1. CAUSES OF
HYPERTENSION
Types of hypertension
There are two broad types:
1. Primary or essential hypertension has no clear underlying
cause but appears to be the result of an interplay of
complex genetic and environmental factors.
2. Secondary hypertension is caused by a specific underlying
mechanism usually involving kidneys or endocrine system
2. Mechanisms in primary hypertension
Several patho-physiological mechanisms contribute
to the development of primary hypertension.
The factors include:
oGenetics ; Genes in the RAAS
oHigh salt intake ; Increase sodium and water
retention
oLow physical activity ; Accumulate excessive fat
,increase peripheral vascular resistance
oObesity ; insulin resistance, increase in vascular
resistance
3. oInsulin resistance ; Increased and peripheral
resistance
oRenin – angiotensin system; Fluid retention
oSympathetic nervous system; Peripheral
vasoconstriction and systemic vascular resistance.
oIntrauterine nutrition and low birth weight;
Increased sensitivity to glucocorticoids, structural
changes in blood vessels and kidneys resulting in
impaired endothelial development and impaired
renal devt respectively
4. Causes of secondary hypertension
These are unusual but are important because the
cause may be curable:
1. Endocrine causes:
oCushing‟s syndrome ;glucocorticoids activate RAAS,
can cross react and activate mineralocortcoids,
suppress vasodilatory systems.
oConn‟s syndrome; hyperaldosteronism-increased
sodium retention.
oPhaeochromocytoma; increased catecholamine
activity
5. oHyper / Hypothyroidism ; ↑ T3 activity
oAcromegaly ; ↑GH,hyperthyroidism,insulin
resistance.
oHyperparathyroidism; hypercalcaemia
oExogenous hormones,
e.g. contraceptive pills, glucocorticoids; estrogen
stimulates hepatic production of angioteninogen
7. 3.Other causes:
oCoarctation of the aorta
oPregnancy associated hypertension e.g preeclampsia
oAlcohol
oAcute stress.
oSmoking.
oSeep apnoea
oAge related
DR AGABA WILRED MBBS
THE END
