Hypertension: Pathophysiology, Assessment, and Management (Case Study)

Hypertension: Case Study Overview

This study guide summarizes the key concepts, pathophysiology, assessment, and management of hypertension (HTN), using a clinical case as context. Hypertension is a chronic medical condition characterized by persistently elevated blood pressure, which increases the risk of cardiovascular, renal, and other systemic complications.

Case Summary

• Patient: 64-year-old African-American female

• History: 7 years of hypertension, morning headaches, general weakness, prior non-compliance with blood pressure medications due to side effects

• Medications: Atenolol (100 mg), Hydrochlorothiazide (HCTZ, 12.5 mg), later captopril (ACE inhibitor), then losartan (ARB)

• Comorbidities: Obesity, diabetic retinopathy, diabetes mellitus (25 years), hyperlipidemia

Pathophysiology of Hypertension

Blood Pressure Regulation

Blood pressure (BP) is determined by the interaction of cardiac output (CO) and systemic vascular resistance (R):

• Cardiac Output (CO): The volume of blood the heart pumps per minute.

• Systemic Vascular Resistance (R): The resistance to blood flow in the blood vessels.

Formula:

$BP = CO \times R$

• Increased BP can result from increased CO, increased R, or both.

• In healthy individuals, an increase in one is often compensated by a decrease in the other.

• Antihypertensive medications typically lower either CO, R, or both.

Long-Term Regulation

• Kidneys: Play a central role in long-term BP regulation by controlling fluid and electrolyte balance.

• Renin-Angiotensin-Aldosterone System (RAAS): Regulates blood volume and systemic resistance.

• Baroreceptors: Sense changes in BP and mediate short-term adjustments.

See diagram for integrated regulation (central, renal, vascular, and hormonal mechanisms).

Assessment of Hypertension

Clinical Assessment

• Vital Signs: BP 180/94 mmHg (Stage II), HR 88 bpm, RR 18/min

• Physical Findings: Obesity, diabetic retinopathy

• Laboratory Findings:

  • BMI: 30.9 (obese)

  • Total cholesterol: 268 mg/dL (elevated)

  • Triglycerides: 230 mg/dL (elevated)

  • Fasting glucose: 105 mg/dL (impaired fasting glucose)

• Risk Factors: Diabetes, obesity, hyperlipidemia, non-compliance with lifestyle modifications

Target Organ Damage

• Heart: Left ventricular hypertrophy, heart failure

• Brain: Stroke, transient ischemic attack

• Kidneys: Chronic kidney disease, proteinuria

• Eyes: Hypertensive retinopathy

Pharmacological Management

Common Antihypertensive Drug Classes

Drug Class	Example	Mechanism of Action	Common Side Effects
Beta-blockers	Atenolol, Metoprolol	Decrease heart rate and cardiac output	Bradycardia, fatigue, dizziness, erectile dysfunction
Thiazide diuretics	Hydrochlorothiazide (HCTZ)	Increase renal excretion of sodium and water	Hypokalemia, increased blood sugar, orthostatic hypotension
ACE inhibitors	Captopril	Block conversion of angiotensin I to II, decrease resistance	Cough, angioedema, hyperkalemia
Angiotensin receptor blockers (ARBs)	Losartan	Block angiotensin II receptors, decrease resistance and volume	Dizziness, hyperkalemia, less cough than ACE inhibitors
Calcium channel blockers	Nifedipine, Diltiazem	Relax vascular smooth muscle, decrease resistance	Edema, headache, flushing

Special Considerations in African-American Patients

• Higher prevalence (40% higher than other groups)

• Earlier onset and greater risk of end-stage renal disease (ESRD), stroke, and cardiovascular mortality

• Respond better to thiazide diuretics and calcium channel blockers

• Beta-blockers and ACE inhibitors are less effective as monotherapy

Non-Pharmacological Management

• Lifestyle modifications: weight loss, dietary changes (DASH diet), reduced sodium intake, increased physical activity

• Smoking cessation

• Alcohol moderation

• Patient education and adherence support

Patient Education and Discharge Instructions

• Importance of medication adherence

• Monitor for side effects (e.g., dizziness, orthostatic hypotension)

• Change positions slowly to prevent falls

• Set realistic exercise and weight loss goals

• Enroll in smoking cessation programs if needed

Summary Table: Antihypertensive Drug Effects and Side Effects

Drug	Main Effect	Common Side Effects
Atenolol/Metoprolol	↓ HR, ↓ BP	Bradycardia, fatigue, dizziness, ED
HCTZ	↓ BP via diuresis	Hypokalemia, ↑ blood sugar, orthostatic hypotension
Captopril	↓ Resistance	Cough, angioedema, hyperkalemia
Losartan	↓ Resistance, ↓ volume	Dizziness, hyperkalemia
Nifedipine/Diltiazem	↓ Vascular resistance	Edema, headache

Key Points for Exam Preparation

• Understand the pathophysiology and risk factors for hypertension

• Know the mechanisms, indications, and side effects of major antihypertensive drug classes

• Recognize the importance of lifestyle modifications and patient education

• Be aware of special considerations in different populations (e.g., African-Americans)

• Interpret basic clinical and laboratory findings in hypertensive patients

Additional info: The provided notes are primarily medical/nursing in focus, but the pathophysiology, risk factors, and behavioral interventions are relevant for health psychology and biopsychology students. The content is not directly psychological but can be used in a health psychology context.