A 30-year-old woman with SLE has been on hydroxychloroquine for 3 years. She develops new-onset seizures and psychosis despite normal anti-dsDNA and complement. MRI brain shows areas of cortical and white matter signal change. The MOST likely diagnosis and the specific antibody to test is:
- A Neuropsychiatric SLE (NPSLE) attributable to antiphospholipid syndrome; test antiphospholipid antibodies (anticardiolipin IgG/IgM, anti-β2-glycoprotein I, lupus anticoagulant) ✓
- B Lupus cerebritis with anti-dsDNA
- C CNS vasculitis due to ANCA
- D Anti-NMDAR encephalitis unrelated to SLE
Explanation
Neuropsychiatric SLE (NPSLE) encompasses a spectrum of central and peripheral neurological manifestations. When MRI shows thromboembolic white matter changes and the clinical picture includes seizures and psychosis in an SLE patient with normal complement/anti-dsDNA, antiphospholipid syndrome (APS) should be strongly suspected as a cause of NPSLE (thrombotic mechanism). Testing for antiphospholipid antibodies (anticardiolipin IgG/IgM, anti-β2GP1 IgG/IgM, and lupus anticoagulant on two occasions 12 weeks apart) is essential. APS-associated NPSLE is managed with anticoagulation rather than intensified immunosuppression.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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