Pure autonomic failure (PAF), or Bradbury-Eggleston syndrome, is a degenerative disorder of the autonomic nervous system presenting in middle to late life, affecting men more often than women. The disorder appears to be confined to the sympathetic and parasympathetic nervous systems. The adrenal medulla is relatively spared.
The pathology of PAF has not been completely elucidated, but there is known to be a loss of cells in the intermediolateral column of the spinal cord and a loss of catecholamine uptake and catecholamine fluorescence in sympathetic postganglionic neurons. Autonomic failure should be distinguished from two other disorders classified as primary autonomic failure: Multiple System Atrophy (MSA) and idiopathic Parkinsons Disease (PD). PAF is less progressive and generally induces less disabling symptoms than do these other syndromes.
In PAF, there should be no indication from the history or physical examination of cerebellar, striatal, pyramidal, and extrapyramidal dysfunction. Hoarseness and sleep apnea are two unusual symptoms highly suggestive of Multiple System Atrophy. Alpha-synuclein accumulates in cytoplasmic inclusions in affected brain areas in patients with MSA and PD. Alpha-synuclein accumulation in cytoplasmic inclusions in brainstem nuclei and in pre- and postganglionic sympathetic and parasympathetic nerves was recently demonstrated in a case of PAF. The role of alpha-synuclein accumulation in neuronal death has yet to be determined.
How is PAF Diagnosed?
The definitive diagnosis of hypotension as the cause of orthostatic symptoms is usually made by the demonstration of a decline in systolic blood pressure of 20 mm Hg and diastolic blood pressure of 10 mm Hg after at least one minute of standing. However, a decrease in systolic blood pressure by 50 mm Hg or greater is not unusual in these patients. This hypotension may be so severe that seizures supervene in perhaps 3% of affected patients. A diagnosis of PAF cannot be excluded on the basis of a single measurement of upright blood pressure that does not meet the above criteria. Several measurements of orthostatic blood pressure should be made. About 5% of PAF patients have angina pectoris, usually in the absence of significant angiographically demonstrable coronary atherosclerosis. PAF patients tolerate high altitude very poorly, perhaps because they hyperventilate in this situation.
PAF is considered a generally mild condition. Treatments for PAF focus on managing symptoms
- Medication options focus on raising blood pressure (fludrocortisone, midodrine, somatostatin, erythropoietin, and other vasopressor agents)
- Non-drug treatment options include squatting, abdomincal compression, bending forward and using compression stockings.
- To maintain upright position, some patients find that crossing their legs helps.
- Drinking water may help to temporarily raise blood pressure. Sixteen ounces of water can raise blood pressure as much as 40 mm Hg, with a peak at 30 minutes after ingestion.
- An important aspect of treatment centers on patient education.