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- An acute elevation of blood pressure (BP) with evidence of rapid and progressive end-organ damage, particularly in the cardiovascular, renal, and CNS. Examples include acute renal injury, acute myocardial infarction (MI), acute stroke, acute heart failure. Severe hypertension (HTN) without evidence of end-organ damage (even in the presence of symptoms) is referred to as hypertensive urgency.
- Severe HTN or hypertensive crisis is defined as a diastolic BP of ≥120 mm Hg or systolic BP ≥180 mm Hg (1).
- System(s) affected: cardiovascular; nervous; pulmonary; renal
- Synonym(s): hypertensive crisis; severe HTN; malignant HTN; accelerated HTN
Incidence of hypertensive emergency: 1–2% of patients with HTN annually in the United States (2)
- ~1/3 of U.S. adults (>20 years) has HTN (2).
- Predominant age: elderly
Etiology and Pathophysiology
- Increased sympathetic tone leads to increased BP.
- Angiotensin II has multiple effects contributing to HTN and end-organ damage.
- Stimulates sympathetic tone, aldosterone release, and antidiuretic hormone release
- Chronic HTN induces vascular thickening and sclerosis.
- Central effects include enhanced resorption of salt and water.
- Chronic HTN shifts autoregulation of BP and cerebral blood flow.
- Renal disease
- Abrupt withdrawal from antihypertensives, especially clonidine
- Withdrawal from CNS depressants
- Medications: SSRIs, decongestants, appetite suppressants, steroids (including oral contraceptives), MAOI interaction with certain foods or drugs, drugs of abuse (cocaine, amphetamine)
- Thrombotic thrombocytopenic purpura
- Severe burns
- Postoperative HTN
- Genetics: Risk of hypertensive emergency is higher in African Americans.
- Predominant sex: male > female
- History of poorly controlled HTN
- Drug abuse
- Noncompliance with medications; abruptly stopping antihypertensive medication without supervision
Treat HTN and counsel patients on importance of compliance with antihypertensive treatment and dangers of stopping medications abruptly.
Commonly Associated Conditions
- Chronic renal failure
- Renovascular HTN
- Acute glomerulonephritis
- Renal vasculitis
Elderly patients may experience isolated systolic HTN due to decreased baroreceptor sensitivity.
- Usually associated with renal disease
- May present with abdominal pain
- Preferred agents for children include labetalol, nicardipine, and nitroprusside.
- Labetalol, nicardipine, or hydralazine is preferred. Nitroprusside decreases placental blood flow, and cyanide metabolite crosses the placenta; may result in fetal toxicity with prolonged exposure
- Treat preeclampsia.