Hypertensive crisis resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ayokunle Olubaniyi, M.B,B.S [2]

Definitions

• Hypertensive urgencies - These are severe elevations in blood pressure with no or minimal evidence of target organ damage. An example is a blood pressure of greater than 160/100 mmHg (stage 2 hypertension) associated with severe headache, shortness of breath, nosebleeds, or severe anxiety.

• Hypertensive emergencies - These are severe elevations in blood pressure, usually greater than 180/120 mmHg, complicated by evidence of impending or progressive target organ dysfunction. They warrant urgent blood pressure reduction by parenteral agents to prevent or limit target organ damage. This is a clinical diagnosis. Examples include: hypertensive encephalopathy, intracerebral hemorrhage, acute myocardial infarction, e.t.c.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

• All the causes of hypertensive emergencies are life-threatening.

Common Causes

• Medication noncompliance
• Stimulants - Cocaine, methamphetamine, phencyclidine
• Withdrawal syndrome from antihypertensives - beta blockers, clonidine
• Pheochromocytoma

Management

Characterize the symptoms: ❑ CNS - severe headache, dizziness, confusion, weakness/numbness, altered/LOC, difficulty speaking ❑ Eyes - pain, blurred/loss of vision ❑ Cardiopulmonary - chest pain, dyspnea ❑ Renal - hematuria, proteinuria, reduced urinary output ❑ Others - nausea/vomiting, severe anxiety, nosebleeds

Evaluate the patient: ❑ History PMH especially HTN Medications - dosages, compliance Recreational drug use - methamphetamine, cocaine, phencyclidine ❑ Physical Blood pessure - both arms Fundoscopy - papilledema, exudates, hemorrhages Neuro exam - mental status, focal neurological deficits Cardiopulmonary - signs of pulmonary edema Abdomen - pulsatile masses, tenderness, bruits Limbs - peripheral pulses

Order Labs: ❑ CBC ❑ BMP + Mg + PO4 ❑ Serum uric acid ❑ FLP ❑ FBS ❑ Urinalysis/culture ❑ Urine electrolytes, creatinine, protein ❑ Chest X-ray ❑ EKG, ECHO ❑ Renal USS + doppler

Further work-up: ❑ TSH, free T3, free T4 ❑ Serum cortisol ❑ Serum aldosterone ❑ Serum renin levels ❑ HbA1C ❑ 24-hr urinary catecholamine & metanephrine levels ❑ Serum parathyroid hormone levels ❑ Urine and serum toxicology screen ❑ Urine pregnancy test ❑ CT/MRI ❑ DMSA/DTPA scans (renal scars) ❑ ANA/ESR/CRP/anti-dsDNA/anti-smith/rheumatoid factor/p-ANCA/c-ANCA

Evidence of end organ damage (any of the symptoms above)

YES

NO

Hypertensive emergency (NB - Treat the patient and not the BP)

Hypertensive urgency

Admit ICU Close BP monitoring ↓ Intra-arterial BP monitoring in severely-ill patients ↓ Assess volume status - IV N/S if volume depleted to prevent precipitous fall in BP following administration of antihypertensives ↓ Commence IV antihypertensives based on patient's symptom ↓ Change IV meds to oral when BP is stable NB - Not more than 25% reduction in BP within the 1st hour; when BP is stable, reduce to 160/100-110 mmHg within the next 2-6 hours

Outpatient/Admit for observation Oral antihypertensives Clinical surveillance within the first few hours of commencing medications NB - Gradual BP reduction over 24 - 48 hours

Management of specific hypertensive emergencies

Worsening blood pressure

Good control Review old/start new medication Modify risk factors Close follow-up

Intravenous Antihypertensives

Drug	Dose	Onset of action	Duration of action	Special indication	Avoid use
Clevidipine	1 to 2 mg/h as IV infusion, max 16 mg/h	2-4 mins	5-15 mins	Most HE	-----
Enalaprilat	1.25–5 mg every 6 hrs IV	15–30	6–12 hrs	Acute left ventricular failure	AMI, renal impairment, pregnancy. No benefit in HE.
Fenoldopam	0.1–0.3 µg/kg per min IV infusion	<5 min	30 min	Most HE + renal insufficiency	Glaucoma or ↑ICP
Hydralazine	10–20 mg IV	10–20 min IV	1–4 hrs	Eclampsia; although labetalol or nicardipine is preferred	This should generally be avoided due to its unpredictable pharmacodynamics
Nicardipine	5–15 mg/h IV	5–10 min	1.5 - ≥4 hrs	Most HE esp post-op hypertension, aortic dissection & pregnancy	Acute heart failure. Caution with cirrhotics & coronary ischemia
Nitroglycerin	5–100 µg/min as IV infusion	2–5 min	5–10 min	Coronary ischemia, cardiogenic pulmonary edema	Not used for most HE
Nitroprusside	0.25–10 µg/kg/min as IV infusion	Immediate	1–2 min	Most HE; should be avoided due to its toxicity (cyanide toxicity)	Caution with ↑ICP, AMI, CAD, CVA, renal or hepatic impairment.
Esmolol	250–500 µg/kg/min IV bolus, then 50–100 µg/kg/min by infusion; may repeat bolus after 5 min or increase infusion to 300 µg/min	1–2 min	10–30 min	Aortic dissection, perioperative (to reduce reflex tachycardia)	Acute decompensated heart failure
Labetalol	20–80 mg IV bolus every 10 min 0.5–2.0 mg/min IV infusion	5–10 min	3–6 hrs	Most HE; used in combination with vasodilators to reduces reflex tachycardia	Acute decompensated heart failure, heart block, asthma, pheochromocytoma
Phentolamine	5–15 mg IV bolus	1–2 min	10–30 min	Catecholamine excess

• HE - Hypertensive emergencies

Oral Antihypertensives

Drug	Dose	Onset of action	Duration of action
Captopril	12.5 to 25 mg PO or SL, repeat as needed. max dose - 50 mg PO	5-15 mins	2-6 hrs
Clonidine	0.1-0.2 mg PO x 1, then 0.05 to 0.1 mg/1-2 hrs. Max dose - 0.6 to 0.7 mg	15-30 mins	2-8 hrs
Labetalol	200 mg PO, then 200 mg/hr until desired effect. Max dose - 1200 mg	2 hrs	4 hrs

• Other agents to consider include:

1. PO frusemide 20mg (repeat as necessary)
2. PO nifedipine SR 30mg, single dose
3. PO felodipine 5 mg, single dose

Management of Specific Hypertensive Emergencies

Hypertensive emergencies	Preferred agents	Note
Aortic dissection	Labetalol, nicardipine + esmolol, nitroprusside + esmolol or IV metoprolol	Administer beta blocker to control the heart rate before initiating a vasodilator e.g. nitroprusside Reduce BP to 120 mmHg within 20 minutes with protection against reflex tachycardia.
Acute pulmonary edema/systolic dysfunction	NTG + (Nicardipine, fenoldopam, or nitroprusside) + loop diuretic
Acute pulmonary edema/diastolic dysfunction	Low-dose NTG + (esmolol, metoprolol, labetalol, or verapamil) + loop diuretic
Acute coronary syndrome	NTG + (labetalol or esmolol)
Hypertensive emergency with ARF/CRF	Nicardipine or fenoldopam
Hypertensive encephalopathy	Nicardipine, labetalol, fenoldopam (if renally impaired), clevidipine, nitroprusside (only if necessary)	The BP should not be lowered by more than 25%
Pre-eclampsia/eclampsia	Labetalol or nicardipine
Sympathetic crisis/cocaine overdose	Benzodiazepine + (verapamil, diltiazem, or nicardipine); phentolamine or nitroprusside	Beta blockers should NOT be administered alone to prevent un-opposed alpha-adrenergic stimulation
Cerebrovascular accident	Nicardipine, labetalol, fenoldopam, or clevidipine	An expert's judgement is required to determine if the BP should be lowered.
Withdrawal of antihypertensive therapy e.g. clonidine or propanolol	Re-administer the discontinued drug; phentolamine, nitroprusside, or labetalol, if necessary

Dos

• Hypertensive emergencies are best managed with a continuous infusion of short-acting titratable antihypertensive agents.
• Both sublingual and intramuscular routes of drug administration should be avoided due to their unpredictable pharmacodynamics.
• Assess patients' volume status before commencing intravenous vasodilators to prevent/minimize precipitous fall in blood pressure.

Don'ts

• Don't consider nifedipine, nitroglycerin and hydralazine as first-line therapies in the management of hypertensive crises due to their potential toxicities and adverse effects.