Steroid-responsive encephalopathy subsequently associated with Alzheimer's disease pathology: A case series

Background: Steroid-responsive encephalopathies can be considered vasculitic or non-vasculitic. Clinicopathological studies of non-vasculitic steroid-responsive encephalopathy are unusual, but can explain the range of diagnoses consistent with a steroid-responsive presentation in life. Objective: To extend the range of clinical features and pathological findings consistent with steroid-responsive encephalopathy. Design, methods, and patients: A clinicopathological case series of four patients (two women, ages 54–71 years) with steroid-responsive encephalopathy followed at this institution until the time of death. Results: Clinical features were suggestive of Creutzfeld–Jakob disease (CJD), dementia with Lewy bodies (DLB), and parkinsonism, but pathological examination revealed only Alzheimer's disease-related findings without evidence of Lewy bodies or prion disease in all cases. All patients demonstrated marked, sustained improvement following steroid treatment, based on clinical, magnetic resonance imaging, and/or electroencephalogram studies. Alzheimer's disease was not diagnosed in life due to the atypical clinical features, lack of hippocampal atrophy on brain imaging, and a dramatic symptomatic response to steroids. Conclusions: Steroid-responsive encephalopathy is the clinical presentation of some patients with Alzheimer's disease-related pathology at autopsy, and can be consistent with the clinical diagnoses of parkinsonism, DLB, or CJD disease in life.