Hypertension in Polycythemia Rubra Vera

Hypertension in Polycythemia Rubra Vera

Multiple mechanisms have been proposed as the cause of systemic hypertension in polycythemia rubra vera:

1. Increased number of circulating erythrocytes increase the blood viscosity and clog the renal circulation causing renal ischemia, which triggers the secretion of renin. Renin in turn increases the secretion of angiotensin, a potent vasoconstrictor which increases blood pressure. Angiotensin increases secretion of aldosterone which causes salt and water retention, another reason for increased blood pressure
2. Hypertension could be due to scavenging of nitric oxide by free hemoglobin. Nitric oxide being a potential vasodilator, reduction in available nitric oxide in the vessel walls could lead on to vasoconstriction and accelerated hypertension [1].

A rare clinical syndrome of refractory secondary hypertension, renal artery stenosis and erythrocytosis has been reported by Bhadauria D and associates [2]. The patient had primary erythrocytosis as an expression of polycythemia rubra vera.

References

1. Rusak T, Misztal T, Piszcz J, Tomasiak M. Nitric oxide scavenging by cell-free hemoglobin may be a primary factor determining hypertension in polycythemic patients. Free Radic Res. 2014 Feb;48(2):230-8.
2. Bhadauria D, Sharma RK, Kaul A, Prasad N, Gupta A, Gurjar D, Jain A. A rare clinical syndrome of refractory secondary hypertension, renal artery stenosis and erythrocytosis. NDT Plus. 2011 Jun;4(3):175-7.