HYPERTENSION

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HYPERTENSION

• B.P. CONTROL
• HYPERTENSION RISK FACTORS
• EFFECTS OF HYPERTENSION
• DRUG THERAPY
• HYPERTENSION IN PREGNANCY

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REGULATION OF B.P.

• B.P. C.O. x T.P.R.
• Normal regulation maintains M.A.P. in range
  suitable for tissue perfusion
• Control - by negative feedback regulating
• a) C.O. (by S.V. and H.R.)
• b) T.P.R.

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SHORT-TERM REGULATION

• Neural and hormonal controls
• Corrects temporary imbalances (eg posture,
  exercise, bleeding)
• NEURAL
• baroreceptors C.O. ? or ?
• ANS
• CNS ischemic
• response vasoconstrict.?or?
• Note postural hypotension, shock

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SHORT-TERM REGULATION

• HORMONAL
• a) Volume regulation - by Na
• ? B.P.
• or ? vol. ?? R-A-A ? ? Na ( H2O)
• 
  vasoconstriction
• ? B.P.
• or ? vol. ? ? ANF ? ? Na ( H2O)

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SHORT-TERM REGULATION

• b) Hormonal osmolality regulation
• mainly due to ECF Na
• ?osmolality??ADH ? vasoconstr.
• ? H2O retention
• ADH vasopressin

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LONG-TERM B.P. REGULATION

• Renal mechanisms - Na and H2O regulation by
  hormones above

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HYPERTENSION

• Definition ? B.P. 140/90 in adults
• (? diastolic pressure most important)
• Normally ? with age
• Most common c.v. disorder
• Types - primary
• - secondary (5-10 )
• Basic defect ? tendency for arteriole smooth
  muscle contraction
• Signs and symptoms none

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HYPERTENSION RISK FACTORS

• Family history (genetic
• predisposition)
• ? age
• ? salt intake for some people
• Lifestyle
• - obesity ( hyperinsulinemia)
• - smoking
• - alcohol (? systolic)

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EFFECTS OF UNTREATED HYPERTENSION

• ? wear and tear in blood vessels
• ? hemorrhagic stroke
• ? aneurism
• ? atherosclerosis
• In heart
• ? work for L. ventricle ? hypertrophy
• Renal sclerosis of arterioles
• (? ? nephrons, ? renin etc)
• In retina hemorrhages ? retinopathy

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TREATMENT OF HYPERTENSION

• Goal ? B.P. lt 140/90 mm Hg
• Treatment
• Secondary - correct the cause
• (eg kidney disease)
• Primary (essential hypertension)
• a) Lifestyle modification (? risk factors)
  then..
• b) Pharmacological selection

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ANTIHYPERTENSIVE DRUGS

• A. One of the following at first
• Thiazide diuretic (? Na)
• ?-blocker (to ? H.R. and renin)
• ACE inhibitor (to ? angiotensin II)
• Arteriolar vasodilation (Ca2 channel antagonists
  eg nifedipine)
• ?-adrenoceptor block (? T.P.R.)
• B. Combination of above (lower dose)
• eg diuretic with ?-blocker or ACE inhib

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ANTIHYPERTENSIVE DRUGS

• Problems with treatment
• - absence of symptoms, slow progress of disease,
  side-effects, medication for life
• - noncompliance is a major cause of hypertension
  treatment failure

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HYPERTENSION IN PREGNANCY

• Normal pregnancy
• ? B.P. in 1st, 2nd trimesters but
• blood volume is ?, and C.O. is?
• ? T.P.R. is ? (vasodilation)
• Hypertension in pregnancy (10)
• - may be pregnancy-induced ( proteinuria, edema
  preeclampsia)
• - abnormal placental flow, mediators
• - life-threatening ? pre-term birth