Hypertensive emergency

Today we discussed hypertensive emergencies. Some important points:

Some of the confusing terminology in this area:
"Urgency": SBP over ~180 or DBP over ~110 without end-organ damage- needs correction over days with oral agents
"Emergency": Above, but with acute end-organ damage, needing urgent lowering, usually with IV medications in a monitored setting.
"Malignant": Old term referring to HTN with encephalopathy or renal involvement
"crisis", "accelerated"- largely abandoned, and replaced with "emergency"

End organ complications and specific treatments:
1) Aorta- dissection (B-blockade, nitroprusside after B-bl. No pure vasodilators)
2) Brain- encephalopathy- sz, coma (avoid centrally acting agents); cerebral hemorrhage/infarction, raised ICP
3) Heart- MI, CHF (acute diastolic dysfunction leading to pulmonary edema)- careful with B-bl. May use nitro infusion
4) Kidney- renal failure- careful diuresis, calcium antagonists useful
5) Placenta (pre-eclampsia)- hydralazine, labetalol, delivery
6) Hemolysis (can look just like TTP with MAHA, fragments)

Emergency pts should go to ICU, and have art line. Generally, most extra-cerebral damage benefit from rapid lowering.

Aim for MAP decrease by no more than 20-25% within 2h or to DBP 100-110 over minutes to hours. Exceptions include aortic dissection, where more rapid decrease may be needed, and stoke, where less rapid lowering may be needed.

Special circumstances:
Cocaine- phentolamine or labetalol (avoid unopposed alpha-agonism)
Pheochromocytoma- phentolamine/phenoxybenzamine (as above)

Drugs for acute lowering:
Labetalol 10-20mg bolus then infusion
Hydralazine- 10-20mg bolus (causes reflex tachycardia)
Nitroglycerine 5-100mcg/min
Na nitroprusside- arterial vasodilator
Phentolamine -alpha antagonist

Available in some centres:
Enalaprilat (IV ACE-I)
Fendolapam (arterial vasodilator)

Link:
Click here for a good review on this topic from Chest