Who should undergo secondary hypertension screening?

Secondary Hypertension Screening: Who Should Be Evaluated

Screening for secondary hypertension is strongly recommended for patients with clinical indicators including resistant hypertension, early-onset hypertension, sudden onset or worsening of previously controlled hypertension, severe hypertension, and target organ damage disproportionate to the duration or severity of hypertension. 1, 2

Key Patient Groups Requiring Secondary Hypertension Screening

High-Priority Screening Groups

• Resistant hypertension: BP >140/90 mmHg despite three optimal-dose medications including a diuretic 1, 2
• Early-onset hypertension: Patients <30 years of age, especially without typical risk factors 2
• Sudden changes in BP control: Abrupt onset or worsening of previously controlled hypertension 1, 2
• Severe hypertension or hypertensive emergency 2
• Target organ damage: Disproportionate to the duration or severity of hypertension 1
• Onset of diastolic hypertension in older adults 1

Condition-Specific Clinical Indicators

Renal Parenchymal Disease (1-2% prevalence) 2

• History of urinary tract infections, obstruction, hematuria
• Urinary frequency and nocturia
• Analgesic abuse
• Family history of polycystic kidney disease
• Elevated serum creatinine
• Abnormal urinalysis
• Physical findings: Abdominal mass (polycystic kidney disease), skin pallor

Renovascular Disease (5-34% prevalence) 1, 2

• Resistant hypertension
• Hypertension of abrupt onset or worsening
• Flash pulmonary edema (atherosclerotic)
• Early-onset hypertension, especially in women (fibromuscular dysplasia)
• Physical findings: Abdominal systolic-diastolic bruit, bruits over other arteries

Primary Aldosteronism (8-20% prevalence in resistant hypertension) 1, 2

• Resistant hypertension
• Hypokalemia (spontaneous or diuretic-induced)
• Muscle cramps or weakness
• Incidentally discovered adrenal mass
• Obstructive sleep apnea
• Family history of early-onset hypertension or stroke
• Physical findings: Arrhythmias (with hypokalemia), especially atrial fibrillation

Obstructive Sleep Apnea (25-50% prevalence in resistant hypertension) 1, 2

• Resistant hypertension
• Snoring, fitful sleep, breathing pauses during sleep
• Daytime sleepiness
• Physical findings: Obesity, Mallampati class III-IV, loss of normal nocturnal BP fall

Medication and Substance-Related Secondary Hypertension

Patients taking the following medications should be screened 2:

• NSAIDs
• Oral contraceptives
• Sympathomimetics
• Corticosteroids
• Erythropoietin
• Cyclosporine and tacrolimus
• Alcohol and illicit drugs
• Herbal supplements
• Excessive licorice consumption

Screening Approach

Initial Evaluation for All Hypertensive Patients 2

• Complete blood count
• Fasting blood glucose
• Serum electrolytes
• Renal function tests
• Lipid profile
• Thyroid-stimulating hormone
• Urinalysis
• 12-lead ECG

Targeted Screening Based on Clinical Suspicion 1, 2

• Renal parenchymal disease: Renal ultrasound
• Renovascular disease: Renal Duplex Doppler
• Primary aldosteronism: Plasma aldosterone/renin ratio under standardized conditions
• Obstructive sleep apnea: Berlin Questionnaire, Epworth Sleepiness Score, overnight oximetry
• Thyroid disorders: TSH levels

Important Considerations

Timing of Screening

• Initial screening for primary aldosteronism is best done before starting potentially interfering antihypertensive drugs 3
• If interfering medications cannot be stopped, interpretation of test results must consider their presence 3

Referral Recommendations

• If screening is positive for a form of secondary hypertension, referral to a specialist with expertise in that form is reasonable for diagnostic confirmation and treatment 1
• Complex cases should be referred to specialized hypertension centers 2

Common Pitfalls to Avoid

• Missing primary aldosteronism: Often overlooked due to misconception that it requires hypokalemia, when up to 20% of resistant hypertension cases may be due to primary aldosteronism 1
• Inadequate screening: Failing to screen young patients or those with resistant hypertension 4
• Overlooking medication causes: Not reviewing all medications and substances that could contribute to hypertension 2
• Delayed diagnosis: Secondary hypertension can lead to irreversible vascular remodeling if not detected and treated early 5

Remember that while secondary hypertension affects approximately 10% of the general hypertensive population, the prevalence is much higher in specific subgroups, making targeted screening essential for early detection and management 1, 2.