What are the causes and management options for diastolic hypertension in patients with a family history of hypertension, who may be overweight, physically inactive, or have a history of cardiovascular disease, kidney disease, sleep apnea, or thyroid disorders?

Causes of Diastolic Hypertension

Diastolic hypertension results from a combination of modifiable lifestyle factors and underlying medical conditions, with obesity, physical inactivity, excessive alcohol and salt intake being the most common reversible causes, while obstructive sleep apnea is the most prevalent secondary cause in resistant cases. 1, 2

Primary (Essential) Causes

Modifiable Risk Factors

• Obesity and excess body weight - Energy intake exceeding expenditure leading to elevated diastolic pressure 1
• Physical inactivity - Sedentary lifestyle contributes directly to elevated diastolic blood pressure 1
• Excessive alcohol consumption - Intake >21 units/week in males or >14 units/week in females raises diastolic pressure 1
• High sodium intake - Excessive salt consumption elevates diastolic blood pressure 1
• Smoking - Tobacco use increases cardiovascular risk and contributes to hypertension 1

Non-Modifiable Risk Factors

• Family history of hypertension - Strong genetic predisposition increases risk 1
• Age - Diastolic pressure tends to rise until middle age, then may plateau or decline 3, 4
• Male sex - Higher risk compared to premenopausal women 1

Secondary Causes (Identifiable Underlying Conditions)

Most Common Secondary Cause

• Obstructive sleep apnea - Present in 64% of patients with resistant hypertension, making it the single most common secondary cause 2
  • Predictors include: age >50 years, neck circumference ≥41 cm (women) or ≥43 cm (men), and presence of snoring 2
  • Associated with obesity and increased cardiovascular risk 1

Endocrine Disorders

• Primary aldosteronism - Found in 5.6% of resistant hypertension cases 2
  • Suspect with hypokalemia, muscle weakness, tetany, cramps, or arrhythmias 1
• Thyroid disorders - Both hyperthyroidism and hypothyroidism can elevate blood pressure 1, 2
• Cushing syndrome - Excess cortisol causes hypertension 1, 2
  • Look for fatty deposits, colored striae, increased BMI/waist circumference 1
• Pheochromocytoma - Rare but important cause 1, 2
  • Suspect with sweating, palpitations, and frequent headaches 1

Renal Causes

• Chronic kidney disease - Renal parenchymal disease found in 1.6% of resistant hypertension 1, 2
  • Elevated serum creatinine, reduced eGFR, proteinuria, or hematuria 1
• Renovascular hypertension/renal artery stenosis - Present in 2.4% of resistant cases 1, 2
  • Suspect with flash pulmonary edema or sudden onset/worsening of hypertension 1

Cardiovascular Causes

• Coarctation of the aorta - Congenital narrowing causing hypertension 1
  • Check for radio-femoral delay and blood pressure differential between arms and legs 1
• Increased aortic stiffness - Age-related arterial stiffening elevates systolic more than diastolic pressure 4

Medication and Substance-Related

• Oral contraceptives - Found in 1.6% of resistant hypertension cases 2
• Nonsteroidal anti-inflammatory drugs (NSAIDs) - Common cause of drug-induced hypertension 1
• Stimulants and drugs of abuse - Cocaine, amphetamines, other stimulants 1
• Caffeine - Can acutely raise blood pressure 1
• Alcohol abuse - Binge drinking particularly problematic 1

Other Conditions

• Metabolic syndrome - Cluster of insulin resistance, dyslipidemia, obesity, and hypertension 1
• Diabetes mellitus - Associated with increased hypertension risk 1
• Dyslipidemia - Elevated cholesterol and triglycerides often coexist 1

Clinical Evaluation Approach

When to Suspect Secondary Causes

• Resistant hypertension - Failure to control BP despite 3+ drugs including a diuretic 1, 2
• Sudden onset or worsening of previously controlled hypertension 1
• Young age at presentation (<30 years) 1
• Severe hypertension (diastolic >110 mmHg) 1
• Electrolyte abnormalities - Particularly hypokalemia suggesting aldosteronism 1
• Target organ damage disproportionate to BP elevation 1

Essential Investigations

• Urine dipstick for blood and protein 1, 5
• Serum electrolytes, creatinine, and eGFR 1, 5
• Blood glucose and lipid profile 1, 5
• 12-lead ECG to detect left ventricular hypertrophy 1, 5
• Consider aldosterone-renin ratio if hypokalemia or resistant hypertension 1
• Sleep study if obesity, large neck circumference, or snoring present 1, 2

Critical Clinical Pitfalls

• Failing to screen for obstructive sleep apnea in overweight patients with resistant hypertension, despite it being the most common secondary cause 2
• Not measuring standing BP in elderly or diabetic patients to exclude orthostatic hypotension before treatment 1
• Overlooking medication-induced hypertension from NSAIDs, oral contraceptives, or stimulants 1
• Assuming poor compliance without systematic evaluation for secondary causes in resistant cases 1
• Missing renovascular disease in patients with flash pulmonary edema or sudden BP worsening 1
• Not considering white coat hypertension - confirm with multiple measurements or ambulatory monitoring before diagnosing 1, 5, 6