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 FrankApril 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?