Neurology Resident & Fellow Section A 72-year-old woman with hyperkinetic movements Teaching NeuroImages Neurology Resident & Fellow Section © 2018 American Academy of Neurology

Vignette A 72-year-old female developed progressive choreic movements involving predominantly right upper and lower limbs and slightly the orofacial muscles. No other abnormalities, such as ataxia were present. Brain MRI, blood glucose level, thyroid function and rheumatologic panel were unremarkable. Genetic testing for Huntington’s disease, and C9orf72 expansions were negative. Rossi M et al. © 2018 American Academy of Neurology

Video Rossi M et al. VIDEO LEGEND Patient shows predominately right hemichorea and subtle involvement of orofacial muscles due to polycythemia vera that resolve completely after treatment with phlebotomy and hydroxyurea. Rossi M et al. © 2018 American Academy of Neurology

Chorea due to polycythemia vera Basal hematocrit and hemoglobin levels were normal, but increased to abnormal values (56% and 18.5 g/dL) after one year of chorea onset. The JAK2V617F mutation was positive. Chorea disappeared with phlebotomy and hydroxyurea. Neurologists should suspect this rare treatable entity in elderly patients with chorea or hemichorea even with initially normal hematocrit levels. The pathophysiology underlying polycythemia vera-associated chorea remains unclear, as the main proposed model of basal ganglia hypoperfusion due to venous stasis caused by hyperviscosity1 was not subsequently confirmed.2 REFERENCES. Bruyn GW, Padberg G. Chorea and polycythaemia. Eur Neurol 1984;23:26-33. 2. Kim W, Kim JS, Lee KS, Kim YI, Park CW, Chung YA. No evidence of perfusion abnormalities in the basal ganglia of a patient with generalized chorea-ballism and polycythaemia vera: analysis using subtraction SPECT co-registered to MRI. Neurol Sci 2008;29:351-354. Rossi M et al. © 2018 American Academy of Neurology