Hypertension

Robbins: 525 to 530, 1007-1009Cecil: 167-173

Hypertensive Vascular Disease

• HTN risk factor for:• Coronary heart disease• Stroke• LVH with heart failure• Aortic dissection• Renal failure

Hypertension• Sustained:

• Diastolic > 90 (some >80)• Systolic > 140

• See table 13-8 in Cecil Essentials

Normal <120 And <80

Prehypertension 120-139

Or 80-89

Stage 1 140-159

Or 80-90

Stage 2 >160 Or >100

Causes of Hypertension

• 90-95% idiopathic• 5-10% 2° to renal disease or

renovascular hypertension• All other causes rare

Accelerated (Malignant) hypertension

• Severe hypertension (diastolic >120mmHg)

• Renal failure• Retinal hemorrhages with papilledema• Seizures • Strokes• DIC

Normal Blood Pressure

• Cardiac output• Na homeostasis

• Total peripheral resistance• Lumen size• Neural and hormonal influences that

constrict or dilate these vessels

Kidney

• Renin-produced by the JG cells of the kidney

• Transforms plasma angiotensinogen to angiotensin I

• Angiotensin I converted to angiotensin II by ACE

• Angiotensin II increases peripheral resistance and blood volume

The Kidney Produces Vasodepressor Substances

• Prostaglandins• Kallikrein-kinin• Platelet-activation factor• Nitric oxide

Blood volume reduced

• Glomerular filtration rate falls• Increased reabsorption of Na• Leads to conserve Na and expand blood

volume

GFR-independent Natruretic Factors

• Atrial natriuretic factor (ANF)• Inhibits Na reabsorpton in distal tubules• Cause vasodilatation

Essential hypertension

• Alter the relationship between volume and total peripheral resistance

Renovascular hypertension

• Renal artery stenosis causes deceased glomerular flow

• Induces renin secretion• Induces angiotensin II-induced

vasoconstriction• Increased peripheral resistance• Aldosterone causes increased sodium

reabsorption and inceased blood volume

Genetic factors

• Environmental factors• Salt, stress, smoking• Obesity, physical inactivity

Mechanisms

• Renal retention of excess sodium• Vasoconstriction and vascular

hypertrophy• Thickened wall• Narrowed lumen

Vascular pathology

• Hyaline Arteriolosclerosis• Hyalinized walls with narrowed lumen

• Hyperplastic arteriosclerosis• Concentric, laminated thickening of wall

(onion-skin)• Progressive narrowing of the lemen

• Necrotizing arteriolitis-fibroid necrosis

Hyaline arteriosclerosis

Hyperplastic arteriosclerosis - malignant hypertension

Hyperplastic arteriosclerosis - malignant hypertension