Subarachnoid Hemorrhage in Autoimmune Vasculitis: A Rare Presentation of Systemic Lupus Erythematosus-Antineutrophil Cytoplasmic Autoantibody-Associated Vasculitis Overlap Syndrome.

Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) and systemic lupus erythematosus (SLE), though they share similar clinical characteristics, are distinguishable based on specific characteristics. The concomitant presentation of SLE and AAV as overlap syndrome is rare and makes the diagnosis challenging. Here, we describe a rare case of SLE and AAV overlaps presenting with hemorrhagic stroke as initial presentation, which has been reported only once before. The presence of several positive autoantibodies made the diagnosis challenging, but a kidney biopsy provided the definitive diagnosis and aided in initiating immunosuppressive therapy. The patient did not respond to standard initial surgical measures to lower elevated intracranial pressure and showed significant improvement to immunosuppressive therapy proving the temporal relationship. The authors of this case study aim to highlight the importance of considering SLE-AAV overlap in patients presenting with features similar to those described in the case report and intervening early, as delays in diagnosis can be fatal.