Clinical Reasoning: A 54-Year-Old Woman With Progressive Headache and Neurologic Decline

A 54-year-old woman presented with headache and vasculopathy. She was treated for reversible cerebral vasoconstriction syndrome but continued to have clinicoradiographic decline with headache, seizures, systemic symptoms, and progression of vasculopathy on imaging. We present the diagnosis of a rare genetic disease with its various neurologic complications and systemic manifestations. Our case also illustrates the importance of differences in the metabolism of various antiseizure medications, recognition of which may avoid precipitating the disease.