This 75-year-old woman reported gait instability and involuntary movements for about 18 months preceding her evaluation. She also felt “wobbled” when walking, had difficulty negotiating stairs and curbs, and started to fall in any direction within 6 months, prompting the need for a walker. Her family noted “wiggling of her fingers” and “wrinkling” of her forehead as early as 3 months after the onset of gait problems. Although she was initially unaware, the abnormal movements progressed dramatically over 6 months to involve her face, trunk, and limbs. She was also noted to have word-finding difficulties, poor concentration, and decreased attention, interspersed with angry outbursts and generalized apathy. Of note, she had accumulated a 50-pack per year smoking history. She had no family history of similar neurological problems.

Our patient presented with progressive ataxia; axial-predominant chorea (face > head > trunk and limbs); cognitive impairment (Montreal Cognitive Assessment, 22/30); stocking-glove hypesthesia to temperature, vibration, and position; and patellar hyperreflexia and jaw jerk. The differential diagnosis for a subactute, progressive, late-onset chorea and ataxia with neuropsychiatric features includes metabolic, hereditary, autoimmune, and paraneoplastic disorders (Table 118.1). A brain MRI demonstrated no cerebellar atrophy but abnormal T2-weighted and FLAIR hyperintensity in the putamen and periventricular region (Fig. 118.1). Additional investigations showed normal blood count, creatine kinase, liver profile, serum and urine copper, ceruloplasmin, antinuclear antibody (ANA), double-stranded DNA (dsDNA), rheumatoid factor (RF), thyroid-stimulating hormone (TSH)/T3/T4, and antiphospholipid antibody panel, except for an “inconclusive” immunoglobulin G (IgG) anticardiolipin (17, normal less than 15). There were no acanthocytes on blood smear, and her lipoprotein electrophoresis was normal. Genetic testing was negative for Huntington disease (HD) and dentatorubral-pallidoluysian atrophy (DRPLA). Symptomatic treatment with amantadine yielded minimal improvement, but tetrabenazine, titrated to a dose of 25 mg three times a day, led to marked improvement of her chorea, although with mild parkinsonian features as a drug-related complication.