Pathology of Hypertension:

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Pathology of Hypertension

• Dr. Venkatesh M. Shashidhar.
• Senior Lecturer in Pathology
• Fiji School of Medicine

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Hypertension - Introduction

• Silent Killer painless complications
• dizziness, headache, and visual difficulties,
• It is the leading risk factor MI, DM, Stroke
• Responsible for the majority of office visits,
• Number one reason for drug prescription.
• 25 of population, lt35 aware. lt5 ..!
• Complications bring to diagnosis but late
• Chronic, vascular end organ damage.

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Introduction

• Sustained increase in blood pressure
• Systolic gt140, Diastolic gt 90 mm of Hg
• Normal lt 130 lt85 (120/80 /- 10/5)
• Mild 20, Moderate 40 Severe 80
• Malignant - gt 210/120

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Regulation of BP

• BP Cardiac Output x Peripheral Resistance
• Endocrine Factors
• Renin, Angiotensin, ANP, ADH, Aldosterone.
• Neural Factors
• Sympathetic Parasympathetic
• Blood Volume
• Sodium, Mineralocorticoids, ANP
• Cardiac Factors
• Heart rate Contractility.

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Control of Blood Pressure
Humoral Factors
Vasoconstrictors Angiotensin II Catecholamines
Vasodilators Pg Kinins
Blood Volume Na, Aldosterone
Cardiac Factors Rate Contract..
Local Factors pH, Hypoxia

• Neural Factors
• Adrenergic Cons
• ß Adrenergic - Dil

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Etiologic Classification

• Primary or Essential Hypertension(95)
• Secondary Hypertension (5-10)
• Renal GN, RAS, Renin tumors
• Endocrine Cushing, OCP, Thyrotoxicosis Myxdema,
  Pheochromocytoma, Acromegaly.
• Vascular Coarctation of Aorta, PAN, Aortic
  insufficiency.
• Neurogenic Psychogenic, Intracranial pressure,
  olyneuritis etc.

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Pathogenesis of Hypertension

• ? Pathogenesis in Essential hypertension -
  Multifactorial
• Increased blood volume - Sodum retention ADH,
  Aldosterone.
• Increased sympathetic tone - Adrenal tumours,
  sympathetic stimulation.
• Increased vasoactive hormones - Cushings,
  Pheochromocytoma,

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Pathogenesis of Renovascular HTN
?GFR
Renin by JGA
Angiotensin II
Aldosterone
Vasoconstriction ? P. Resistance
Sodium Retention ?Blood Volume
Hypertension
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Consequences of Hypertension

• Blood Vessels
• Atherosclerosis and its complications aneurism,
  Dissection, Rupture, necrosis. Arteriolosclerosis,
  
• Heart
• Hypertensive cardiomyopathy, IHD, MI.
• Kidney
• Benign/Malignant nephrosclerosis. Infarction
• Eyes
• Hypertensive retinopathy
• Brain
• Haemorrhage, infarction,
• splinter Lacunar hemorrhages

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Hyperplastic Arteriolosclerosis
Narrow Lumen
Onion Skin Thickening Of arterioles.
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Benign Nephrosclerosis
Leathery Granularity due to minute scarring
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Left Ventricular Hypertrophy
Left Ventricular Hypertrophy
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Cerebral Infarction (Stroke)
Haemorrhagic Necrosis
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Subarachnoid Haemorrhage

• Cerebral Blood vessels
• Special features
• Thin walled
• End arteries
• Cong. Aneurisms

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Lacunar Infarcts

• Chronic hypertension
• Arteriolosclerosis of deep penetrating arterioles
  of brain stem.
• Single or multiple cavitary infarcts lacunes.
• Lenticular nucleus, thalamus
• Slit Haemorrhages.

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Renal Artery stenosis - Atrophy
Leathery Granularity Benign Nephrosclerosis
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Normal Retina - Fundoscopy
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Hypertensive Retinopathy

• Grade I Thickening of arterioles.
• Grade II Focal Arteriolar spasms. Vein
  constriction.
• Grade III Hemorrhages (Flame shape), dot-blot
  and Cotton wool and hard waxy exudates.
• Grade IV - Papilloedema

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Malignant Hypertension

• May complicate any type of HTN.
• Necrotizing arteriolitis.
• Intravascular thrombosis.
• Rapidly progressive end organ damage.
• Renal failure
• Hypertensive encephalopathy.
• Left ventricular failure.

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Necrotizing arteriolitis
Thrombosis
Fibrinoid Necrosis
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Conclusions

• Persistent increased blood pressure (140/90)
• 95 Essential, 5 secondary - Renovascular
• Benign and Malignant types (gt120Diastolic)
• Vessel damage Arteriolosclerosis
• Complicates - Atherosclerosis, Diabetes, IHD
• Ischemia or Infarction in end organs.
• Kidney, Brain, Heart Eyes.
• Nephrosclerosis, renal damage, IHD, MI, Stroke
  Retinopathy.

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Self Assessment Questions

• Define essential, hypertension?
• Briefly describe pathogenesis of renal damage in
  hypertension.
• Classify hypertension, briefly describe
  pathogenesis in each?
• Summarize common complications of hptn?
• What is nephrosclerosis? Briefly describe its
  pathogenesis?
• What is meant by malignant hypertension? Briefly
  describe clinical and pathological features?
• What are lacunar infarcts? arteriolosclerosis?
• How does hptn causes stroke? Damage heart?

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