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submitted by strugglebus(76),

Propanolol is a non-selective Beta blocker. So your HR will decrease (B1), which will cause a compensatory increase in TPR.

home_run_ball  ^ Above is partially right: Propranolol is non-selective Beta blocker: Beta1 stimulation causes inc HR, therefore blocking it will dec HR and dec Cardiac output Beta 2 stimulation causes vasodilation, therefore blocking it will CAUSE UNOPPOSED alpha1 activation --> therefore increasing total peripheral resistance. +13  
amarousis  so why tf do we give beta blockers for hypertension -.- +3  
dr_jan_itor  I would also add that the patient was previously on an a2 inhibitor (clonidine), which he ran out of. So he is rebounding on that with upregulated a1 receptor activity. Adding labetalol would cause a greater degree of unopposed alpha, increasing tpr +1  
llamastep1  @amarousis They are used for hypertension because the hypotensive effect of the reduced CO is greater than that of the effect of the increase of TPR. Cheers. +  


submitted by meningitis(176),

When standing up, the body normally activates sympathetic system to avoid orthostatic hypotension.

But since there is now an additive effect of the pheochromocytoma adrenergics, it will lead to a hypertension

(i.e: Double vasoconstriction = Pheo adrenergics + Sympathetic system)

sympathetikey  Brilliant. +2  
medschul  Would pheo have a normal resting BP though? +  
meningitis  I was trying to justify these tricky questions but very true medschul.. It shouldn't have normal resting BP. Sometimes it seems these NBME always have a trick up their sleeve. Im getting paranoid lol +  
nala_ula  The reason why the patient probably has normal HTN is because Pheochromocytoma has symptoms that occurs in "spells" - they come and go. Apparently in that moment, when the physician is examining her, she doesn't have the HTN, but like @meningitis explained, so many adrenergic hormones around leads to double the vasoconstriction when the patient stands up. +5  
meningitis  Thank you @nala_ula for your contribution! Really filled in the gap Iwas missing. +1  
nala_ula  No problem! Thank you for all your contributions throughout this page! +1  
mjmejora  I thought the pheochromocytoma was getting squeezed during sitting and releasing the epinephrine then. kinda like how it can happen during manipulation during surgery. Got it right for sorta wrong reasons then oh well. +  
llamastep1  When she sits in the examination table there would be a normal activation of the sympathetic system from the stress of getting examined which is amplified by the pheo. Cheers. +