Hypertensive CrisisHypertensive Crisis

Yuan Zhiming Department of Emergency Medicine

The General Hospital

Tianjin Medical University

Contents

● Introduction ● Epidemiology ● Etiology ● Pathogenesis ● Diagnosis ● Treatment ● Prognosis

Introduction

Classification of hypertension Hypertensive crisis Hypertensive urgency Hypertensive emergency

Stage 3 hypertension has also been called severe hypertension or accelerated hypertension

1. Classification of hypertension

systolic BP or diastolic BP （ mmHg ） （ mmHg ）Stage 1 140 ~ 159 90 ~ 99 Stage 2 160 ~ 179 100 ~ 109 stage 3 ≥180 ≥110

Hypertensive crisis refers to elevated blood pressure coupled with progressive or impending organ damage due to high blood pressure, usually characterized by a rise in DBP to greater than 120 to 130 mmHg. Hypertensive crisis comprises a spectrum of conditions, including hypertensive urgency and hypertensive emergency.

2. Hypertensive crisis

defined as an elevation of SBP (>220mmHg) and/or DBP (>125mmHg) without evidence of acute end-organ damage.

3. Hypertensive urgency

defined as a sudden increase in systolic and/or diastolic BP associated with end-organ damage of the CNS, the heart, or the kidneys.

4. Hypertensive emergency

The clinical differentiation between hypertensive emergency and hypertensive urgency depends on the presence of target organ damage, rather than the level of BP

Changes in mental status such as confusion or coma (encephalopathy)

Bleeding into the brain (stroke) Heart failure Chest pain (angina) Fluid in the lungs (pulmonary edema) Heart attack Aneurysm (Bulging blood vessel) Eclampsia (occurs during pregnancy)

Organ damage associated with hypertensive Organ damage associated with hypertensive emergency may include:emergency may include:

What is an aneurysmWhat is an aneurysm??

An aneurysm is a dilation (ballooning) of

part of the blood vessel. It usually causes no

symptoms unless it ruptures. A ruptured

aneurysm is often fatal.

Hypertensive Urgencies

Upper levels of stage 3 hypertension Papilledema Headache Shortness of breath Pedal edema

Hypertensive Emergencies

Hypertensive encephalopathyAcute aortic dissectionAcute pulmonary edema with respiratory failureAcute myocardial infarction/unstable anginaEclampsiaAcute renal failureMicroangiopathic hemolytic anemia

What is What is aortic dissectionaortic dissection??

An aortic dissection begins with a tear in the

inner layer of the aortic wall.When a tear

occurs in the innermost layer of the aortic

wall, blood is then channeled into the wall of

the aorta, separating the layers of tissues. It is

a life-threatening emergency.

(A) Normal blood flow. (B) Dissection occurs when the inner lining of the aorta tears and the blood flow ‘dissects’ between the layers of the aortic wall.

Epidemiology

Sixty million US inhabitants suffer from hypertension. The vast majority of these patients have essential hypertension.

Fewer than 1% of these patients will develop one or multiple episodes of hypertensive crises.

Preeclampsia is a pregnancy-related hypertension. It occurs in 7% of all pregnancies. of them, 70% are null-gravidas and 30% are multi-gravidas. In molar pregnancies, preeclampsia has been described in up to 70% of cases.

o Cerebral infarction 24.5%o Encephalopathy 16.3%o Intracerebral or subarachnoid hemorrhage 4.5%o Acute congestive heart failure with pulmonary edema 36.8%o Acute myocardial infarction or unstable angina 12% o Aortic dissection 2%o Eclampsia 4.5%

The most prevalent associated complicationsThe most prevalent associated complications

Etiology

Hypertensive crisis may occur in patients with no history of the condition or can be precipitated by noncompliance with medical therapy or diet, or both; or by inadequate treatment.

Common causes include 1. ARF 2. Acute CNS events 3. Drug-induced hypertension 4. Ingestion of tyramine-containing foods

or beverages during treatment with a monoamine oxidase inhibitor (MAOI)

5. Pregnancy-induced epilepsia 6. Pheochromocytoma

Pathogenesis

The exact mechanism of hypertensive crisis is not known. The majority of patients have known hypertension before the crisis, and the sudden rise in BP is often related to the underlying disease process as described above.

The pathophysiology

humoral vasoconstrictors release

systemic vascular resistance increases

severe elevations of BP

endothelial injury,fibrinoid necrosis of the arterioles

deposition of platelets and fibrin, a breakdown of the normal autoregulatory function

ischemia

vicious cycle

Diagnosis

Manifestations

•CNS compromise, identified by headache, blurred vision

•Change in mental status or coma

Hypertensive crisis can be manifested by any of the following symptoms, depending on the end-organ involved

1. Diagnosis

• ARF, identified by a sudden absence of urine output

• Catecholamine excess

• Cardiovascular compromise, identified by the chest pain of an acute coronary syndrome or aortic dissection

Certain tests will be given to monitor blood pressure and assess organ damage, including:

Physical Examination & Tests

• Regular monitoring of blood pressure • Eye exam(funduscopic examination) to

look for hemorrhages, exudates, and/or papilledema

• Blood and urine testing• Electrocardiogram

There is no predetermined criterion for the level of BP necessary to induce a hypertensive emegency (although in 1984, the JNC on Hypertension defined severe hypertersion as a DBP greater than 115mmHg)

The level of BP

The diagnosis is based on altered end-organ function and the rate of the rise in BP, not the level of BP

2. Initial Evaluation of the Patient With Hypertensive Crises

(1)The key to successful management of patients with severely elevated BP is to differentiate hypertensive emergencies from hypertensive urgencies

Inquiry should include the use of antihypertensive medications, monoamine oxidase inhibitors and recreational drugs

(2)This is accomplished by a targeted medical history and physical examination supported by appropriate laboratory evaluation

Funduscopic examination is mandatory in all cases to detect the presence of papilledema

In obese patients, appropriately sized cuffs should be used

The BP in all limbs should be measured by the physician

A complete blood cell count, electrolytes, BUN, creatinine, and urinalysis should be obtained in all patients presenting with hypertensive crises

A peripheral blood smear should be obtained to detect the presence of a microangiopathic hemolytic anemia

a chest radiograph, ECG, and head CT are useful in patients with evidence of shortness of breath, chest pain, or neurologic changes, respectively

An echocardiogram should be obtained to assess left ventricular function and evidence of ventricular hypertrophy

In many instances, these tests are

performed simultaneously with the

initiation of antihypertensive therapy

Treatment

Principle

Pharmacologic Management

Treatment in Special Situations

Hypertensive emergenciesHypertensive emergencies

Necessitate admission of the patient to the ICU

Require immediate control of the BP to terminate ongoing end-organ damage, but not to return BP to normal levels.

1. Principle

The goal of therapy is to decrease the pressure by no more than 25% within minutes to 1-2 h and then toward a level of 160/100 mmHg within 2-6 h; or the MAP is lowered by 20%-25%.

Excessive reductions in pressure may precipitate coronary, cerebral, or renal ischemia

During the first 24 h of treatment it is recommended that MAP be decreased by no more than 20%. Once the BP is stabilized, oral antihypertensive therapy is initiated to achieve BP values of less than 140/90 mmHg.

Intravenous Medications

(1) Vasodilators: such as Sodium Nitroprusside, nitroglycerin hydralazine, and diazoxide.

(2) Short-acting β-blockers: labetalol ,esmolol

(3) angiotensin-converting enzyme inhibitor(ACEI): enalaprilat

(4) Diuretic: furosemide

Hypertensive urgenciesHypertensive urgencies

BP is lowered gradually over a period of 24 to 48 h

Usually treated with rapid-acting oral antihypertensive agents

not necessitate admission to ICU

Oral drugs can be prescribed Such as

(1) ACEI: Captopril (2) β-blockers: labetalol. (3) Clonidine guanabenz, prazosin, and

minoxidil. (4) Loop diuretic: is generally prescribed

in addition to the antihypertensive agents.

2. Pharmacologic Management

• Angiotensin-converting enzyme (ACE) inhibitors

• Angiotensin receptor blockers (ARBs) • Diuretics • Beta-blockers • Calcium channel blockers

Drugs commonly used to treat hypertension:

•Agents that can be administered IV that are rapid acting, are easily titratable, and have a short half-life are recommended

• The immediate goal of IV therapy is to reduce the diastolic BP by 10 to 15%, or to about 110 mmHg. In patients with acute aortic dissection, this goal should be achieved within 5 to 10 min. In the other patients, this end point should be achieved within 30 to 60 min. Once the end points of therapy have been reached, the patient can be started on a regimen of oral maintenance therapy.

• In patients who have suffered a major cerebrovascular event, the BP should not be lowered, except in exceptional circumstances.

 

Triage Evaluation: Algorithm  Group I-High BP Group II-Urgency GroupIII-Emergency

BP >180/110 >180/110 Usually >220/140

Symptoms Headache, anxiety; often asymptomatic

Severe headache, shortness of breath

Shortness of breath, chest pain, nocturia, dysarthria, weakness, altered consciousness

Examination No target organ damage, no clinical cardiovascular disease

Clinical cardiovascular disease present/stable

Encephalopathy, pulmonary edema, renal insufficiency, cerebrovascular accident, cardiac ischemia

Therapy Observe 1-3 hrs; initiate/resume medication; increase dosage of inadequate agent

Observe 3-6 hours; lower BP with short acting oral agent; adjust current therapy

Baseline laboratory tests; intravenous line; monitor BP; may initiate parenteral therapy in emergency room

Plan Arrange follow-up <72 hours; if no prior evaluation, schedule appointment

Arrange follow-up evaluation <24 hours

Immediate admission to ICU; treat to initial goal BP; additional diagnostic studies

Oral agents for treatment of hypertensive crisis

Agent Dose Onset/Duration of Action

Precautions

Captopril 25 mg PO repeat as needed;SL, 25 mg

15-30 min/6-8 hrSL 10-20 min/2-6 hr

Hypotension, renal failure in bilateral renal artery stenosis

Clonidine 0.1-0.2mg PO, repeat hourly as required to total dose of 0.6 mg

30-60 min/8-16 hr Hypotension, drowsiness, dry mouth

Labetalol 200-400mg PO, repeat every 2-3 hr

1-2 hr/2-12 hr Bronchoconstriction, heart block, orthostatic hypotension

Prazosin 1-2 mg PO, repeat hourly as needed

1-2 hr/8-12hr Syncope (first dose), palpitations, tachycardia, orthostatic hypotension

Min=minutes; hr=hour(s); PO=by mouth; SL=sublingual

Parenteral drugs for treatment of hypertensive emergency

Agent Dose Onset/Duration of Action

Precautions

Parenteral Vasodilators

Sodium nitroprus-side

0.25-10 µg/kg/min as IV infusion

Immediate/2-3 min after infusion

Nausea, vomiting; with prolonged use may cause thiocyanate intoxication, methemoglobinemia, acidosis, cyanide poisoning; bags, bottles, and delivery sets must be light resistant

Nitroglyc-erin

5-100µg as IV infusion 2-5 min/5-10 min Headache, tachycardia, vomiting, flushing, methemoglobinemia; requires special delivery system due to drug binding to PVC tubing

Nitroglycerin 5-100µg as IV infusion* 2-5 min/5-10 min Headache, tachycardia, vomiting, flushing, methemoglobinemia; requires special delivery system due to drug binding to PVC tubing

Nicardipine 5-15 mg/hr IV infusion 1-5 min/15-30 min, but may exceed 12 hr after prolonged infusion

Tachycardia, nausea, vomiting, headache, increased intracranial pressure; hypotension may be protracted after prolonged infusions

Diazoxide 50-150 mg as IV bolus, repeated or 15-30 mg/min by IV infusion

2-5 min/3-12 hr Hypotension, tachycardia, aggravation of angina pectoris, nausea and vomiting, hyperglycemia with repeated injections

Fenolda-pam mesylate

0.1-0.3 µg/kg/min IV infusion

<5 min/30 min Headache, tachycardia, flushing, local phlebitis, dizziness

Hydrala-zine

5-20 mg as IV bolus or 10-40 mg IM; repeat every 4-6 hr

10 min IV/>1hr (IV) 20-30 min IM/4-6 hr (IM)

Tachycardia, headache, vomiting, aggravation of angina pectoris, sodium & water retention and increased intracranial pressure

Enalapr-ilat

0.625-1.25 mg every 6 hr IV

Within 30 min/12-24 hr Renal failure in patients with bilateral renal artery stenosis, hypotension

Parenteral Adrenergic Inhibitors

Labetalol 20-40 mg as IV bolus every 10 min; up to 2 mg/min as IV infusion

5-10 min/2-6 hr Bronchoconstriction, heart block, orthostatic hypotension, bradycardia

Esmolol 500µg/kg bolus injection IV or 50-100µg/kg/min by infusion. May repeat bolus after 5min or increase infusion rate to 300 µg/kg/min

1-5 min/15-30 min First-degree heart block, congestive heart failure, asthma

Phentolam-ine

5-10 mg as IV bolus 1-2 min/10-30 min Tachycardia, orthostatic hypotension

hr=hour(s); min=minute; IV=intravenous; IM=intramuscular; PVC=polyvinyl chloride

3.Treatment in Special Situations

Acute Aortic Dissection

Hypertension After a Cerebrovascular Accident

Preeclampsia

Hypertensive Crises in End-Stage Renal Disease

Acute Aortic Dissection

•This condition requires a reduction of the shear force affecting the aorta

•Agents that cause a reflex increase in cardiac output should be avoided

• The agent of choice for treatment of aortic dissection is nitroprusside, almost always in conjunction with a beta-adrenergic blocking agent such as esmolol

• Most experts advise against lowering blood pressure in acute stroke patients without hypertensive encephalopathy or other cardiovascular emergencies that require the immediate lowering of blood pressure

Hypertension After a Cerebrovascular Accident

•Centrally acting agents should also be avoided because of their potential to interfere with mental status.

• Magnesium sulfate is considered the standard of therapy as a prophylaxis for seizure activity

Preeclampsia

• Hydralazine has been used traditionally in the treatment of eclampsia

• Once the patient is admitted to an ICU, labetalol or nicardipine is preferred

• Calcium channel blockers have been used for these patients with some success

• Patients may require emergent ultrafiltration in order to control the BP

Hypertensive Crises in End-Stage Renal Disease

● Hypertensive crisis that is not managed over the long term is associated with a 25% mortality 1 yr after the event, and 50% mortality 5 yr after the event.

● The most common causes of death are uremia, AMI, HF, cerebrovascular accident.

Prognosis

Questions

Explanation of terms:

Hypertensive crisis; hypertensive

urgency; hypertensive emergency

The principles of treatment of

hypertensive crisis