Hypertension is a critical topic for the PEBC Evaluating Exam (EE) and Multiple Choice Questions (MCQ) section. This study guide will provide an in-depth look into hypertension, following the latest Canadian guidelines. We’ll explore definitions, risk factors, diagnosis, and treatment strategies, with a focus on the pharmacological and non-pharmacological management aligned with current clinical practices.
What is Hypertension?
Hypertension, or high blood pressure, is a condition where the blood pressure in the arteries is persistently elevated. Blood pressure is determined by the amount of blood the heart pumps and the resistance to blood flow in the arteries. When arteries are narrowed, the heart has to pump harder, leading to increased blood pressure.
Blood pressure is recorded as two numbers:
- Systolic blood pressure (SBP): Pressure in the arteries when the heart beats.
- Diastolic blood pressure (DBP): Pressure in the arteries between beats.
Classification of Blood Pressure (According to Canadian Guidelines)
- Normal: SBP < 120 mmHg and DBP < 80 mmHg
- Elevated: SBP 120-129 mmHg and DBP < 80 mmHg
- Hypertension Stage 1: SBP 130-139 mmHg or DBP 80-89 mmHg
- Hypertension Stage 2: SBP ≥ 140 mmHg or DBP ≥ 90 mmHg
Exam Tip:
Make sure to remember these categories for case-based scenarios in the PEBC. Expect questions where you’ll have to interpret patient blood pressure readings and classify them accordingly.
Types of Hypertension
- Primary (Essential) Hypertension:
- No identifiable cause.
- Accounts for 90-95% of cases.
- Risk factors include genetics, lifestyle factors, and aging.
- Secondary Hypertension:
- Caused by an underlying condition.
- Examples include chronic kidney disease, endocrine disorders (e.g., hyperaldosteronism, pheochromocytoma), or medication-induced hypertension (e.g., corticosteroids, NSAIDs).
Risk Factors for Hypertension
Understanding the risk factors for hypertension is crucial for both patient care and your exams. The main risk factors include:
- Age: Blood pressure tends to rise with age.
- Family History: Genetics play a role in hypertension.
- Obesity: Increased body mass puts more strain on the heart.
- Sedentary Lifestyle: Lack of physical activity contributes to weight gain and increased blood pressure.
- High Salt Diet: Excessive salt intake leads to fluid retention and elevated blood pressure.
- Smoking and Alcohol: Both smoking and heavy alcohol use increase blood pressure.
- Stress: Chronic stress can contribute to hypertension.
- Comorbid Conditions: Conditions like diabetes, chronic kidney disease, and sleep apnea are linked to hypertension.
Exam Tip:
When approaching case studies in the PEBC, consider how these risk factors contribute to both primary and secondary hypertension. You may be asked to identify risk factors based on patient history or recommend lifestyle modifications as part of a treatment plan.
Diagnosis of Hypertension
The diagnosis of hypertension is typically made based on the average of two or more blood pressure readings taken on separate occasions. The Canadian Hypertension Guidelines recommend ambulatory blood pressure monitoring (ABPM) or home blood pressure monitoring (HBPM) for more accurate assessments.
Diagnostic Tests:
- Routine Blood Pressure Measurement: In-office or clinic settings.
- ABPM: Provides a 24-hour profile of blood pressure, used for diagnosing “white coat hypertension” (elevated BP in clinical settings but normal elsewhere).
- HBPM: Patients measure blood pressure at home over several days.
Management of Hypertension
Non-Pharmacological (Lifestyle) Management
Non-pharmacological management plays a crucial role in hypertension control. It’s particularly important for patients with elevated blood pressure or Stage 1 Hypertension and can also reduce the need for medications in patients already on pharmacotherapy.
Key Lifestyle Changes:
- DASH Diet (Dietary Approaches to Stop Hypertension): Emphasizes fruits, vegetables, whole grains, and low-fat dairy. Lowers blood pressure by reducing sodium and increasing potassium, calcium, and magnesium intake.
- Sodium Restriction: Limit daily intake to less than 2,000 mg of sodium.
- Physical Activity: Regular aerobic exercise (30-60 minutes of moderate-intensity activity most days of the week) helps lower blood pressure.
- Weight Loss: Reducing body weight in overweight patients can significantly lower blood pressure.
- Alcohol Reduction: Limit consumption to 2 drinks per day for men and 1 drink per day for women.
- Smoking Cessation: Reducing smoking helps lower cardiovascular risk.
Exam Tip:
PEBC questions frequently test knowledge of lifestyle interventions. Be prepared to advise patients on non-pharmacological treatments, particularly in early-stage hypertension or in patients resistant to pharmacotherapy.
Pharmacological Management of Hypertension
Pharmacological treatment is usually initiated in patients with:
- Stage 2 Hypertension
- High cardiovascular risk (e.g., diabetes, coronary artery disease)
- End-organ damage (e.g., retinopathy, nephropathy)
The latest Canadian guidelines recommend several drug classes, with first-line options based on patient-specific factors.
1. Diuretics
First-line treatment for many patients.
Thiazide Diuretics (e.g., Hydrochlorothiazide, Chlorthalidone):
- Mechanism: Reduce blood volume by promoting sodium and water excretion.
- Use: First-line for older patients (>60 years), effective in low-renin populations.
- Side Effects: Hypokalemia, hyperglycemia, hyperuricemia (risk of gout).
- Monitoring: Electrolytes (potassium) and kidney function (eGFR).
2. ACE Inhibitors (ACEIs)
First-line for patients with diabetes, chronic kidney disease, or heart failure.
Common ACE Inhibitors: Enalapril, Ramipril, Lisinopril.
- Mechanism: Inhibit conversion of angiotensin I to angiotensin II, reducing vasoconstriction.
- Side Effects: Cough (due to bradykinin buildup), hyperkalemia, angioedema.
- Contraindications: Pregnancy, bilateral renal artery stenosis.
3. Angiotensin II Receptor Blockers (ARBs)
An alternative to ACEIs, particularly for those who develop a cough.
Common ARBs: Losartan, Valsartan, Candesartan.
- Mechanism: Block angiotensin II receptors, preventing vasoconstriction.
- Side Effects: Hyperkalemia, less risk of angioedema.
- Use: First-line in patients with diabetes, kidney disease, or heart failure who cannot tolerate ACEIs.
4. Calcium Channel Blockers (CCBs)
Especially effective in patients of African or Caribbean descent.
Dihydropyridines (e.g., Amlodipine, Nifedipine):
- Mechanism: Block calcium influx into vascular smooth muscle, causing vasodilation.
- Side Effects: Peripheral edema, dizziness, flushing.
Non-Dihydropyridines (e.g., Verapamil, Diltiazem):
- Affect both blood pressure and heart rate; used for arrhythmias.
- Side Effects: Bradycardia, constipation (especially with Verapamil).
5. Beta Blockers
Used as second-line agents unless there are specific indications like heart failure or post-myocardial infarction.
Common Beta Blockers: Metoprolol, Atenolol, Bisoprolol.
- Mechanism: Decrease heart rate and contractility, lowering blood pressure.
- Side Effects: Fatigue, bradycardia, bronchospasm (avoid in asthma).
- Use: Particularly beneficial in younger patients or those with concurrent heart disease.
6. Additional Agents
- Alpha Blockers (e.g., Doxazosin): Used for patients with resistant hypertension or benign prostatic hyperplasia (BPH).
- Centrally Acting Agents (e.g., Clonidine, Methyldopa): Rarely used due to side effects but may be useful in specific scenarios such as pregnancy (Methyldopa).
- Direct Vasodilators (e.g., Hydralazine, Minoxidil): Reserved for resistant hypertension. Often require concurrent use of a diuretic and beta blocker.
Combination Therapy
Patients with stage 2 hypertension or those who fail to reach target BP on monotherapy often require combination therapy. The Canadian Hypertension Guidelines recommend starting with two medications from different classes in these cases, such as:
- ACE Inhibitor/ARB + Thiazide Diuretic
- ACE Inhibitor/ARB + Calcium Channel Blocker
Monitoring and Follow-up
After initiating therapy, patients should have regular follow-ups to monitor blood pressure and assess for side effects. The goal of therapy is to achieve a target BP of <140/90 mmHg, or <130/80 mmHg in high-risk populations (e.g., diabetes, chronic kidney disease).
Hypertensive Emergencies and Urgencies
- Hypertensive Emergency: Severe elevation in BP (typically >180/120 mmHg) with acute target organ damage (e.g., encephalopathy, stroke, heart failure). Requires immediate IV therapy.
- Hypertensive Urgency: Severe elevation in BP without target organ damage. Treated with oral agents and close monitoring.
Key Takeaways for PEBC Exams
- Be familiar with blood pressure classification and diagnosis based on patient readings.
- Know the non-pharmacological interventions for hypertension management.
- Understand the first-line pharmacotherapy options, their mechanisms, and side effects.
- Be ready to manage hypertensive emergencies and urgencies.
By mastering these concepts, you’ll be well-prepared for hypertension-related questions in the PEBC exams!
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References:
Hypertension Canada Guidelines: https://guidelines.hypertension.ca/
Pharmacotherapy: A Pathophysiologic Approach (Dipiro): https://accesspharmacy.mhmedical.com/book.aspx?bookid=1861
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Disclaimer:
This blog post is intended as a study aid for students preparing for the PEBC exams and is not an official resource or endorsed by the Pharmacy Examining Board of Canada (PEBC). The information provided is based on current guidelines and best practices but should not replace official PEBC materials, textbooks, or clinical guidelines. Always refer to authoritative sources and consult professional advice for the most accurate and up-to-date information.