SEVERE HYPERTENSION IN THE ED(BACK TO BASICS 2010)

Richard Dionne MD CCFP-EMAssistant Professor Emergency Medicine – University of OttawaAssociate Medical Director – Regional Paramedic Program for Eastern Ontario

Special Thanks : Dr Jason Frank

April 1st, 2010

Goals & Objectives

Differentiate malignant hypertension from secondary causes

Understand the principles of managing hypertension and the risks associated

Differentiate and identify the target-organ damage causes by hypertension emergencies

Definition

Essential hypertension > 140 systolic / > 90 diastolic

BP = CO X PVR Blood Pressure = Cardiac Output X Vascular Resistance

Autoregulation phenomenon overwhelmed

Rapid rate rise in MAP : Mean Arterial Pressure

MAP = 1/3 Systolic + 2/3 Diastolic

Vascular endothelial stress injury pattern

Causes

Severe uncontrolled Hypertension : > 180 systolic / > 120 diastolic

Hypertensive Emergency (Malignant):

Acute target organ damage / effect

Hypertensive Urgencies: At risk of short term end organ effect

Differential Diagnosis

Primary Hypertension Long standing, uncontrolled, drug withdrawal

Secondary HypertensionA- Increased cardiac output

Renal failure with fluid overload Acute renal disease Hyperaldosteronism

B-Increased vascular resistance Renovascular hypertension Pheochromocytoma Drugs (sympathomimetics, MOA,etc.) Cerebrovascular (CVA, ICH, SAH)

Renin-Angiotensin-Aldosterone

Renin produced by the kidneys stimulates the formation of angiotensin II, a potent vasoconstrictor.

DDX: Renal Artery Stenosis

In turn promotes aldosterone release and consequently the retention of Na+ & water.

Both increase in vascular resistance and intravascular volume will increase blood pressure.

Hyperaldosteronism

Na+ retention, water retention, increased CO

Hypernatremia & Hypokalemia typical

Primary: Adrenal adenoma / hyperplasia

Secondary: Cushing’s, exogenous mineralocorticoids

Pheochromocytoma

Tumour in the adrenal gland (medulla) Increase in catecholamines (epi, norepi)

Paroxysmal : HTN, HA, palpitations, diaphoresis, anxiety ... Not panic attacks!

Dx: urine metanephrines & vandillymandelic acid

Break Down

Malignant Hypertension & Emergencies

Hypertensive Urgencies

Severe Uncontrolled Hypertension

Malignant Hypertension

1% of patient with primary hypertension will go on to have an accelerated malignant phase

Severe Hypertension + End-organ damage

Denotes an elevated blood pressure with the presence of papilledema on fundoscopy

Grade 3: vascular injury with possible hemorrhages, cotton-wool spots, arterio-venous “nicking”

End-organ damage

CNS: Hypertensive encephalopathy / CVA

CVS: Cardiac ischemia / Pulmonary edema / Aortic

dissection

Renal: ARF

Heme: microangiopathic hemolytic anemia

End-Organ Effects

Clinical Evaluation

Focus on “End-organ compromise”: Headache, Chest pain, Dyspnea,Visual

disturbance, Change in mental status / confusion.

Potential drug interactions, compliance to RX, etc.

Examination: BP both arms with appropriate size cuff, fundoscopy, cardiac & neurological .

Work-up: CBC, Lytes, renal function, ECG, urine & CXR. May need CT-head / urine tox screen, etc.

Regulation Brain Vasculature Normal individual:

Adapts with cerebral vasoconstriction if BP rises, and vasodilation if BP drops...

Adaptation to a wide range of MAP changes

Chronic Hypertensive: Cannot adapt as well, so a rapid drop in BP will

cause drop in cerebral perfusion pressure, therefore a risk of cerebral ischemia ...

Caution with lowering the BP too fast !!!

Management

Goal

1- Decrease MAP 15-20% within 1 hour

2- Further reduction towards 160/100 mmHg within the following 6 hours

3- Gradual reduction to normal range over the next 24 hrs if the patient is stable

Treatment

Vasodilators: Nitroprusside:

0,25 – 10 ug/kg/min perfusion IV Vasodilator: decrease in MAP, afterload ,

preload & renal blood flow.

Adrenergic inhibitors: Labetolol:

20 – 80 mg IV q 10 min, then infusion prn Beta-blocker with an alpha blocking property,

reduces PVR with no reflex tachycardia...

Hypertensive Urgencies

Severe elevation in blood pressure that is not causing end-organ damage...

Goal Control within 24hrs Consider if Diastolic BP > 115 – 130

Oral regiment may be all that is needed Captopril : 6.25 – 25 mg q 6h Clonidine: 0,1 – 0,2 mg q 12 – 24 h Labetolol : 100 – 200 mg q 12 h

Severe Uncontrolled Hypertension

ClassificationStage 1: SBP 120-139 / DBP 80-89

“prehypertension”

Stage 2: > 160 / 100 Categorize according to risk profile...

Treatment regiment: Diuretics: older patients & African Americans ACE inhibitors: comorbidity, diabetes, etc. Beta-Blockers: cardiovascular disease, Hx: MI &

angina

Follow-up

Hypertensive Emergency & Malignant crisis:

Admission & IV start of treatment required Needs ICU & monitoring

Hypertensive urgencies & Uncontrolled severe hypertension:

Oral treament started in ER vs early outpatient , but mandatory close follow-up with primary care MD

Conclusion

Measure blood pressure appropriately

Most patient do not require emergent treatment for their hypertension in the ED

Severe hypertension = evaluate for end-organ effects

Rapid recognition & lowering of BP in hypertensive emergencies

Careful of over treating & risk of cerebral ischemia

Question?