PRES in the Setting of Mycophenolate Use for Lupus Nephritis: A Diagnostic Challenge With Therapeutic Implications

Posterior reversible encephalopathy syndrome (PRES) is a rare condition causing posterior brain edema, seizures, visual changes, and altered mental status. It is associated with autoimmune disease, immunosuppressants, eclampsia, renal disease, and malignancy. PRES may cause injury through either hypertension-induced hyperperfusion, causing edema, or endothelial dysfunction due to inflammation or cytotoxic injury. Prompt recognition, blood pressure control, and addressing triggers typically lead to full recovery.Here we discuss the case of a 27-year-old woman who initially presented with debilitating arthralgia and a vasculitic rash on both lower extremities. She was hospitalized while an autoimmune workup was conducted. The investigation revealed autoimmune disease, and outpatient rheumatology later confirmed systemic lupus erythematosus complicated by class IV lupus nephritis. She was initiated on therapy with mycophenolate, however, within one week she returned to the hospital with seizures and marked hypertension. MRI findings and clinical features were consistent with PRES. Given the close timing with therapy initiation, mycophenolate was suspected as the cause. With withdrawal of immunotherapy and strict blood pressure control, she improved significantly. Follow-up imaging at 3 months demonstrated almost complete resolution of PRES.This case aims to elucidate a potential novel cause of PRES associated with mycophenolate use. We propose that mycophenolate may dysregulate vascular adhesion molecules, impairing endothelial response to hypertension-induced damage. Our goal is to raise awareness and guide clinicians managing patients on mycophenolate.