Essential hypertension is characterised by 3 abnormal readings and no symptoms of any underlying cause.
Essential hypertension is 20 times more common than secondary hypertension.
Blood Pressure Cutoffs
| Blood Pressure Cutoff | Population |
|---|---|
| BP > 130/90 (x3) | Cutoff for patients with Diabetes mellitus, renal disease, congestive heart failure, myocardial infarction, stroke, and peripheral artery disease |
| BP > 140/90 (x3) | Cutoff in otherwise healthy patients |
| BP > 160/110 (x3) | Cutoff for severe essential hypertension |
JNC Classification of Hypertension
Start with Normal. Add 20 to systolic and 10 to diastolic to reach the minimum BP required for the next stage. If it is an “or” statement – if either systolic or diastolic is in a stage, call it the highest qualified stage
| Systolic (mmHg) | Diastolic (mmHg) | Treatment | |
|---|---|---|---|
| Optimal | < 120 | and < 80 | Lifestyle and diet |
| Normal | 120 – 129 | or 80 – 84 | Lifestyle and diet |
| High normal | 130 – 139 | 85 – 89 | Lifestyle and diet |
| Stage 1 hypertension | 140 – 159 | or 90 – 99 | Monotherapy (ACEi /ARB > CCB) |
| Stage 2 hypertension | > 160 | or > 100 | Comorbid specific combination therapy (Thiazide + CCB or ACEi or Beta-blocker) |
| Stage 3 hypertension (Urgency) | >180 | or >110 | PO antihypertensive e.g. nifedipine |
| Emergency | Alarm symptoms | IV antihypertensive e.g. Labetalol | |
| Isolated systolic hypertension | >140 | < 90 | |
| Resistant hypertension | > 140 | > 90 | After treatment with 3 antihypertensives at optimal or best tolerated dose |
- Pathogenesis of essential hypertension
- Genetic factors
- Aldosterone synthetase (11-B-hydroxylase, 17-a-hydroxylase): Leads to increased secretion of aldosterone, causing salt and water retention, and plasma and volume expansion
- Angiotensin I and II receptor gene: Increased response of the ATI and ATII receptors causes vasoconstriction and an increase in TPR
- ENaC mutations (Liddle syndrome): Mutations affect the beta and gamma subunit of ENaC, causing increased sodium resorption and plasma volume expansion, also known as salt-sensitive hypertension
- Environmental factors → Increased TPR, Intravascular volume, and Cardiac output
- Stress: Stress causes increased Epinephrine and Norepinephrine → Epinephrine stimulates the RAAS and increases Cardiac output → Norepinephrine stimulates vasoconstriction and increases Total peripheral resistance
- Increase in vasoconstrictors
- Renin (RAAS): Renin → Angiotensinogen → AT I → AT II → Aldosterone
- Catecholamines: Increase Cardiac Output and Total Peripheral Resistance
- Endothelins: Vasoconstriction and increased Total peripheral resistance
- Sodium retention: RAAS, Liddle syndrome, Gitelman syndrome
- Genetic factors
- Evidence that Na+ plays a role in the pathogenesis of Hypertension
- Reduced Na+ results in Reduced BP
- Na+ losing diuretics cause a reduction in BP
- Increased intake of Na+ results in Increased BP
- There is increased Na+ in the intravascular space in Hypertension
- Genetically predisposed animals given a Na+ load develop Hypertension
- Initial treatment for non-comorbid patients
- Lifestyle modification (diet, exercise)
- ACEi/ARB or CCB, depending on the patient’s age
- Monitor for 3 to 6 months
- Indications for starting antihypertensives
- Stage I hypertension (ABPM/HBPM ≥ 135/85 mmHg)
- < 80 years with target organ damage, established cardiovascular disease, renal disease, diabetes, or 10-year cardiovascular risk equivalent to 20% or greater
- Stage II hypertension (ABPM/HBPM ≥ 150/95 mmHg)
- Start antihypertensive regardless of age
- Patients < 40 years
- Specialist referral to exclude secondary causes
- Stage I hypertension (ABPM/HBPM ≥ 135/85 mmHg)
- Treatment for severe essential hypertension (>160/110 x 3)
- Treatment of resistant hypertension (> 140/90 x 3 with 3 medications at optimal or best tolerated dose
- Seek expert advice
- Spironolactone if K+ < 4.5 mmol/L
- Higher dose thiazide-like diuretic if K+ > 4.5 mmol/L
- Consider an alpha- or beta-blocker if further diuretic therapy is not tolerated or is contraindicated
Individualized treatment
| Patient Group | Medications |
|---|---|
| Pregnant | Diuretics and RAAS inhibitors are contraindicated. Use methyldopa, labetaolol, or CCBs (nifedipine) |
| Diabetes | ACEi, ARB (goal <140/90) |
| African descent or ≥ 55 yo | CCB or Thiazide as first-choice (JNC-8 scrapped the recommendation for ARBs as first-line) |
| Congestive Heart Failure | BB + ACEi + ISDN + Hydralazine, Spironolactone |
| LDL > 100 | Add a statin (atorvastatin) |
| Coronary Artery Disease | BB, ACEi/ARB, ISMN, CCB |
| Cerebrovascular accident | ACEi |
| Chronic kidney disease | ACEi (Thiazides do not work after Cr > 1.5 mg/dL) |
| Benign prostatic hyperplasia | Alpha blocker |
| Depression and Asthma | Avoid Beta-blocker |
| Hyperthyroidism | Beta-blocker first |
| Osteoporosis | Thiazide |
Treatment goal
| Population | Clinic BP | ABPM/HBPM |
|---|---|---|
| Hypertension age < 80 years | < 140/90 mmHg | 135/85 mmHg |
| Hypertension age > 80 years | < 150/90 mmHg | 145/85 mmHg |
| Hypertension + Diabetes | <130/80 mmHg | |
| Hypertension + Kidney disease | < 130/80 mmHg |