[A case of Takayasu arteritis diagnosed following posterior reversible encephalopathy syndrome].

A 53-year-old woman presented with chronic anorexia and gait disturbance. During evaluation at another hospital, brain MRI revealed abnormal high signal intensities in both supratentorial and infratentorial regions, prompting referral and admission to our hospital. On admission, she exhibited non-lateralized hypertension, decreased responsiveness, hypophonia, masked face, bradykinesia, shuffling gait, and hyperreflexia. Blood tests showed mild inflammatory markers. Based on her hypertension and MRI findings, posterior reversible encephalopathy syndrome (PRES) was diagnosed, and antihypertensive therapy was initiated. Her symptoms and imaging findings improved, though some abnormalities persisted. During further evaluation for the cause of hypertension, she contracted COVID-19. Despite recovery, low-grade fever and inflammatory response persisted. Contrast-enhanced CT revealed perivascular enhancement around the aortic arch branches, leading to a diagnosis of Takayasu arteritis. This case highlights PRES as a clinical trigger for the diagnosis of Takayasu arteritis.