Definitions

There are 2 general types of Hypertension:

  • Essential Hypertension: where there is an absence of identifiable secondary cause. This accounts for ~95% of all cases of hypertension. Also referred to as primary or idiopathic hypertension. It is a heterogeneous disorder with numerous risk factors including sedentary lifestyle, obesity, insulin resistance (metabolic syndrome), salt/sodium sensitivity, alcohol intake, age, family history.

  • Secondary Hypertension: where hypertension can be attributed to an identifiable cause (e.g. aldosteronism, hyperthyroidism, glucocorticoid excess, renovascular disease, renal failure, pheochromocytoma).

Modifiable risk factors

Excess body weight

  • maintaining a normal body weight (BMI of 18.5-24.9) is recommended

  • 10 kg  of weight loss will reduce SBP by 5-20 mm Hg.

  • Mechanisms involved with obesity-induced hypertension include:↑leptin, ↑RAS activity including ↑sympathetic activation, ↑Na & fluid retention & endothelial dysfunction.

Excess dietary sodium intake

  • mean sodium intake is ~4100 mg/day for men & 2750 mg/day for women.

  • 75% comes from processed foods (e.g. canned foods, potato chips, ham, sausage, pizza).

  • ideally sodium should be reduced to <1500 mg/day, but aim for at least 1000 mg/day reduction in most adults.

  • increase potassium dietary intake to 3500-5000 mg/day by consumption of a diet rich in potassium.

  • a 1600 mg sodium DASH eating plan has been found to exert BP lowering effects similar to single drug therapy.



    Aerobic physical inactivity

  • aerobic activity such as brisk walking at least 30 mins/day most days of the week can lower SBP by 4-9 mm Hg.

    Excess alcohol intake

  • more than 2 drinks/day for men & 1 drink/day in women can significantly raise SBP (~2-4 mm Hg on average).

  • 1 drink = 0.5 oz or 15 ml ethanol (~12 g ethanol), 1.5 oz 80 proof whiskey, 5 oz wine or 12 oz beer.

  • The increase in blood pressure is approximately 1 mm Hg for each 10 g/day of alcohol consumed (and is largely reversible within 2-4 weeks of abstinence).




The consequences of chronic hypertension.

Vessel wall changes 

  • Ischaemia ( CAD, PVD) 
  • Plaque rupture
  • Aneurysms
  • Dissection 

Target organ damage •

  • Downstream: –Eye: Hypertensive retinopathy–Brain: Haemorrhage, Infarction and dementia–Kidney: Nephrosclerosis→ CKD
  • Upstream: –Heart: LVH → HFpEF →HFrEF