[Pathological Study of Pure Autonomic Failure].

Area of Science:

• Neuropathology
• Autonomic Neuroscience
• Geriatric Medicine

Background:

• Pure autonomic failure (PAF) is a Lewy body disease subtype affecting the peripheral autonomic nervous system.
• Differential diagnosis includes multiple system atrophy and small fiber neuropathy (e.g., amyloidosis).
• Orthostatic hypotension without parkinsonism is a common clinical presentation.

Purpose of the Study:

• To investigate the neuropathological characteristics of Pure Autonomic Failure (PAF).
• To explore the potential early stages of PAF within a large aging autopsy cohort.
• To correlate clinical features with neuropathological findings in PAF.

Main Methods:

• Analysis of autopsy cases from the Brain Bank for Aging Research (BBAR) cohort.
• Review of clinical diagnoses, focusing on orthostatic hypotension and parkinsonism.
• Examination of neuropathological features, including Lewy body distribution and other age-related pathologies.

Main Results:

• Only two cases with clinical PAF diagnosis were identified among over 10,000 autopsies.
• These cases exhibited diffuse Lewy body pathology affecting the peripheral autonomic nervous system, brainstem, limbic system, and neocortex.
• Lewy pathology confined to the peripheral autonomic nervous system was found in 5% of cases with Lewy pathology, potentially representing early PAF.

Conclusions:

• Neuropathological findings in identified cases met criteria for dementia with Lewy bodies (DLB), suggesting dementia as a late complication.
• Lewy body pathology solely in the peripheral autonomic nervous system may indicate the earliest stage of PAF.
• Further research is needed to fully elucidate the spectrum and progression of PAF.