Orthostatic Hypotension

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A sustained fall in blood pressure that exceeds 20mmHg systolic or 10mmHg diastolic within 3 minutes of a stand test or upright tilt to >60 degrees.

True orthostatic hypotension is a sign of autonomic dysfunction and dysautonomia in adults and in children. It may also occur with reductions of blood or plasma volume, as an effect of medications

Non-neurogenic OH are caused by Drugs, hypovolemia pheochromocytoma, Addison Disease, and other ilnesses that critically reduce central blood volume (e.g. severe gastroenteritis and dehydration)
Neurogenic OH is identified with Autonomic vasoconstrictor failure due to inadequate release of norepinephrine from sympathetic vasomotor neurons.



The figure (from Pharmacotherapy of autonomic failure. Shibao C., Okamoto L., Biaggioni I. Pharmacol Ther. 2011 Jun 8 
Shows several well-known diseases causing neurogenic orthostatic hypotension. 
Genetic (Dopamine beta-hydroxylase  deficiency) , autoimmune ganglionopathy occur and secondary  causes such as diabetes, and amyloidosis are the most common causes of NOH. 


while blood pressure typically falls inexorably Hr does not usually increase in compensatory fashion. thus vagal-parasympathetic deficits are also usually present. 



Orthostatic Stress  Testing & instrumentation
Circulatory Measurements
Circulatory Autonomic Testing
Initial Orthostatic Hypotension
Research Studies
Fainting and Related Phenomena a Lay Review
Orthostatic Intolerance
Orthostatic Hypotension