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What Is The Role Of The Sympathetic Nervous System In Hypertension?
Question: how do I know if my hypertension is of the SNS type?
Brief Answer:
I would explain as follows:
Detailed Answer:
Hello!
Thank you for asking on HCM!
Regarding your concern, I would explain that sympathetic nervous system plays an interrelated in the pathophysiology of hypertension. There are several indices interfering on SNS modulation over hypertension, and it is difficult to declare for sure an unequivocal role of SNS on chronic hypertension.
When discussing about this relatively new and attractive issue, we can't avoid mentioning some theoretical and almost academical concepts about BP control mechanisms.
Nevertheless, explaining in simple and direct terms, I would mention 3 ways to evaluate an increased role of sympathetic nervous system on etiology of hypertension:
(1) Measurements of muscle sympathetic nerve activity (MSNA) as a marker of sympathetic outflow in humans.
(2) Whole body and regional norepinephrine (NE) spillover evaluation.
(3) Measurement of plasma norepinephrine.
Another interesting key for evaluation is skin sympathetic activity (which precedes MSNA rise in several stressful situations.
As you can imagine, these techniques are almost experimental, and available only in some special medical centers.
Nevertheless, there is a general concordance between the results of the above three techniques.
Mechanisms of how norepinephrine influence on BP level and also MSNA influences are modulated, seems to be very complicated for just a simplified explanation. Just to mention that MSNA correlates perfectly with total peripheral resistance (which is an important component of BP determination), and is inversely correlated with cardiac output (CO - another important component of BP) at least in young men adults.
If you have the opportunity to be involved in any similar clinical studies dealing with this issue (SNS influences on hypertension), you will have the possibility to fully elucidate your uncertainties about this matter. Otherwise if you are really interested to go to the en dof the story, you have to create any live contacts with those special laboratories and check the above mentioned indexes.
Hope to have been helpful to you!
Feel free to ask me whenever you need! Greetings! Dr. Iliri
I would explain as follows:
Detailed Answer:
Hello!
Thank you for asking on HCM!
Regarding your concern, I would explain that sympathetic nervous system plays an interrelated in the pathophysiology of hypertension. There are several indices interfering on SNS modulation over hypertension, and it is difficult to declare for sure an unequivocal role of SNS on chronic hypertension.
When discussing about this relatively new and attractive issue, we can't avoid mentioning some theoretical and almost academical concepts about BP control mechanisms.
Nevertheless, explaining in simple and direct terms, I would mention 3 ways to evaluate an increased role of sympathetic nervous system on etiology of hypertension:
(1) Measurements of muscle sympathetic nerve activity (MSNA) as a marker of sympathetic outflow in humans.
(2) Whole body and regional norepinephrine (NE) spillover evaluation.
(3) Measurement of plasma norepinephrine.
Another interesting key for evaluation is skin sympathetic activity (which precedes MSNA rise in several stressful situations.
As you can imagine, these techniques are almost experimental, and available only in some special medical centers.
Nevertheless, there is a general concordance between the results of the above three techniques.
Mechanisms of how norepinephrine influence on BP level and also MSNA influences are modulated, seems to be very complicated for just a simplified explanation. Just to mention that MSNA correlates perfectly with total peripheral resistance (which is an important component of BP determination), and is inversely correlated with cardiac output (CO - another important component of BP) at least in young men adults.
If you have the opportunity to be involved in any similar clinical studies dealing with this issue (SNS influences on hypertension), you will have the possibility to fully elucidate your uncertainties about this matter. Otherwise if you are really interested to go to the en dof the story, you have to create any live contacts with those special laboratories and check the above mentioned indexes.
Hope to have been helpful to you!
Feel free to ask me whenever you need! Greetings! Dr. Iliri
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
What really got me wondering if I may be a victim of neurogenic hypertension is the fact that my feet become nice and warm every night while sleeping and then about 1-2 hours after getting up they start to get cold! Could it be that after awaking my SNS gets too active and starts constricting my arteries? I always usually always feel somewhat nervous during the day. I read that since it is so hard to test for an overactive SNS, doctors sometimes base their diagnosis on other physical signs such as the person having sleep apnea or a fast sinus heart rate, which I have both. There is a doctor XXXXXXX J Mann who says that the best treatment for this type of hypertension is with separate beta and alpha blockers. He recommends Betaxolol and Doxazosin. My GP & I just started me on Nebivolol along with my Losartan today. I will see how that goes for awhile then down the road maybe try Dr Mann's approach. What do you think?
Thank you, XXXXXXX
Thank you, XXXXXXX
Brief Answer:
The best strategy is that one which proves practically successful.
Detailed Answer:
Hello Larry!
It is difficult to predict a SNS related hypertension just by relying on some non-specific clinical signs and symptoms.
As I explained you above SNS etiology of hypertension is somewhat a matter of controversies. only those specific test could yield a more reliable response.
Nevertheless, I would explain that your sleep apnea may trigger hypertension by its associated hypoxemia and hypercapnia (when non properly treated).
So, I would recommend you to consider a new review of your sleep apnea strategy with your attending specialist to relieve potential harmful consequences.
Dr. Mann's recommendation seem to be an option, as there are no predefined antihypertensive schemes.
Another option is to use Carvedilol (alpha and beta-blocking properties), which is an optimal substitution of Dr. Mann's combination.
Let's try first your GP strategy. The best strategy is that one, which proves practically successful.
Best regards! Dr. Iliri
The best strategy is that one which proves practically successful.
Detailed Answer:
Hello Larry!
It is difficult to predict a SNS related hypertension just by relying on some non-specific clinical signs and symptoms.
As I explained you above SNS etiology of hypertension is somewhat a matter of controversies. only those specific test could yield a more reliable response.
Nevertheless, I would explain that your sleep apnea may trigger hypertension by its associated hypoxemia and hypercapnia (when non properly treated).
So, I would recommend you to consider a new review of your sleep apnea strategy with your attending specialist to relieve potential harmful consequences.
Dr. Mann's recommendation seem to be an option, as there are no predefined antihypertensive schemes.
Another option is to use Carvedilol (alpha and beta-blocking properties), which is an optimal substitution of Dr. Mann's combination.
Let's try first your GP strategy. The best strategy is that one, which proves practically successful.
Best regards! Dr. Iliri
Note: For further follow up on related General & Family Physician Click here.
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
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