SECONDARY HYPERTENSION

Secondary hypertension is the name given to the hypertension of which the cause is known, and can be corrected in many cases to cure the hy­pertension.

Renal hypertension :

• This is due to either renal se­retion of vasoactive compounds resulting in increased arteriolar tone or volume expansion due to distur­ance of sodium and fluid balance.
• Uncontrolled hypertension comprises the following entities:
• Secondary hypertension: Elevated blood pressure (BP) that results from an identifiable underlying mechanism Resistant hypertension: failure to achieve goal blood pressure (<140/90 mm Hg for the overall population and <130/80 mm Hg
• for those with  chronic kidney disease or diabetes when a patient adheres to maximum tolerated doses of 3 antihypertensive drugs including a diuretic” Other causes: Inadequate treatment, poor patient adherence Poor control is most often due to persistent elevation in systolic BP

Renal hypertension may be :

• Renovascular hypertension including eclampsia and reeclamsia.
• Renal parenchl’mal hypertension.
• Renal vascular hypertension is due to stenosis of main or a branch of renal artery which activates the -renin angiotensin system (RAS).
• The circulating angiotensin II causes vasoconstriction: LQ.v aldosterone secretion, sodium retention, stimulater: beren­glc nervous system a..!Jd al its direct action on:. e arterioles.
• one half of the patients there is elevation of plasma
• In activity RenaL.Parenchymal hypertension is due to in renal parenchymal disease with involvement of mulIe small renal vessels leading to decreased perfusion of renal tissue and bypertensiol
• Peripheral plasma renin activity (PRA) is normal or increased
• Cardiac output normal
• Tilting and Valsalva maneuver have no effect
• Blood volume is increased
• Cardiac output increased
• Tilting & Valsalva maneuver increase blood pressure
• Blood volume is decreased in unilateral disease

Clinical Considerations

• Pseudoresistance:
• In primary care settings, this has been estimated to occur in 40–60% of hypertensive patients.
• Poor adherence
• White-coat effect: Prevalence estimated at 20–30%
• Inaccurate measurement of BP:
• Cuff too small
• Patient not at rest; sitting quietly for 5 minutes