Hypertensive Urgency and Emergency

My last post was on defining hypertension and secondary causes of hypertension. Continuing with the theme, I wanted to refresh myself on this common inpatient problem.

Definitions

• Hypertensive Emergency - Severe hypertension in adults (systolic blood pressure ≥180 mmHg and/or diastolic blood pressure ≥120 mmHg) associated with symptoms that signal end-organ damage (hypertensive encephalopathy, subarachnoid or intracerebral hemorrhage, retinal hemmorrhage, kidney injury, acute pulmonary edema, aortic dissection, and rebound after withdrawal of antihypertensive medications).
• Hypertensive Urgency - Severe hypertension in adults (systolic blood pressure ≥180 mmHg and/or diastolic blood pressure ≥120 mmHg) associated with none or mild symptoms, often a mild headache, but no signs of acute end-organ damage.

Etiology - often occurs in patients who have been non adherent with either their antihypertensive drug regimen or their low-sodium diet. Severe hypertension can also develop in patients who are adherent to their medications and following ingestion of large quantities of salt and can be controlled by resuming a low-salt diet.

Treatment

Hypertensive Urgency - The blood pressure should be reduced over a period of hours to days. The blood pressure should usually be lowered to <160/<100 mmHg. However, the mean arterial pressure should not be lowered by more than 25 to 30 percent over this relatively short period of time. This means that patient's who have very elevated blood pressures, the goal may be a little higher than 160/100. The choice of therapy depends on the timeline. If the blood pressure needs to be lowered over a period of hours (Patients judged to be at high risk for imminent cardiovascular events due to severe hypertension, including those with known aortic or intracranial aneurysms), UptoDate recommends oral furosemide, oral clonidine, or oral captopril. If the blood pressure needs to be lowered over a period of days, resumption of antihypertensive therapy, initiation of antihypertensive therapy, or the addition of another antihypertensive drug is adequate.

Hypertensive Emergency - Nitroprusside dilates both arterioles and veins and is generally considered to be the most effective parenteral drug for most hypertensive emergencies. Nitroprusside acts in less than one minute and its effects disappear within 1 to 10 minutes, thereby minimizing the risk of hypotension. Nitroprusside's major limitation is its metabolism to cyanide which could lead to the development of cyanide or rarely thiocyanate toxicity. Nitroglycerine, CCB, Labetalol (a combined beta-adrenergic and alpha-adrenergic blocker with a rapid onset of action, 5 min, makes it useful in the treatment of hypertensive emergencies), Esmolol, Hydralazine and Phentolamine (good in catecholamine excess). On my ward rotations, the most common drugs I see used in Hypertensive Emergencies are Nitro drips and Labetolol.