Chorea and basal ganglia hypermetabolism as indicators of APS and probable-APS

Objectives: Chorea is a rare manifestation of Antiphospholipid Antibody Syndrome (APS). It has been hypothesized a direct non-thrombotic interaction of APL antibodies with neurons of the dopaminergic nigro-striatal pathway. This interaction could determine membrane depolarization that would result in chorea as clinical manifestation. Several clinical manifestations of the APS have been excluded from the diagnostic criteria of the syndrome, including neurological. These manifestations have been included in a separate category viz “Probable APS” since they could predate the development of actual thrombosis. Long-term therapy of these patients with either antiaggregant or anticoagulant might have to be considered. Materials: A 77-year-old-woman was admitted for subacute onset of choreiform movements affecting the limbs of the left side of the body, associated with a mild slowdown of ideomotor processes and impairment of speech. Her medical history revealed one miscarriage at the fourth month and a full-term pregnancy. Methods: In the hypothesis of APS, lab analyses revealed high titres of aCL, abeta2GPI and LAC antibodies, the absence of complement consumption and prolonged aPTT combined with in-range platelets level. Brain MRI showed a mild chronic vasculopathy. 18F-FDG PET scan showed a hyper-metabolism of the basal ganglia. Results: Based on the high aPL titre, FDG-PET hyper-metabolism of the basal ganglia and lack of MR-ischemic findings suggestive for thrombosis, a diagnosis of Probable-APS was made. A symptomatic treatment with haloperidol was started, determining complete remission of the motor symptoms, that persisted at a 12-week follow-up evaluation. In parallel a preventive treatment with aspirin was started, in absence of further thrombotic complications. Discussion: Movements disorders associated with hypermetabolism of the basal ganglia can be features of APS and Probable-APS. We hypothesize a role of 18F-FDG PET in the diagnostic process to assess basal ganglia hypermetabolism, since brain MRI alone would prove inconclusive or negative. In absence of a medical history characterized by thrombotic events, such assessment would support a Probable-APS diagnosis, thus allowing to start an appropriate preventive treatment (with either antiaggregant or anticoagulant) anticipating thrombotic complications, such as cerebral infarction, as a consequence of the transition to overt APS. Conclusions: This case report outlines the importance of aPL titres assessment in patients with choreiform disorders and the role of 18F-FDG PET in the diagnostic process, since even in absence of a thrombotic medical history, such assessment would support a Probable-APS diagnosis, thus allowing to start an appropriate preventive treatment (with either antiaggregant or anticoagulant).