Essential hypertension

Essential Hypertension Pathology Lecture

1. ESSENTIAL HYPERTENSION

2. Outline Definition Etiology Pathogenesis Clinical features Diagnosis Complications Treatment

3. Definition Sustained elevation of blood pressure Systolic blood pressure  140 mm Hg Diastolic blood pressure  90 mm Hg

4. Peripheral resistance is determined by: the calibre total cross-sectional area of the resistance vessels (small arteries and arterioles ). Factors that increase cardiac output or peripheral resistance therefore increase blood pressure.

5. Types of hypertension Primary (Essential) accounts for 95% cases of HTN. no universally established cause known . Secondary less common cause of HTN ( 5%). secondary to other potentially rectifiable causes.

6. Clinical forms of hypertension Benign Systole <200mmHg Diastole <120mmHg Hyaline arteriosclerosis Malignant Systole >200mmHg Diastole >120mmHg Hyperplastic arteriosclerosis

7. Etiology Essential hypertension Multifactorial disease. Unknown specific etiology and pathogenesis .

8. Predisposing factors Modifiable stress obesity High salt intake lack of Mg 2+ , K + ethanol  dose smoking Non-modifiable positive family history insulin resistance Age Sex defect of local vasomotor regulation

9. Pathogenesis Specific mechanisms unknown. Proposed mechanisms: Genetic factors Reduced sodium excretion Environmental factors Increased vascular resistance

10. Mechanisms of essential hypertension Genetic factors This is evidenced by: Familial aggregation Occurrence of hypertension in twins Identification of hypertension susceptible gene (angiotensinogen gene)

11. Mechanisms of essential hypertension Reduced sodium excretion The kidney plays a key role in long-term control of blood pressure excretion of salt and water controls intravascular volume.

12. Mechanisms of essential hypertension Gene defects in enzymes involved in aldosterone metabolism such as: aldosterone synthase 11 beta-hydroxylase 17 alpha-hydroxylase lead to increased aldosterone secretion. This leads to increased sodium and water retention hence increased plasma volume and blood pressure.

13. Mechanisms of essential hypertension

14. Complications Mutations in genes encoding ENaC . Increased distal tubular reabsorption of sodium induced by aldosterone.

15. Mechanisms of essential hypertension Environmental factors such as stress ,obesity and smoking modify the impact of genetic determinants thus leading to hypertension . Increased vascular resistance .- due to vasoconstriction of small arteries and arterioles or structural changes in vessel wall

16. Clinical manifestations Frequently asymptomatic until severe and target organ disease has occurred Fatigue, reduced activity tolerance Dizziness Palpitations, angina Dyspnea

17. Complications Cerebrovascular disease Stroke Retinal Damage Hypertensive heart disease Nephrosclerosis

18. Complications

19. Complications Normal Retina Hypertensive Retinopathy

20. Complications Hypertensive heart disease

21. Treatment Lifestyle modification - Weight reduction Dietary changes Sodium restriction Limitation of alcohol intake Regular physical activity Avoidance of tobacco use Stress management Antihypertensive drugs Diuretics Adrenergic inhibitors β - Adrenergic blockers ACE Inhibitors Calcium channel blockers

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