Hypertensive Emergencies
Basics
Basics
Basics
Description
Description
- Hypertensive crisis:
- Severely elevated BP defined by a SBP >179 mm Hg or a DBP >109 mm Hg
- Hypertensive urgency:
- Severely elevated BP without end-organ damage
- Hypertensive emergency:
- Severely elevated BP associated with acute end-organ damage
- Loss of autoregulation of blood flow in hypertensive emergency:
- Arterioles vasoconstrict to counter pressure
- High pressures overwhelm arterioles and endothelial damage occurs
- Endothelial injury leads to increase permeability, activation of the coagulation cascade and platelets, and deposition of fibrin
- Activation of the renin–angiotensin system and the sympathetic nervous system:
- Leads to further vasoconstriction and production of proinflammatory cytokines
- End-organ ischemia:
- Renewed release of vasoconstrictors
- Worsened by pressure natriuresis
- Triggers a vicious cycle
- Organs affected:
- Brain (encephalopathy, CVA, ICH)
- Retina (hemorrhage, papilledema)
- Heart (MI, aortic dissection, acute HF)
- Kidneys (acute renal failure)
- Placenta (preeclampsia/eclampsia)
Etiology
Etiology
- Essential HTN
- Renal:
- Vascular disease
- Parenchymal disease
- Coarctation of the aorta
- CNS disorders:
- Head trauma
- CVA/ICH
- Brain tumor
- Spinal cord injury
- Endocrine:
- Pheochromocytoma
- Cushing syndrome
- Primary hyperaldosteronism
- Renin-secreting tumor
- Drugs:
- Cocaine, phencyclidine, amphetamines
- Erythropoietin, tacrolimus, cyclosporine, corticosteroids, oral contraceptives
- MAOI interactions
- Antihypertensive medication withdrawal
- Lead intoxication
- Autonomic hyperreactivity:
- Guillain–Barré syndrome
- Acute intermittent porphyria
- Postop pain and/or anesthesia complications
- Pregnancy related:
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