Pure autonomic failure

Orthostatic hypotension: Review and expert position statement

Orthostatic hypotension is defined as a drop in systolic blood pressure of at least 20mmHg or a drop in diastolic blood pressure of at least 10mmHg within 3minutes of standing. It is a common disorder, especially in high-risk populations such as elderly subjects and patients with neurological diseases, and is associated with markedly increased morbidity and mortality. Its management can be challenging, particularly in cases where supine hypertension is associated with severe orthostatic hypotension. Education of the patient, non-pharmacological measures, and drug adaptation are the cornerstones of treatment. Pharmacological treatment should be individualized according to the severity, underlying cause, 24-hour blood pressure profile, and associated coexisting conditions. First-line therapies are midodrine and fludrocortisone, which may need to be combined for optimal care of severe cases.

An overview on pure autonomic failure

Pure autonomic failure (PAF) is a neurodegenerative disease affecting the sympathetic component of the autonomic nervous system and presenting as orthostatic hypotension (OH). It is a rare, sporadic disease of adults. Although OH is the primary symptom, the autonomic dysfunction may be more generalised, leading to genitourinary and intestinal dysfunction and sweating disorders. Autonomic symptoms in PAF may be similar to those observed in other autonomic neuropathies that need to be ruled out. PAF belongs to the group of α synucleinopathies and is characterised by predominant peripheral deposition of α-synuclein in autonomic ganglia and nerves. However, in a significant number of cases, PAF may convert into another synucleinopathy with central nervous system involvement with varying prognosis: Parkinson's disease (PD), multiple system atrophy (MSA), or dementia with Lewy bodies (DLB). The clinical features, the main differential diagnoses, the risk factors for "phenoconversion" to another synucleinopathy as well as an overview of treatment will be discussed.

Pure Autonomic Failure-A Localized Alpha Synucleinopathy with a Potential for Conversion to More Extensive Alpha Synucleinopathies

Pure autonomic failure (PAF) is an alpha synucleinopathy with predominant involvement of the autonomic ganglia and peripheral nerves. The hallmark clinical feature is orthostatic hypotension. However, genitourinary, sudomotor, and cardiac involvement is also common. Many patients also develop supine hypertension. Almost a quarter of patients can phenoconvert or evolve into Parkinson's disease, multiple system atrophy, and Lewy body dementia in the future. Early severe bladder involvement, higher supine noradrenaline level, early motor involvement, and dream enactment behavior increase the risk of phenoconversion. The diagnosis is confirmed via autonomic function testing and serum noradrenaline measurement. The treatment is mainly supportive. The non-pharmacological treatment includes adequate fluid, dietary salt, compression stockings, and abdominal binders. The drug therapies to improve blood pressure include midodrine, fludrocortisone, pyridostigmine, and droxidopa. The diagnostic criteria need to be updated to incorporate the recent understandings. The treatment of orthostatic hypotension and supine hypertension is mainly based on case series and anecdotal reports. Randomized control trials are needed to ascertain the best treatment strategies for PAF.