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Hypertensive Emergencies, Emergency Medicine

Basics

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

• 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-Barr � syndrome
  • Acute intermittent porphyria
• Postop pain and/or anesthesia complications
• Pregnancy related:
  • Preeclampsia/eclampsia

Diagnosis

Signs and Symptoms

History

• Inquire about:
  • Use of any prescribed and OTC medication
  • Duration and control of pre-existing HTN
    • Prior end-organ damage
  • Details of antihypertensive therapy
  • Comorbid conditions (obesity, CAD, DM)
  • Recreational drug use
• Assess for end-organ compromise in decreasing order of frequency:
  • Dyspnea
  • Chest pain
  • Headache
  • Altered mental status/confusion
  • Focal neurologic symptoms

Physical Exam

• BP measured in both arms
  • Use proper cuff size
• Assess for end-organ compromise:
  • Neurologic:
    • Level of consciousness
    • Visual fields
    • Focal motor/sensory deficits
  • Ophthalmologic:
    • Funduscopic exam (retinal hemorrhages, papilledema)
  • Cardiovascular:
    • Elevated JVP
    • Lung crackles
    • Aortic insufficiency murmur
    • S3
    • Asymmetrical pulses

Essential Workup

• 12-lead EKG:
  • Ischemic changes, LV hypertrophy
• Assess kidney function
  • Acute renal failure may be asymptomatic

Diagnosis Tests & Interpretation

Lab

• CBC
  • Anemia and thrombocytopenia are present in thrombotic microangiopathy
• Standard hospital protocols for chest pain
• BUN, creatinine
• Electrolytes
  • Hypokalemia present in primary mineralocorticoid excess
• Urinalysis:
  • Proteinuria, hematuria, and casts
• Urine toxicology screen:
  • If recreational drugs are suspected
• HCG

Imaging

• Chest x-ray:
  • If cardiopulmonary symptoms are present
• Head CT:
  • If headache, confusion, neurologic findings
• CTA chest and abdomen:
  • If concern for aortic dissection

Diagnostic Procedures/Surgery

• Arterial line
• Lumbar puncture:
  • Exclude subarachnoid hemorrhage

Differential Diagnosis

• Acute coronary syndrome (ACS)
• Acute heart failure (AHF)
• Aortic dissection
• Intracerebral hemorrhage (ICH)
• CVA (ischemic or hemorrhagic)
• Preeclampsia/eclampsia
• Withdrawal syndromes:
  • β-blockers
  • Clonidine (central α2-agonist)
• States of catecholamine excess:
  • Pheochromocytoma
  • Cocaine/sympathomimetic drug intoxication
  • Tyramine ingestion when on MAOIs

Treatment

Pre-Hospital

• ABCs
• Consider gentle BP reduction.

Initial Stabilization/Therapy

• ABC, cardiac monitoring, pulse oximetry
• Oxygen administration
• IV access

Ed Treatment/Procedures

• Hypertensive urgency:
  • No need to treat, but close follow-up
  • Use oral agents only
  • Give any missed home dose
  • Goal: Lower the BP gradually over 24-48 hr
• Hypertensive emergency:
  • Treat end-organ damage, not absolute BP
  • Reduce MAP by ≤20-25% in the 1st hr
  • Goal: Systolic ~160 mm Hg, diastolic ~100 mm Hg in 2-6 hr
  • Once BP stable with IV therapy, transition to oral therapy within 6-12 hr
  • More gradual reduction recommended in:
    • Acute ongoing injury to CNS
  • More rapid reduction recommended in:
    • Aortic dissection
• Hypertensive encephalopathy:
  • Goal: MAP lowered by max. 20% or to DBP 100-110 mm Hg within 1st hr then gradual reduction in BP to normal over 48-72 hr
  • Drug of choice: Nicardipine, clevidipine, or labetalol
• Ischemic stroke:
  • CPP = MAP - ICP
  • Decreased CPP from hypotension (low MAP) or cerebral edema (high ICP) may extend infarct
  • Treat only SBP >220 mm Hg or DBP >120 mm Hg
  • Lytic candidates should have BP lowered to <185/110 mm Hg
  • Goal: MAP lowered by no more than 15-20%, DBP not <100-110 mm Hg in first 24 hr
  • Goal post tPA: BP <180/105 mm Hg
  • Drug of choice: Nicardipine, clevidipine, or labetalol
• Hemorrhagic CVA or SAH:
  • Treat if SBP >180 mm Hg/DBP >100 mm Hg
  • Goal: MAP lowered by 20-25% within the 1st hr or SBP 140-160 mm Hg
  • Drug of choice: Nicardipine, clevidipine, or labetalol
  • Avoid dilating cerebral vessels with nitroglycerin or nitroprusside
• ACS:
  • Goal: MAP to 60-100 mm Hg
  • Drug of choice: Labetalol or esmolol in combination with nitroglycerin
  • Avoid: Hydralazine (reflex tachycardia) and nitroprusside ("coronary steal"�)
• AHF:
  • Goal: MAP to 60-100 mm Hg
  • Drug of choice nitroprusside or NTG with ACEI and/or loop diuretic
• Acute renal failure/microangiopathic anemia:
  • Goal: MAP lowered by 20-25% within 1st hr
  • Drug of choice: Nicardipine, clevidipine, or fenoldopam. For scleroderma renal crises ACEI are drugs of choice.
• Aortic dissection:
  • Reduce shear force (dP/dT) by reducing both BP and HR
  • β-blockade must precede any drug that may cause reflex tachycardia
  • Goal: SBP 100-120 mm Hg and HR <65 bpm within 1st 20 min
  • Drug of choice: Esmolol in combination with dihydropyridine CCB or nitroprusside
  • Consult vascular surgery if type A
• Sympathomimetics (pheochromocytoma, cocaine, amphetamines):
  • Goal: MAP lowered by 20-25% within 1st hr
  • Avoid pure β-blockade (α is left unopposed)
  • Drug of choice: Phentolamine or calcium channel blocker with benzodiazepine. Use clonidine in cases of clonidine withdrawal

• Preeclampsia:
  • Definition: SBP >140 or DBP >90 mm Hg with proteinuria (>300 mg/24 hr or a urine protein/creatinine >0.3 or dipstick 1+)
  • Occurs >20 wk gestation - 4 wk postpartum
  • Headache, vision changes, peripheral edema, RUQ pain
  • Complications: Eclampsia, HELLP
  • Goal: SBP 130-150 mm Hg and DBP 80-100 mm Hg
  • Drug of choice: Labetalol, nicardipine, hydralazine, magnesium
  • Consult Obstetrics
• Esmolol:
  • β1-blockade
  • Onset 60s, duration 10-20 min
  • Avoid in AHF, COPD, heart block
• Labetalol:
  • Combined α- and β-blocker
  • Onset 2-5 min, duration 2-6 hr
  • No reflex tachycardia due to β-blockade
  • Avoid in: COPD, AHF, bradycardia
• Clevidipine:
  • 3rd generation dihydropyridine CCB
  • Onset 2-4 min, duration 5-15 min
  • Elimination independent of liver/renal function
  • Avoid in allergies to soy or egg products, defective lipid metabolism, AFib
• Nicardipine:
  • 2nd generation dihydropyridine CCB
  • Onset 5-15 min, duration 4-6 hr
  • Avoid in: AHF, coronary ischemia
• Nitroglycerin:
  • Venous > arteriolar dilation
  • Onset 2-5 min, duration 10-20 min
  • Perfuses coronaries, decreasing ischemia
  • Causes reflex tachycardia, tachyphylaxis, methemoglobinemia
• Nitroprusside:
  • Short-acting arterial and venous dilator
  • Onset 3 s, duration 1-2 min
  • Complications:
    • Reflex tachycardia, "coronary steal"�, increase ICP
    • Cyanide toxicity after prolonged use
  • Avoid in pregnancy, renal failure (relative)
• Hydralazine:
  • Arteriolar dilator
  • Onset 5-15 min, duration 3-10 hr
  • Hypotensive effect may be less predictable
  • Safe in pregnancy
• Enalaprilat:
  • ACE inhibitor
  • Onset 0.5-4 hr, duration 6 hr
  • Avoid in: Pregnancy, AMI
• Fenoldopam:
  • Selective postsynaptic dopaminergic receptor agonist (DA1)
  • Onset 5-15 min, duration 1-4 hr
  • No reflex tachycardia
  • Maintains renal perfusion
  • Avoid in: Glaucoma
• Phentolamine:
  • α1-blocker, peripheral vasodilator
  • Onset 1-2 min, duration 10-30 min

Medication

• Clevidipine: 1-16 mg/h IV infusion
• Enalaprilat: 1.25-5 mg q6h IV bolus
• Esmolol: 80 mg IV bolus, then 150 μg/kg/min infusion
• Fenoldopam: 0.1-0.6 μg/kg/min IV infusion
• Hydralazine: 10-20 mg IV bolus
• Labetalol: 20-80 mg IV bolus q10min (total 300 mg); 0.5-2 mg/min IV infusion
• Nicardipine: 2-15 mg/h IV infusion
• Nitroglycerin: 5-100 μg/min IV infusion; USE NON-PVC tubing
• Nitroprusside: 0.25-10 μg/kg/min IV infusion
• Phentolamine: 5-15 mg q5-15min IV bolus

Follow-Up

Disposition

Admission Criteria

• All patients with end-organ damage
• ICU for cardiac and BP monitoring

Discharge Criteria

• Absence of end-organ damage
• Likely to be compliant with primary care
• Known history of HTN
• Reversible precipitating cause (e.g., medication noncompliance)
• Able to resume previous medication regimen
• Return with chest pain or headache

Followup Recommendations

Initiation of a suitable medication regimen under care of a primary care provider �

Pearls and Pitfalls

• Avoid IV agents for hypertensive urgency
• BP goal in hypertensive emergency is a reduction of the MAP by 20-25% within the 1st hr except in ischemic CVA and aortic dissection
• Avoid excessive or precipitous decrease in BP because it may exacerbate end-organ damage
• Avoid reflex tachycardia in aortic dissection
• Avoid unopposed α in catecholamine excess

Additional Reading

• Johnson �W, Nguyen �ML, Patel �R. Hypertension crisis in the emergency department. Cardiol Clin.  2012; 30(4):533-543.
• Marik �PE, Rivera �R. Hypertensive emergencies: An update. Curr Opin Crit Care.  2011;17:569-580.
• Ram �CV, Silverstein �RL. Treatment of hypertensive urgencies and emergencies. Curr Hypertens Rep.  2009;11(5):307-314.
• Rhoney �D, Peacock �WF. Intravenous therapy for hypertensive emergencies, part 1. Am J Health Syst Pharm.  2009;66(15):1343-1352.
• Rhoney �D, Peacock �WF. Intravenous therapy for hypertensive emergencies, part 2. Am J Health Syst Pharm.  2009;66(16):1448-1457.

See Also (Topic, Algorithm, Electronic Media Element)

• Acute Coronary Syndrome
• Acute Stroke
• Aortic Dissection
• Congestive Heart Failure
• Preeclampsia/Eclampsia
• Subarachnoid Hemorrhage

Codes

ICD9

• 401.9 Unspecified essential hypertension
• 437.2 Hypertensive encephalopathy

ICD10

• I10 Essential (primary) hypertension
• I67.4 Hypertensive encephalopathy

SNOMED

• 132721000119104 Hypertensive emergency (disorder)
• 50490005 Hypertensive encephalopathy (disorder)
• 443482000 hypertensive urgency (disorder)

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