michigan hypertension core curriculum - State of Michigan

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The baroreceptor reflex plays an important role in buffering acute changes in BP, whereas
longer long term control is maintained through neurohumoral mechanisms. It is important to note that
the baroreceptor set point is not fixed; for instance in hypotension the set point will be lowered, in some
instances the BRs response can be silent. The contrary is true of established hypertension, where
the baroreflex is set at a higher threshold and a reduced gain. The reduction in gain is thought to be a
consequence of reduced BRs sensitivity. This finding is also noted in congestive cardiac failure. 1-3
BARORECEPTOR DYSFUNCTION (BD)
There have been many animal studies, namely in dogs, where temporary denervation of
baroreceptors resulted in severe volatile BP readings. BD is a syndrome. Most case reports describing
BD are in the setting of carotid endartectomies and carotid artery anomalies, although it can arise
through any disruption in the baroreceptor pathway (e.g., neck trauma or irradiation, carotid tumor
resection, lesions in the nucleus tractus solitarii, CN IX and X). 3,4,5 It can masquerade clinically as
a pheochromocytoma because of its associated volatile hypertension (often exceeding SBP≥ 200),
possible stigmata of hypertensive emergency, orthostatic tachycardia, palpitations and emotional
224 Hypertension Core Curriculum