Remote Adolescent-Onset Chorea Preceding Thrombotic Antiphospholipid Syndrome: A Case Report.

Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by vascular thrombosis and/or obstetric morbidity in the presence of persistent antiphospholipid antibodies. Chorea is an uncommon neurological manifestation, reported in approximately 1% of patients, and is not included among the clinical domains required for classification. We report the case of a 28-year-old woman who presented with acute left-sided sensorimotor deficits. Her only relevant history was an episode of chorea involving the left upper limb at 18 years of age, which resolved spontaneously after an incomplete etiological workup at another institution. Neuroimaging demonstrated a right frontal ischemic lesion, and cardioembolic and large-vessel causes were excluded. Prompted by the prior history of chorea, testing revealed persistently high-titer anticardiolipin IgG and anti-β2-glycoprotein I IgG antibodies, establishing a diagnosis of primary APS. She was started on warfarin and achieved functional independence without recurrent vascular events. This case illustrates that juvenile-onset chorea may represent the heralding manifestation of APS, preceding the qualifying thrombotic event by a decade. An isolated, self-limited chorea of undetermined cause should prompt antiphospholipid antibody testing, as early recognition may allow timely thromboprophylaxis and potentially prevent cerebrovascular events in young patients.