Antiphospholipid‐Related Chorea: Two Case Reports and Role of Metabolic Imaging

BACKGROUND: Antiphospholipid syndrome (APS) is a complex acquired autoimmune disease with a wide clinical spectrum. Chorea is a rare neurological manifestation of APS. CASES: We report two elderly patients with APS‐related chorea in whom functional imaging (18F‐FDG positron emission tomography, FDG‐PET) supported the diagnosis and compare our findings with existing literature. LITERATURE REVIEW: Among 142 clinical cases of antiphospholipid‐related chorea found in literature, only 10 had undergone brain metabolic imaging. Striatal hypermetabolism was evident in all cases (6) that underwent FDG‐PET cerebral imaging. Cerebral perfusion single photon emission computed tomography (SPECT) was normal in two cases, while the other two presented with basal ganglia hypoperfusion. CONCLUSIONS: Brain FDG‐PET usually shows striatal hypometabolism in neurodegenerative types of chorea as opposed to striatal hypermetabolism observed in most cases of chorea from reversible etiologies, such as APS‐related chorea. When a patient's clinical presentation is not clearly suggestive of either a neurodegenerative or autoimmune chorea, and first‐line investigations are normal, FDG‐PET may help in the differential diagnosis, especially in the presence of striatal hypermetabolism. SPECT data are less numerous and show either normal scans or basal ganglia hypoperfusion.