52 y/o female with a PMH of HTN and HLD presents with mental status change over the past 12 hours. She is non-compliant with medications and her initial BP is 252/130.
Physical exam shows pt is A&Ox1, with an otherwise normal neuro exam. Labs show some AKI on CKD, CT-Head is normal. You plan to admit the patient to medicine and the team asks you to give a fluid bolus before starting therapy. But isn’t this going to worsen the patient’s already elevated BP?
The diagnosis of hypertensive emergency is made based upon the findings of hypertension in the setting of end-organ damage (usually heart, brain, or kidneys). What you really care about is the rate of increase rather than the actual BP number (there is no defining threshold). The goal is to reduce the MAP 15-20% in the first hour using short acting titratable agents such as nicardipine or labetalol.
But why the fluids? Along with the endothelial dysfunction that comes with hypertensive emergency, the renin-angiotensin-aldosterone system is also cranked up causing a pressure natriuresis. These patients are actually volume depleted (with the exception of CKD/dialysis with anuria). When antihypertensive therapy is started, they can bottom out their BP very quickly. Additionally, fluids can improve renal perfusion and suppress renin secretion (shutting off the RAA system).