(a) Etiology Comments Tardive dyskinesia Common, especially secondary to antipsychotic medicines Sydenham chorea Post-streptococcal; in 20% cases of rheumatic fever; children Systemic lupus Chorea in 1-7% erythematosus Neurosyphilis Usually concomitant HIV infection Hyperthyroidism Chorea in 2% of cases; usually young-middle age adults Drug-induced chorea Lithium, antiepileptic agents, stimulants, L-dopa, estrogen Pregnancy Rare; increased risk with history of Sydenham chorea Polycythemia vera Chorea in 0.5-5% of cases
Senile chorea Late onset; may be clinically indistinguishable from late-onset HD Basal ganglia lesions Strokes, infections, tumors (a) Note that genetic factors are important in many of these conditions, although none is strictly a Mendelian disorder.