Background: Chorea is a movement disorder in which involuntary movements occur. It can be associated to autoimmune diseases such as systemic lupus erythematosus (SLE), having been shown to be related to positive antiphospholipid antibodies. However, its exact pathophysiology is unknown. Microthrombosis of the basal ganglia, autoimmune injury of the basal ganglia or even lesion of the basal ganglia neurons have been proposed as hypotheses to explain SLE-related chorea. It is important to understand its pathogenesis so that the best treatment options can be identified.Case Presentation Summary: A 12-year-old female adolescent presented in the emergency room due to progressive worsening of choreoathetoid movements of the trunk and four limbs, slurred speech, hypophonia, and orofacial dyskinesia with 2 weeks of evolution. Brain magnetic resonance imaging (MRI) revealed bilateral frontal and parietal infracentimetric focal subcortical lesions, suggesting recent ischemia (Figures 1a and 1b). Treatment with acetylsalicylic acid (ASA) was started, and she was transferred to a tertiary hospital, where she also started tetrabenazine. Chorea improved, but brain MRI revealed a new focal lesion in the right parietal cortex (Figure 1c). Basal ganglia lesions were not found. Transcranial Doppler ultrasound revealed a microembolic sign between the left middle cerebral and anterior cerebral arteries. Thus, ASA was replaced by enoxaparin.Antinuclear antibodies (ANA) were positive in a titer of 1:160, with lupus anticoagulant antibody also being positive. Additionally, the patient revealed a prothrombin G20210A gene mutation in heterozygosity. Treatment with five-day methyl-prednisolone pulses 1g/day was initiated and continued with prednisolone 60mg/day. Intravenous immunoglobulin was performed, and hydroxychloroquine was started. Microscopic hematuria and non-nephrotic proteinuria were identified, with progressive increase, so a kidney biopsy was performed, with class V lupus nephritis being diagnosed. Treatment with mycophenolate mofetil and enalapril was then initiated. Choreoathetoid movements resolved on the 40th day of illness. Although the lupus anticoagulant antibody remained persistently positive at follow-up, the patient is free of neurologic symptoms.Learning Points Discussion: Contrary to some previous reports, thrombosis of the basal ganglia vessels does not seem to be the most likely mechanism of the SLE-related chorea.Figure 1. Initial MRI: a) Axial fluid-attenuated inversion recovery (FLAIR) sequence with fat suppression and b) diffusion-weighted imaging (DWI); 24th day MRI: c) Axial diffusion-weighted imaging (DWI). Subcortical lesions in both frontal lobes at admission, suggesting recent ischemia (images a and b), and reevaluation on the 24th day of illness with a new lesion at the high convexity of the right parietal cortex (image c).
