3008 Naylor - Hypertension (9-12)

An elevated blood pressure above 140/90.

Primary (essential) 90-95% of cases, where there is NO known cause, only lots of associated risk factors, and changing one of these factors wont rid you of hypertension. Eg genetics, age, diet, stress, smoking etc.

Secondary: 5-10% of cases where the cause is known.

Yes, increasing your risk factors increases your chance of coronary heart disease.

Eg. Hypertension + raised cholestrol + smoking

Phaeochromocytoma: a tumour of the adrenal glands causing them to secrete higher levels of arenaline and noradrenaline leading to an increased blood pressure.

Renin-secreting tumour

Cushings disease: increased secretion of corticoids

Secondary hypertension is easier to treat as the cause is known.

See Image.

1) Hypertrophy: thickening of the media smooth muscle cells
2) Increase in collagen
3) and decrease in elastin causing stiffness

The thick and stiff artery walls make the artery less able to respond to changes in blood pressure eg during exercise.

In smaller arteries may also see fibrinoid necrosis which blocks the arteries and hence increases resistance.

Malignant hypertension is the terminal end phase of hypertension.

Such as HT retinopathy, sever ischaemia, thrombosis, and firinoid necrosis of the arterioles.

- Heredity
- Diet
- Age
- Obesity
- Stress
- Diabetes
- Smoking
- Alcohol Intake

These factors have an additive effect.

Hypertension can also be reduced by managing these risk factors.

See Imagae.

See Image.

The baroreceptor reflex: baroreceptor nerves notmally maintain homeostasis.

However in hypertension the baroreceptor reflex is reset to a new higher level.

We can cure hypertension by returning the baroreceptor reflex back to normal levels.

Increased salt intake increases blood pressure by retaining bodily fluids (increases extracellular fluid volume)

Very fine line: 3g of salt = hypertsion
1g of salt = no hypertension
Hence it is critical to stick between 1-3g of salt per day

Increased salt = Increased hypertension.

Unless you are genetically salt-resistant, then no hypertension.

The rice diet.

With one kidney clamped and other removed you see great hypertension - renin is not involved.

Whith one kidney clamped but the other still intact you see less hypertension (resembles renal artery stenosis)

When the two kidney model was injected with ACE inhibitor, the blood pressure droped dramatically, showing the involvement of renin in the two kidney model but not the one kidney model.

- The Kidney is the cause of hypertension. And hypertension involves resetting the pressure-diuresis relationship.

He suggested three possible causes for hypertension which are mutually exclusive:
1. Non renal: wrong
2. Non renal - Renal damage: wrong

3. Renal YES.