Abstract
We present the case of a 70-year-old woman with progressive weakness and altered sensation in her hands and feet, complicated by intermittent confusion, status epilepticus, and posterior reversible encephalopathy syndrome (PRES). She was known to have cervical spinal stenosis and gave a vague history of an autoimmune disorder, which was in remission for the past many years. Extensive evaluation for infectious, compressive, and paraneoplastic causes was unrevealing. Investigations revealed severe axonal peripheral neuropathy with active vasculitic features confirmed on nerve biopsy, which were not picked up by the PET scan. With aggressive blood pressure control and high-dose corticosteroids, PRES resolved radiologically, and neurological function improved gradually. This case highlights the diagnostic complexity of systemic vasculitis presenting with simultaneous central and peripheral nervous system involvement, underscores the indispensable role of biopsy when non-invasive tests are inconclusive, and illustrates how timely immunosuppression and hemodynamic control can reverse central manifestations while stabilizing peripheral nerve injury.