L2 Pathophysiology

Hypertension

Failure of BP control/compensatory mechanisms

Consistently elevated BP

E.g. baroreceptors adapt or “reset” to operate at higher levels

What are potential causes of primary hypertension (5)?

• excessive salt intake

• Defects in salt management by kidneys

• Excess vasopressin

• Abnormalities in NO or endothelin

How does excessive salt intake cause primary hypertension?

osmotically retains water

Increases plasma volume = ↑ blood pressure

How does defects in salt management in kidneys cause primary hypertension?

accumulation of salt and H2O

How does excess vasopressin cause primary hypertension?

Causes vasoconstriction

Also promotes H2O retention

How does abnormalities in NO or endothelin cause primary hypertension?

NO - vasodilator (not enough)

Endothelin - vasoconstrictor (too much)

Causes of (secondary) hypertension

-

How does pheochromocytoma cause secondary hypertension?

Secretes excess adrenaline and noradrenaline

Abnormal levels ↑ CO and peripheral vasoconstriction

Defect in cardiovascular control centre causes increase in BP

-

Medicines used for hypertension

A, B, C, D, E

A stands for..

• ACE inhibitors (perindopril)

• Ang II receptor antagonists (candesartan)

• a-adrenoceptor antagonists (prazosin)

B stands for..

B-adrenoceptor antagonists/B-blockers (metoprolol)

C stands for..

Calcium entry antagonists/blockers (nifedipine, verapamil)

D stands for..

Diuretics (dihydrochlorothiazide)

E stands for..

Endothelin antagonists (bosentan)

Endopeptidase inhibitors (omapatrilat)

MECHANISMS, SIDE EFFECTS OF MEDS

REFER TO COLLANOTE