Orthostatic hypotension. I. Functional and neurogenic causes

Area of Science:

• Neurology
• Cardiovascular Physiology

Background:

• Adequate upright blood pressure (BP) relies on baroreceptor reflexes and blood volume.
• Functional BP disruptions are common and reversible, but permanent neurologic disorders can impair orthostatic BP control.

Purpose of the Study:

• To review neurologic disorders affecting orthostatic BP control.
• To differentiate mechanisms of autonomic dysfunction in various hypotension conditions.

Main Methods:

• Literature review of neurologic disorders impacting BP regulation.
• Analysis of autonomic nervous system dysfunction in orthostatic hypotension.

Main Results:

• Multiple system atrophy involves diffuse neurologic and autonomic dysfunction, causing failed peripheral vasoconstriction.
• Idiopathic orthostatic hypotension features selective autonomic nerve disorder with impaired norepinephrine release.
• Sympathicotonic orthostatic hypotension involves excessive sympathetic discharge, with unclear pathogenesis.
• Peripheral neuropathies, common in diabetes mellitus, can also impair sympathetic vasoconstriction.

Conclusions:

• Neurologic disorders significantly impact orthostatic BP maintenance through various autonomic pathways.
• Understanding these mechanisms is crucial for diagnosing and managing hypotension in neurological conditions.