What is the diagnostic approach for a patient with suspected hypertension?

Diagnostic Approach to Hypertension

Hypertension diagnosis requires elevated blood pressure measurements on at least two separate office visits, confirmed with out-of-office monitoring (ambulatory or home BP) when feasible, followed by systematic evaluation for target organ damage, cardiovascular risk stratification, and screening for secondary causes based on clinical features. 1, 2

Blood Pressure Measurement and Confirmation

Initial Office Measurements

• Measure BP in both arms using validated automated oscillometric devices; if difference >10 mmHg exists, use the arm with higher values for subsequent measurements 1
• Obtain multiple readings over at least two separate office visits separated by days to weeks, as single-visit diagnosis overestimates true prevalence by 12.6% 3
• Measure standing BP at 1 and 3 minutes in elderly patients, diabetics, and when orthostatic hypotension is suspected (defined as SBP drop ≥20 mmHg or DBP drop ≥10 mmHg) 1
• Document heart rate, as resting values >80 bpm independently predict cardiovascular events 1, 2

Out-of-Office Confirmation Strategy

The confirmation approach depends on initial BP level 1, 2:

• BP 120-159/70-99 mmHg: Confirm with ambulatory (ABPM) or home monitoring (HBPM) within 1 month before diagnosing hypertension 2
• BP 160-179/100-109 mmHg: Confirm within days to weeks with repeat office measurements or out-of-office monitoring 1, 2
• BP ≥180/110 mmHg: Immediately exclude hypertensive emergency; if absent, confirm diagnosis within days 2

Out-of-office monitoring is critical because it eliminates white coat hypertension and provides measurements closer to true ambulatory values 1, 4

Essential Initial Laboratory Workup

Required Basic Tests

All newly diagnosed hypertensive patients require 1, 2:

• Serum electrolytes: Sodium and potassium (hypokalemia suggests primary aldosteronism) 1, 2
• Renal function: Serum creatinine with estimated glomerular filtration rate (eGFR) 1, 2
• Metabolic assessment: Fasting glucose and lipid profile (total cholesterol, LDL, HDL, triglycerides) 1, 2
• Urinalysis: Dipstick test for protein, blood, and sediment 1, 2
• Urine albumin-to-creatinine ratio (UACR): Detects early kidney damage (≥30 mg/g indicates moderate-to-severe damage) 1, 2, 5
• 12-lead ECG: Screens for atrial fibrillation, left ventricular hypertrophy (using Sokolow-Lyon >3.5 mV or Cornell voltage >244 mV·ms), and ischemic heart disease 1, 2, 5

Optional Tests Based on Risk

• Thyroid-stimulating hormone (TSH): Simple screening for hypo/hyperthyroidism as remediable causes 1
• Serum uric acid: Elevated in 25% of hypertensive patients; treat if >6 mg/dL with gout symptoms 2
• Complete blood count and liver function tests 1, 2

Medical History: Key Elements to Elicit

Hypertension-Specific History

Document 1:

• Duration of hypertension, previous BP levels, and prior antihypertensive medications with tolerability
• Current medications that elevate BP: NSAIDs, steroids, cyclosporin, sympathomimetics, cocaine, oral contraceptives 1
• Adherence to treatment and reasons for non-adherence
• Dietary sodium intake, alcohol consumption, and physical activity level 1

Cardiovascular Risk Factors

More than 50% of hypertensive patients have additional risk factors that proportionally increase coronary, cerebrovascular, and renal disease risk 2, 5:

• Demographics: Age (men ≥55 years, women ≥65 years), male sex, family history of premature CVD (men <55 years, women <65 years) 1, 2
• Metabolic factors: Diabetes, dyslipidemia, obesity (BMI ≥30 kg/m²), abdominal obesity (waist >102 cm men, >88 cm women) 1, 2
• Lifestyle factors: Current smoking, excessive alcohol intake, sedentary lifestyle 1
• Established CVD: Prior myocardial infarction, heart failure, stroke/TIA, chronic kidney disease 1, 2

Symptoms Suggesting Secondary Hypertension

Screen for specific features indicating potentially correctable causes 1:

• Primary aldosteronism: Muscle weakness, tetany, cramps, arrhythmias from hypokalemia 1
• Pheochromocytoma: Episodic sweating, palpitations, headaches, pallor 1
• Obstructive sleep apnea: Snoring, daytime sleepiness, neck circumference >40 cm 1
• Renal artery stenosis: Flash pulmonary edema, abdominal bruit 1
• Cushing syndrome: Central obesity, facial rounding, easy bruising, purple striae 1
• Thyroid disease: Heat/cold intolerance, weight changes, palpitations 1

Target Organ Damage Symptoms

Ask about 1:

• Cardiac: Chest pain, shortness of breath, palpitations, peripheral edema
• Neurologic: Headaches, visual disturbances, dizziness, focal neurologic symptoms
• Renal: Nocturia, hematuria
• Vascular: Claudication

Physical Examination: Critical Findings

Cardiovascular Assessment

• Pulse: Rate, rhythm, character; assess radial-femoral delay (suggests coarctation) 1
• Cardiac exam: Apex beat displacement, extra heart sounds, basal crackles suggesting heart failure 1
• Vascular exam: Carotid, abdominal, and femoral bruits; peripheral edema 1
• Thigh BP measurement: Required in patients ≤30 years if brachial BP elevated; lower thigh pressure suggests coarctation 1

Signs of Secondary Hypertension

• Enlarged thyroid gland (thyroid disease) 1, 2
• Enlarged kidneys on palpation (polycystic kidney disease) 1
• Cushingoid features: Central obesity, moon facies, buffalo hump, purple striae 1
• Neck circumference >40 cm (obstructive sleep apnea) 1

Anthropometric Measurements

• BMI and waist circumference (targets: <94 cm men, <80 cm women) 2

Cardiovascular Risk Stratification

Risk Calculation

• Use validated risk scores: SCORE2 for ages 40-69 years or SCORE2-OP for ages ≥70 years to calculate 10-year CVD risk 2
• Patients with SCORE2/SCORE2-OP ≥10% are at increased risk warranting aggressive management 2

High-Risk Features Requiring Immediate Treatment

Identify patients who need treatment regardless of BP level 2:

• Established cardiovascular disease (prior MI, stroke, peripheral artery disease)
• Diabetes mellitus
• Chronic kidney disease (eGFR <60 mL/min/1.73m²)
• Familial hypercholesterolemia
• Age >65 years with multiple risk factors

Assessment for Hypertension-Mediated Organ Damage (HMOD)

Detection of HMOD is crucial because it reclassifies low-to-moderate risk patients to higher risk, mandating more intensive treatment 2, 5.

Cardiac HMOD

• Echocardiography: Indicated when ECG shows abnormalities or patient has cardiac symptoms 1, 2
  • Assesses left ventricular hypertrophy (LVM index: men >115 g/m², women >95 g/m²), systolic/diastolic dysfunction, atrial dilation 1, 5
  • Sensitivity 80-90% for LVH detection versus 10-30% for ECG 5
  • Provides superior risk stratification compared to ECG alone 5

Vascular HMOD

• Carotid ultrasound: Detects atherosclerotic plaques (intima-media thickness >0.9 mm) and stenosis when clinically indicated 1, 2
• Ankle-brachial index (ABI): Screen for peripheral artery disease; ABI <0.9 indicates significant disease 1, 2

Renal HMOD

• Renal ultrasound: Evaluate kidney size, parenchymal disease, and rule out obstruction when secondary hypertension suspected 1, 2
• UACR monitoring: Repeat at least annually if moderate-to-severe CKD diagnosed (eGFR 30-60 mL/min/1.73m²) 2

Ophthalmologic HMOD

• Fundoscopy: Mandatory in patients with BP >180/110 mmHg or suspected malignant hypertension 1, 2
  • Look for retinal hemorrhages, papilledema, arteriovenous nicking, cotton-wool spots 1
  • Also indicated in hypertensive patients with diabetes 2

Neurologic HMOD

• Brain CT/MRI: Obtain when neurologic symptoms present to detect ischemic or hemorrhagic injury, white matter lesions 1, 2

Screening for Secondary Hypertension

Secondary causes account for 20-40% of malignant hypertension cases but only 5-10% of all hypertension 2, 6. Screen when clinical features suggest underlying disease 1, 2.

Indications for Secondary Hypertension Workup

• Age <30 years or >55 years at onset 6
• Resistant hypertension (uncontrolled on 3 drugs including diuretic) 6
• Accelerated or malignant hypertension 6
• Hypokalemia (spontaneous or diuretic-induced) 1
• Abdominal bruit, asymmetric kidney size 1
• Specific clinical features noted above 1

Specific Tests for Secondary Causes

When indicated based on clinical suspicion 1, 2:

• Primary aldosteronism: Aldosterone-renin ratio (most common secondary cause)
• Pheochromocytoma: Plasma free metanephrines
• Cushing syndrome: Late-night salivary cortisol or 24-hour urinary free cortisol
• Renal artery stenosis: Renal artery Duplex ultrasound, CT/MR angiography
• Thyroid disease: TSH (already part of basic workup)

Common Diagnostic Pitfalls

• Single-visit diagnosis: Overestimates prevalence by 12.6%; always confirm with multiple visits 3
• White coat hypertension: Affects significant proportion; out-of-office monitoring essential for accurate diagnosis 1, 4
• ECG for LVH detection: Sensitivity only 10-30%; echocardiography far superior (80-90%) for risk stratification 5
• Ignoring orthostatic hypotension: Independently predicts mortality; measure standing BP in high-risk groups 1
• Missing secondary causes: Failure to recognize clinical clues delays diagnosis of treatable conditions 1
• Inadequate risk stratification: Not assessing HMOD leads to undertreatment of high-risk patients 2, 5