Sydenham Chorea: Putaminal Enlargement.

Background: Our aim in this study was to evaluate the efficacy of magnetic resonance imaging (MRI) studies in the detection of brain regions effected by Sydenham chorea and to determine whether they provided data regarding the pathogenesis of Sydenham chorea. To this end, we assessed basal ganglia structures in Sydenham chorea patients and control group by quantitative MRI volumetric analysis.

Methods: Patients with a recent onset of chorea and control subjects matched for age and gender were included in the study. Medical history, laboratory tests, and physical and neurologic examinations were reviewed. All MRIs were considered within normal limits. High-resolution T1-weighted 3D magnetization-prepared rapid acquisition of gradient echo scans were used for quantitative volumetric assessment of the brain via the "volBrain" method.

Results: Twenty-four subjects with Sydenham chorea (16 girls and 8 boys, aged between 7 and 16 years) and 35 control subjects were evaluated. Mean age was 11.25 ± 2.89 years for Sydenham chorea patients and 10.58 ± 2.53 years for the controls. No significant difference was found relative to globus pallidus, caudate, and thalamic volumes between patients with Sydenham chorea and controls. The relative mean total, left, and right putamen volumes were significantly larger in patients with Sydenham chorea compared to controls ( = .003, = .018, = .001, respectively).

Conclusion: Selective neuroanatomic differences in putamen among other basal ganglia structures and significant increases in size are consistent with a hypothesis of a cross-reactive antibody-mediated inflammation of the putamen as being the pathophysiologic mechanism for this disorder.