2) Orthostatic Hypotension
5-29 % of all causes syncope
Aging changes in physiology that
predispose to orthostatic hypotension:
- decrease in B-adrenergic
responsivenss
- decrease in baroreflex:
(which should increase heart rate and
vasoconstrict)
| Definition: | A decline in systolic BP > 20 mm Hg with supine to standing &/or increase in heart rate > 20 beats/min. | ||||||||||||||||
| Technique: | measure BP & pulse: -lying for > 5 minutes then sitting, then, standing for 1 and 3 minutes | ||||||||||||||||
| Causes : | a)
Volume loss b) Medications c) Situational d) Primary Autonomic Disease e) Secondary Autonomic Disease f) Adrenal Insufficiency |
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a)
Volume Loss
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b)
Medications;
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| c) Situational (many of these involve Vasovagal mechanisms also)
*"36 % elderly NH pop. had orthostatic hypotension postprandially BUT: only 2 % had symptoms from it. d) Primary Autonomic Disease
e) Secondary Autonomic disease
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1)
Neuropathic
2)Central Nervous System disease (CNS)
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DIAGNOSIS: of Orthostatic Hypotension
The "Gold Standard" for diagnosis
Proven orthostatic hypotension (OH) (see definition above) and symptoms reproduced
via: 1) clinically demonstrated (OH) with symptoms
or
2) Tilt table testing* with provocation of symptoms
The "Fall-Back Position" for diagnosis
Proven orthostatic hypotension and strong suspicions
based on consistent history
* Tilt table testing usual techinigue:
1st Passive testing:
Technique; fasting, serial BP’s in various tilt
positions up to 60 degrees with patient standing still
2nd Isoproteronol infusion:
Technique: as above plus infusion of
isoproteronol
Positive: demonstrates drop in BP> 20
mm Hg and symptom reproduction