Chorea/Ballism

There are many causes of chorea, such as pregnancy (chorea gravidarum), Huntington disease, benign hereditary chorea, neuroacanthocytosis, Sydenham chorea, systemic lupus erythematosus, focal vascular lesions, medications (particularly the chronic use of neuroleptics and oral contraceptives), various metabolic and endocrine disorders (hyperthyroidism, hypoparathyroidism, or hyperparathyroidism and hypoglycemia or hyperglycemia), and others.

In adults, the most common cause of chorea is medication, especially the use of levodopa in Parkinson patients or the long-term use of neuroleptic drugs or metoclopramide, which causes tardive dyskinesia. In children, Sydenham chorea remains the most common cause.

The second most common cause of chorea in adults is Huntington disease (HD). First described by George Huntington in1872, this autosomal dominant neurodegenerative disorder, with a 100% penetrance, has an abnormal trinucleotide (CAG) gene expansion, with the defective gene located in the short arm of chromosome 4. The disorder is characterized by choreiform movements and dementia or behavioral changes. In the United States, the estimated prevalence is 5 to 10 cases per 100,000 people. Age at onset is in the fifth to sixth decades of life, with duration of illness of 15 years in the adult and 8 to 10 years with the Westphal variant. Because of its insidious onset, the onset of symptoms is often not recognized, and abnormal movements are erroneously attributed to anxiety. Patients often have personality and behavioral changes early in the disease and these may be the initial manifestation in more than 50% of cases. Eventually, symptoms become prominent and disabling. Speech becomes dysarthric. Oculomotor alterations, such as impaired saccade initiation, particularly an inability to initiate saccadic eye movement without blinking or head thrusts, are common. Loss of optokinetic nystagmus can occur after some years. The only laboratory study available to confirm the diagnosis is genetic testing. In early stages of the disease, brain magnetic resonance imaging (MRI) may show nonspecific changes in the neostriatum, caudate, and putamen; striatal atrophy, most notably the caudate head, occurs later in the disease.

Benign hereditary (familial) chorea, an autosomal dominant disorder, begins early in childhood. Mild generalized chorea, affecting the distal extremities more than the proximal muscle groups, is the characteristic movement disorder; when present, minor neuropsychiatric features, such as mildly lower scores on cognitive tests, complete the clinical picture. Benign hereditary chorea has been associated with mutations in the TITF-1 gene.

Sydenham chorea is a manifestation of acute rheumatic fever. It is also called “St. Vitus’s dance,” acute chorea, chorea minor, or rheumatic chorea. Although more common in adolescent girls, it is also seen in adults. The clinical features of chorea are similar to those described for Huntington disease. Obsessive-compulsive and impulsive disorders and emotional lability may also occur. Prophylaxis with antibiotics is recommended until adulthood for children with Sydenham chorea because rheumatic fever recurs in up to one third of patients.

Athetosis is a slow writhing movement of the fingers and toes, seen most often in patients with cerebral palsy, particularly when excited or when trying to communicate. Dystonic posturing, tremor, ataxia, or scissoring gait usually accompanies athetotic movements.

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