Aseptic Meningitis Following Rozanolixizumab in a Patient With Refractory Anti-MuSK Positive Myasthenia Gravis: A Case Report.

Rozanolixizumab is a neonatal Fc receptor (FcRn) blocker recently approved for treating generalized myasthenia gravis (gMG), particularly in patients who are anti-AChR or anti-MuSK antibody positive. Although clinical trials have demonstrated a favorable safety profile, rare adverse neurological effects remain underreported. A 36-year-old woman with refractory anti-MuSK-positive generalized myasthenia gravis received an infusion of rozanolixizumab after failing to respond to corticosteroids and azathioprine. 5 days post-infusion, she presented with an acute-onset headache, nausea, vomiting, photophobia, phonophobia, and neck stiffness. Cerebrospinal fluid (CSF) analysis revealed a white blood cell count of 150 cells/μL with 90% neutrophils, normal protein, and glucose levels. The infectious meningitis and encephalitis panel was negative. She was managed supportively, and her symptoms resolved over the following week without antimicrobial therapy. This case suggests a possible link between Rozanolixizumab and aseptic meningitis. Clinicians should be aware of this potential adverse effect and consider drug-induced etiologies in similar clinical scenarios. Early recognition may prevent unnecessary treatment and hospitalizations.