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HYPERTENSIVE CRISIS      SX  |  RX  |  Causes         See also Hypertension   &  BP meds

Definition

• Severe elevation in blood pressure, with diastolic blood pressure (DBP) > 120-130 mmHg.
• Hypertensive Emergency is defined as a clinical setting where BP must be reduced effectively within minutes to <1hour, such as accelerated & malignant hypertension, hypertensive encephalopathy, & severe diastolic hypertension (120-160 mmHg) that is associated with acute pulmonary edema, ischemic chest pain, dissecting aortic aneurysm, or intracerebral hemorrhage,  papilledema (+/ ), evidence of renal function deterioration, or evidence of neurologic dysfunction, etc.
• Hypertensive Urgency is defined as a clinical setting of severe hypertension  with minimal or no symptoms, where severe elevation of BP are not causing immediate end-organ damage but should be effectively lowered within 24 hours to reduce potential risk to the patient.

Symptoms:

• Asymptomatic in some patients (ie. hypertensive urgency)
• Headache, Visual Changes, Papilledema
• Chest Pain (MI), Pain to Back (Dissection)
• Abdominal Pain - abdominal aneurysmal dissection
• Flank Pain - renal disease
• Mental Status Changes - stroke, leukoencephalopathy

RX:

Intravenous Drugs:
Sodium Nitroprusside

• Standard rapidly acting agent effective in many cases
• Dose is 0.25-8 µg/kg/minute as IV infusion, start with 0.3- 0.5 ug/kg/min (about 20-50 ug/min), then 1- 3 ug/kg/min IV (max:<10 ug/kg/min) (50 mg in 250 ml D5W)
• Onset: 0.5 -1 min ; Duration: 2 - 5 min
• Adverse effects: hypotension, N&V, apprehension, cyanide (thiocyanate level>10 mg/dl is toxic; >20 mg/dl may be fatal) toxicity convulsion, twitching, psychosis, dizziness, etc.
• Nitroprusside has decreased efficacy in renal failure
• Toxic levels of cyanide build up rapidly in patients with renal failure
• Nausea, vomiting, muscle twitching and sweating can occur

Nitroglycerin

• Highly effective in setting of coronary ischemia, acute coronary syndromes
• Dose is 5-100µg/min as IV infusion
  Nitroglycerin IV infusion start 5- 10 ug/min then may be up to >200 ug/min prn
  esp. in pts where Na nitroprusside is relatively contraindicated &
  in pts with ischemic heart disease, impaired renal or hepatic function.
  • Onset: immediate; Duration:1- 5 min
• May cause headache, tachycardia, vomiting, methemoglobinemia
• Excellent for titrating blood pressure in setting of coronary ischemia

Labetalol (Trandate)

• Mixed alpha/beta blocker, excellent for most hypertensive emergencies
• Dose is 20-80mg IV bolus every 10 minutes or 0.5-2mg/min infusion IV
  Start 20 mg IV, then 20- 80 mg q10 min prn, or start with 0.5 mg/min infusion, then 1- 2 mg/min (may be up to 4 mg/min) IV infusion up to 300 mg/d max.
  • Onset: 5 -10 min; Duration: 3- 6 h
  • Adverse effects: hypotension, bradycardia, dizziness, scalp tingling
• Avoid in patients with heart block, bradycardia, CHF, severe asthma or bronchospasm
• First or second line for eclampsia; excellent in catecholamine surges

Enalaprilat

• Intravenous formulation of enalapril (ACE inhibitor)
• Dose is 1.25-5.0mg q6 hour IV (duration of action ~6 hours)
• Onset of action in 15-30 minutes;  Duration 6 hours or more
• Highly variable response; precipitous BP drop in high-renin states, rarely angioedema, hyperkalemia, or acute renal failure.
• May be most useful in acute cardiogenic pulmonary edema
• Avoid in acute myocardial infarction

Diltiazem (Cardizem)

• Initial dose 0.25 mg/kg over 2 min, followed by infusion of 0.35 mg/kg at an initial rate of 10 mg/hour
• Onset:  3-30 min
• Adverse effects: excessive hypotension, flushing; rarely amblyopia

Hydralazine (Apresoline)

• Indicated primarily for eclampsia
• Dose is 10-50 mg IV or IM titrate to effect (onset <20 minutes, duration 3-8 hours)
  • Onset: 10- 20 min ;  Duration: 3 -8 h
  • Adverse effects: tachycardia, flushing, contraindicated in angina or aortic dissection
• Can be given IM as well, 10-50mg (onset 20-30 minutes)
• Tachycardia, flushing, headache, vomiting, increased angina may occur

Nicardipine  (Cardene)

• IV formulation available though not commonly used
• Dose is 5-15mg/hr IV, onset 5-10 minutes, duration 1-4 hours
• Do not use in acute CHF or with coronary ischemia
• May be most useful for hypertension in setting of subarachnoid hemorrhage

Esmololol (Breviblock®)

• Very short half life (2-4 minutes) non-selective ß-blockade
• Dose is 250-500µg/kg/min for 1 minute, then 50-100µg/kg for 4 minutes
• Sequence may be repeated, and continuous drip may be maintained
• Onset of action is 1-2 minutes; 10-20 minute duration
• Mainly for acute aortic dissection, perioperatively, acute coronary ischemia
• May be used with caution in acute MI with depressed LV to modulate heart rate
• Very close monitoring is required, and fluid load is large with this agent

Phentolamine

• Mainly for catecholamine surges (pure alpha-adrenergic blockade)
• Dose is 5-15mg IV; onset 1-2 minutes; duration 3-10 minutes
• Tachycardia, flushing and headache may occur

Diazoxide (Hyperstat) 300 mg IV bolus - ? obsolete ?

• Onset: 1 - 2 min
• Duration: 4 - 12 h
• Adverse effects: Na retention, hyperglycemia, tachycardia, palpitations, chest pains, sedation & somnolence

Oral Medications:
Clonidine (Catapres)

• 0.2 mg PO, followed by 0.1 mg/hr to total of 0.8 mg until the diastolic BP is <110 mmHg, or reduction in diastolic BP of 20 mmHg or more.
• Onset 30-120 min;  Duration 8-12 h
• Adverse effects: sedation, dry mouth, dizziness, orthostasis, bradycardia
• Contraindicated in pts with sinus bradycardia, sick sinus synd., or heart block.

Labetalol (Trandate)

• 200-300 mg PO, followed by 100-200 mg q8h
• Onset 1-2h;  Duration 12-24 h
• Adverse effects: bradycardia

• Encephalopathy: Nitroprusside, Labetolol, Diazoxide
• Cerebral Infarction: no treatment (hemorrhage control), Nitroprusside, Labetolol
• Myocardial Ischemia, Infarction: Nitroglycerine, Labetolol, ß-adrenergic blockers
• Acute Pulmonary Edema: Nitroprusside (or Nitroglycerin) and Loop Diuretic
• Aortic Dissection: Nitroprusside and ß-adrenergic blockers, Labetolol
• Eclampsia: Hydralazine, Labetolol, Diazoxide
• Acute Renal Insufficiency: Nitroprusside, Labetolol, Ca antagonists
• Funduscopic changes: Nitroprusside, Labetolol, Ca antagonists
• Hemolytic Anemia, Microangiopathic: Nitroprusside, Labetolol, Ca antagonists
• Posterior Leukoencephalopathy (rare) [3]
• Reversible syndrome usually occurs in setting of hypertension
• Responds to reduction in blood pressure
• MRI changes can be quite dramatic showing white matter abnormalities
• Sublingual nifedipine is unsafe and is not FDA approved for hypertensive crisis [4]

Causes of Hypertensive Crisis 

• Chronic hypertension with acute exacerbation (most common)
• Renovascular hypertension
• Parenchymal Renal Disease
  • Acute glomerulonephritis
  • Renal Infarction
  • Vasculitis
• Scleroderma Renal Crisis
• Drug Ingestion
  • Tricyclic anti-depressants
  • Monoamine Oxidase (MAO) Inhibitors
  • Cocaine
  • Amphetamines
• Anti-hypertensive drug withdrawal or failed compliance
  • Centrally acting anti-hypertensives (eg. clonidine)
  • Peripheral alpha blockers (eg. prazosin)
  • Beta-Blocker acute withdrawal
• Pre-eclampsia and Eclampsia
• Autonomic hyperactivity
  • Guillain-Barre Syndrome
  • Spinal Cord Injury
• Pheochromocytoma

       2006