michigan hypertension core curriculum - State of Michigan

lability. The wide fluctuations in BP have been linked to a large catecholamine surge. In rare instances,
vagal predominance (labeled “vagotonia” ) may occur, characterized by hypotension, bradycardia and
in severe cases asystole. In 1985 Fagius and Walsh performed temporary anesthetic blocks of CN IX
and X in human subjects they reported severe hypertension, tachycardia with increased sympathetic
activity. As mentioned previously BD mimics pheochromocytoma and this must be ruled out in this
setting. 4-7
TREATMENT
In keeping with its under-recognized and under-reported nature, the literature addressing
treatment of BD is sparse, consisting mostly of observational case reports. In the acute setting,
hypertensive crisis has been managed by IV labetalol, nitroprusside or phentolamine. In less acute
settings centrally acting α adrenoreceptor blockade with clonidine or phenoxybenzamine has been
advocated. 6,7
CONCLUSION
The baroreceptor reflex is vital in ameliorating acute changes in blood pressure. BD results in
unexplained labile hypertension, tachycardia, and palpitations that can mimic pheochromocytoma. This
syndrome is under-recognized and under-reported, with limited data looking at long term sequelae. 5-7
References:
1. Thrasher TN. Baroreceptors, baroreceptor unloading, and the long-term control of blood
pressure. Am J Physiol Regul Integr Comp Physiol 2005;288:R819-27.
2. Timmers HJ, Wieling W, Karemaker JM, Lenders JW. Baroreflex failure: a neglected type of
secondary hypertension. Neth J Med 2004;62:151-5.
3. Sharabi Y, Dendi R, Holmes C, Goldstein DS. Baroreflex failure as a late sequela of neck
irradiation. Hypertension 2003;42:110-6.
4. Zar T, Peixoto AJ. Paroxysmal hypertension due to baroreflex failure. Kidney Int 2008;74:126-
31.
5. De Toma G, Nicolanti V, Plocco M, et al. Baroreflex failure syndrome after bilateral excision of
carotid body tumors: an underestimated problem. J Vasc Surg 2000;31:806-10.
6. Ketch T, Biaggioni I, Robertson R, Robertson D. Four faces of baroreflex failure: hypertensive
crisis, volatile hypertension, orthostatic tachycardia, and malignant vagotonia. Circulation
2002;105:2518-23.
7. Heusser K, Tank J, Luft FC, Jordan J. Baroreflex failure. Hypertension 2005;45:834-9.
NKFM & MDCH 225