chorea whenever possible. Sydenham chorea and chorea due to infarcts of the caudate nucleus often lessen over time without treatment. Chorea due to hyperthyroidism usually lessens when thyroid function is normalized. In Huntington disease, drugs that suppress dopaminergic activity, such as antipsychotics (eg, risperidoneSome Trade Names
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), and dopamine-depleting drugs (eg, reserpineSome Trade Names
SERPASIL
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, tetrabenazine) can be used. However, improvement may be limited and transient. These drugs may be judiciously used to treat choreas without a definable cause.

Chorea gravidarum occurs during pregnancy, often in patients who have had rheumatic fever. Chorea usually begins during the 1st trimester and resolves spontaneously at or after delivery. If treatment before delivery is necessary because chorea is severe, barbiturates are indicated because they have fewer fetal risks than other drugs used to manage choreas. Rarely, a similar disorder occurs in women taking oral contraceptives.

Hemiballismus is caused by a lesion, usually an infarct, in or around the contralateral subthalamic nucleus. Although disabling, hemiballismus is usually self-limited, lasting 6 to 8 wk. If severe, it can be treated with an antipsychotic for 1 to 2 mo.

Last full review/revision January 2013 by Hector A. Gonzalez-Usigli, MD; Alberto Espay

Content last modified January 2013