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SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically blood pressure Blood pressure : Systolic /diastolic pressure Normal blood pressure (adults) : < 140 mm Hg/90 mm Hg Borderline HT : 140 - 160 mm Hg/90 - 95 mm Hg Definite HT : > 160 mm Hg/95 mm Hg

SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

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Page 1: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

SYSTEMIC HYPERTENSION

Hypertension (HT) = pathologically blood pressure

Blood pressure : Systolic /diastolic pressure

Normal blood pressure (adults) : < 140 mm Hg/90 mm Hg

Borderline HT : 140 - 160 mm Hg/90 - 95 mm Hg

Definite HT : > 160 mm Hg/95 mm Hg

Page 2: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

The kidney and blood pressure

• Role in regulation of blood pressure

- Renin-angiotensin system (juxtaglomerular

apparatus).

- Production of a variety of vasodepressor or

antihypertensive substances (prostaglandin, NO).

• Renal diseases may cause systemic HT.

• HT may cause renal damage.

Page 3: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :
Page 4: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Classification

Essential vs secondary HT

Benign vs malignant HT

• Essential HT

90 - 95% of cases.

Pathogenetic mechanisms multifactorial and poorly

understood.

• Secondary HT

5 - 10% of cases.

Hypertension due to a recognisable disease.

Page 5: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Diseases associated with secondary HT:

 1) Renal diseases

     - Renal parenchymal diseases (see later).

    - Renovascular HT = systemic HT due to

stenosis of a renal artery ( ischaemia

release of renin).

Page 6: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

2) Endocrine

- Adrenocortical hyperfunction/tumour (Cushing,

Conn)

- Exogenous glucocorticoids

- Pheochromocytoma

- Acromegaly

- Hyperthyroidism

- Pregnancy-induced

Page 7: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

3) Cardiovascular

- Coarctation of aorta

Page 8: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

4) Neurogenic

- Increased intracranial pressure

- Acute stress

Page 9: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Pathogenetic factors in essential HT

 Arterial blood pressure

= cardiac output (*)

x

peripheral vascular resistance (**)

Blood pressure will rise if either (*) or (**)

is increased

Page 10: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Essential hypertension is associated with:

- peripheral vascular resistance

(pathogenesis poorly understood)

- Sodium and water retention

blood volume, cardiac output

Page 11: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

A high salt intake correlates with prevalence of

essential HT.

Genetic factors:

- Sensitivity of some individuals to a high salt

intake.

  - High prevalence in blacks.

Page 12: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Benign HT

- moderate increase in blood pressure.

- long clinical course.

- little clinical effects in early stages.

Malignant HT

- diastolic pressure > 130 mm Hg

- severe impact on cardiovascular system,

kidneys and central nervous system.

Page 13: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Malignant HT:

- May arise in previously normotensive individuals, but

more commonly as a complication of benign HT.

- Relatively uncommon (1-5% of hypertensive

patients).

- Aggressive treatment is required.

Page 14: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Complications of systemic HT

Cardiovascular

CNS

Renal

Page 15: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Cardiovascular

Heart

- Increased workload on left ventricle

Left ventricular hypertrophy

left ventricular failure.

- Greater thickness of left ventricle

decreased perfusion and ischaemia of

subendocardial region of myocardium.

Page 16: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Arteries

- Accelerated atherogenesis.

- risk of developing aortic dissecting aneurism.

Arterioles: Arteriolosclerosis

- Benign HT:

Deposition of eosinophilic (‘hyaline’) material in vessel

walls due to influx of plasma proteins.

- Malignant HT:

Thickening of intima.

Necrosis of vessel walls ('fibrinoid' necrosis) and

formation of micro-aneurisms (of Bouchard) in brain.

Page 17: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

CNS

- Rupture of micro-aneurisms of small penetrating

arteries Intracerebral haemorrhage.

- Risk of cerebral infarction due to atherosclerosis

of circle of Willis.

- Acute malignant HT: ‘Hypertensive encephalopathy’

due to cerebral oedema (headache, nausea and vomiting,

visual disturbances, seizures and disturbances of

consciousness).

Page 18: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Renal complications

Arteriolosclerosis

Ischaemic sclerosis of glomeruli and

tubular atrophy.

Proteinuria and microscopic haematuria,

especially in malignant HT .

Page 19: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

VASCULITIS

Inflammation of blood vessel walls.

Types I, II, III and IV hypersensitivity reactions may contribute to the inflammation.

• Idiopathic

OR

• Associated with autoimmune diseases/

infections/drug reactions.

Page 20: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

The inflammation of the blood vessel walls may lead to:

- Thrombus formation in vessels with ischaemic

effects.

- Fragility of small vessels with petechial

haemorrages (skin and other organs).

- Weakening of vessel wall, with aneurism

formation.

Page 21: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

A. Arteritis associated with infection

Direct invasion of artery by microorganisms

(usually bacteria) in septisaemia weakening of

arterial wall mycotic aneurism, e.g. in brain.

Syphilitic aortitis

- Aneurism of aortic arch in tertiary syphilis.

- Involvement of coronary ostia myocardial

ischaemia.

- Fibrosis of valve cusps aortic insufficiency.

Page 22: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

B. Polyarteritis nodosa (PAN)

• Medium to small arteries.

• Segmental lesions.

• Immune complex disease (type III hypersensitivity

reaction).

• HbsAg + (30% of cases).

• Multisystem disease, excluding lungs .

• Ischaemic lesions.

• Renal involvement: haematuria, hypertension.

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C. Hypersensitivity (leukocytoclastic) vasculitis

Inflammation of venules, capillaries, arterioles of

skin, but also other organs.

Aetiology:

- Reactions to certain infections

- Foreign proteins ('serum sickness')

- Drugs (aspirin, penicillin, sulphonamides)

  - Auto-immune diseases

Page 24: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Henoch-Schönlein purpera

A variant of hypersensitivity vasculitis

- skin (purpera)

- abdomen (pain, vomiting, melena)

- joints (arthritis)

- kidneys (acute glomerulonephritis)

Page 25: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

D. Giant cell (temporal) arteritis

• Temporal artery and branches of external carotid

artery.

• 50 years.

• Unusual in blacks.

• Opthalmic branch of ECA blindness.

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E. Takayasu’s disease (pulseless disease)

• Young women.

• Idiopathic arteritis involving origins of branches

of aortic arch.

• Complicated by fibrosis and thrombosis

weakening of radial pulse, dizziness, syncope.

Page 27: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

E. Wegener’s granulomatosis

Granulomatous vasculitis of upper and

lower respiratory tracts, with involvement of

glomerular vessels

acute glomerulonephritis.

Page 28: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

F. Thromboangiitis obliterans (Buerger’s disease)

• Small and medium sized arteries and veins of

extremities (lower extremities in particular).

• Males < 35 years

• Cigarette smokers.

• Gangrene of fingers / toes.

• Neutrophils in vessel wall, thrombi in vessel lumen.

Page 29: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Aneurisms

Permanent, abnormal dilatation of a blood vessel due to weakening of the wall of the vessel.

Aorta and its major branches.

Less frequently: Large muscular arteries.

 

Page 30: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Complications:

• Alterations of blood flow distally

• Thrombosis and embolism

• Rupture

• Compression of adjacent structures

Page 31: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

True aneurism:

Composed of all layers of vessel.

False aneurism:

Traumatic rupture of vessel, and formation of blood-filled cavity by adventitial tissues.

Page 32: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Atherosclerotic

Syphilitic

Dissecting

Berry

Mycotic

Page 33: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Atherosclerotic aneurism:• Encroachment of atheroma on media weakening of wall.

• Most common aneurism in Western World.

• Abdominal aorta, usually infrarenal. Rarely thoracic

aorta, femoral / popliteal arteries.

• Males > 60 years.

•  Mural thrombi may embolise.

• Obliteration of branches of aorta ischaemic effects.

• Risk of rupture when > 6cm

intra-abdominal / retroperitoneal haemorrhage.

Page 34: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Syphilitic aneurism

• Complication of syphilitic aortitis (tertiary syphilis).

• > 50 years.

• Obliterative arteritis of vasa vasorum

aortitis aneurism.

• Thoracic aorta.

• Aortic valvular incompetence, cardiac failure.

• Large (15 – 20cm).

• Compression of bronchus, oesophagus.

Page 35: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Dissecting aneurism

Aetiopathogenesis:

• Degeneration of elastic and muscular tissue of the

media of thoracic aorta ('medionecrosis').

• Idiopathic.

• Some cases associated with Marfan’s syndrome or

coarctation of the aorta.

• Higher incidence in pregnancy.

• Many patients are hypertensive.

• Intimal tear blood enters the aortic wall.

Page 36: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Complications:

• Rupture:

         - into mediastinum

- into pericardial sac (cardiac tamponade)

         - back into aorta 'double-barrelled aorta'.

• Encroachment on branches of aorta (coronary, renal,

carotid arteries) with ischaemic effects.

Page 37: SYSTEMIC HYPERTENSION Hypertension (HT) = pathologically  blood pressure Blood pressure:Systolic /diastolic pressure Normal blood pressure (adults) :

Berry aneurisms

Small saccular lesions of circle of Willis.

Develop at sites of congenital weakness of media, at bifurcations of arteries.

Rupture: - Risk with hypertension.

- Subarachnoid haemorrhage .