The relative change in blood pressure from baseline is more important than it's absolute value.
Treatment will vary widely, depending on the specific context.aortic dissection, sympathetic crashing acute pulmonary edema, cocaine intoxication). In most cases, the primary process will be more obvious clinically, dominating the initial clinical presentation (e.g. Secondary hypertension is used here to refer to hypertension which is a result of some other primary process.When vasoconstriction is treated, this may unmask underlying volume depletion – which is best treated with IV crystalloid administration. (#2) Patients are sometimes intravascularly volume depleted (due to sodium excretion in the kidney that is triggered by the hypertension).Alternatively, use of a beta-blocker will not address this underlying problem. Thus, the optimal treatment may include a vasodilator (most often a calcium channel blocker). (#1) The primary pathophysiological problem is excessive vasoconstriction.Clinical implications of this pathophysiology include the following:.RAS activation, in turn, causes vasoconstriction – which leads to worsening hypertension.
The core of this spiral is that hypertension causes microcirculatory damage that impairs renal perfusion, leading to activation of the renin-angiotensin system (RAS). Malignant hypertension is the “purest” form of primary hypertensive emergency.Nonetheless, as a general concept this remains useful. The term “malignant hypertension” is somewhat outdated (classically this was defined based on the presence of extreme hypertension and hypertensive retinopathy – which was often lethal before the advent of antihypertensives).This leads to a vicious spiral that, if untreated, will progress to death. When chronic hypertension is not treated, it may eventually reach a tipping point where the hypertension itself is causing progressive microvascular damage.Pathophysiology of malignant hypertension Trying to titrate an antihypertensive infusion against systolic and diastolic blood pressure simultaneously is often impossible and confusing (for example, what happens if the systolic target is reached but not the diastolic?).The best way to titrate antihypertensive drugs in a logical fashion is to target a specific MAP. The dosing of any antihypertensive drug can be titrated only against a single variable.Reason #3: MAP is preferred in guiding therapy MAP is probably the single parameter most closely related to the risk of hypertensive emergency.However, the risk of hypertensive emergency seems overall be more closely related to the diastolic pressure than the systolic pressure. We tend to focus on the systolic blood pressure (“she had a systolic of 250!!”).Reason #2: MAP may be most closely related to the risk of hypertensive emergency This could make the MAP the most accurate measurement.Automated oscillometric Bp cuffs measure the MAP directly (whereas the systolic and diastolic Bp are estimated using proprietary algorithms).There are several reasons that MAP is the preferred measurement of blood pressure, as follows: reason #1: MAP is what the automated Bp cuff is actually measuring The MAP is the average arterial pressure, which can be estimated as follows: (5) Transition to oral antihypertensives.īefore getting started, it will be useful to define our preferred measurement of blood pressure: the mean arterial pressure (MAP).(4) Control Bp with IV antihypertensive agents.(3) Re-evaluation for an underlying cause of the HTN.(2) Is this actually a hypertensive emergency?.Pathophysiology of malignant hypertension.
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