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HYPERTENSION Pathophysiology

HYPERTENSION Pathophysiology. Dr. Zahoor Ali Shaikh. Hypertension. 1. Essential hypertension (90-95%) 2. Secondary hypertension (5-10%). Hypertension. We will discuss pathophysiology of essential Hypertension . Although no cause is identified but

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HYPERTENSION Pathophysiology

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  1. HYPERTENSIONPathophysiology Dr. Zahoor Ali Shaikh

  2. Hypertension 1. Essential hypertension (90-95%) 2. Secondary hypertension (5-10%)

  3. Hypertension • We will discuss pathophysiology of essential Hypertension. • Although no cause is identified but 1. constitutional or inherent factors 2. life style or environmental factors have been implicated.

  4. Essential Hypertension 1. Constitutional factors • Inborn risk factors or constitutional factors • Genetic factors e.g. liddles syndrome • Family H/O hypertension • Fetal factors • Race Black people are more prone to high blood pressure. • Age related increase in blood pressure • Insulin resistance

  5. Liddles syndrome • Autosomal dominant - Genetic mutation at locus 16p13-p12 causing dysregulation of epithelial sodium channel (ENaCl) • There is hypertension with low plasma rennin and aldosterone and decrease potassium. • There is abnormal kidney function with increased reabsorption of sodium and loss of potassium from renal tubule.

  6. Family H/O hypertension • BP runs in families. • Children of hypertensive parents have higher BP than children of normotensive parents. Fetal factor • Babies born with low birth weight get high BP.

  7. Insulin resistance • It leads to hypertension, prediabetes, typeII diabetes, hyper lipidemia and obesity • It is called insulin resistance or Metabolic syndrome.

  8. 2.Life style risk factors • Can contribute to the development of hypertension • Increase salt intake – causes increase blood volume, increase cardiac output, increase peripheral resistance • Increase alcohol consumption – systolic BP is affected more. • Stress – increase sympathetic activity

  9. Life style risk factors [cont] • Obesity – lepton hormone derived from adipose tissue, causes increase sympathetic activity via hypothalamus • There is research, supporting activation of renin-angiotensin-aldosterone system by adipocyte derived angiotensinogen. • Smoking

  10. We will discussSecondary hypertension • It is increase in blood pressure due to another disease condition. • Occurs in 5-10% cases • Causes • Renal disease • Glomerulonephritis • Chronic pyelonephritis, • Polycystic kidney disease • Diabetic nephropathy • Renal artery stenosis

  11. Secondary hypertension [cont] • Renal hypertension occurs due to decreased renal blood flow – increase renin – activation of renin- angiotensin -aldosterone mechanism • Endocrine causes • Adrenal cortical disorder • Primary hyper aldosteronism or Conn's syndrome due to adenoma of renal cortex • Cushing’s syndrome

  12. Secondary hypertension Endocrine cause (cont) • Pheochromocytoma – tumor of adrenal medulla - There is paroxysmal hypertension, headache excessive sweating and palpitation – due to paroxysmal release of catecholamine (50% cases). - Other patients of Pheochromocytoma may have sustained hypertension (50%cases)

  13. Secondary hypertension [cont]CVS causes • Coarctation of aorta • Narrowing of aorta in adult usually occurs just distal to origin of subclavian arteries • Large stroke volume is ejected into narrowed aorta which results in increase in systolic BP in upper parts of the body

  14. Secondary hypertension Coarctation of aorta (cont) • BP in lower extremities may be normal or low • Femoral pulses are weak • Blood pressure in arms if 20 mm of Hg or higher than in legs is suggestive of Coarctation of aorta • Respiratory cause of secondary Hypertension • Obstructive sleep apnea

  15. Drugs • Oral contraceptives – Estrogen & progesterone in contraceptive pills causes Na+ retention • common cause of secondary HT in young women • Women should check their blood pressure regularly when they are taking the pill • Steroids, Vasopressin • Cocaine • Amphetamine • Erythropoietin

  16. Complications of hypertension • Target Organ damage occurs due to long term effect of hypertension • Organs affected are • Heart • Eyes • Kidney • Blood vessels – increase risk of coronary artery disease and stroke

  17. Hypertensive crises • Situation when markedly increased blood pressure is accompanied by progressive target organ damage • It is defined as diastolic BP greater than 120 mmHg • Goal of initial treatment is partial reduction of BP to safe level, rather than to normal level

  18. Malignant hypertension – when BP rises rapidly, diastolic BP more than 130mmHg. Unless treated, it may lead to death due to renal failure, heart failure or stroke. • Severe hypertension is defined when blood pressure is more than 180/110 mmHg • If diastolic blood pressure is more than 110 mmHg it should be treated urgently

  19. Hypertension in special population • High BP in pregnancy • Hypertension may complicate 5-10% of pregnancies • Causes may be • Pre-eclamsia • Eclampsia • Gastational hypertension • Chronic hypertension

  20. High BP in pregnancy • Pre-eclampsia • There is new onset of hypertension with proteinuria • Develops in last half of the pregnancy(after 20 wks) of pregnancy • BP is more than 140 / 90 mmHg • Cause:Decreased placental blood flow – release of toxins which act on blood vessles

  21. IMPORTANT • Blood pressure in pregnancy should be treated with safe anti hypertensive drugs, e.g.. Methyl dopa • ACE inhibitors can cause injury or even death of fetus when given during second or third semester of pregnancy

  22. High BP in children and adolescents • In children BP occurs in 1-3% • Reports are, BP is increasing in children • WHY??? • Because of obesity, decrease physical activity, increase uptake of salt and high caloric diet

  23. High BP in elderly • BP increases with age • 50% of people may be affected between 60 – 69 yrs. • Cause • Atherosclerosis – stiff large artery • Increase peripheral resistance • Decrease renal blood flow

  24. Orthostatic Hypotension or Postural hypotension • It is abnormal drop of BP on standing • Systolic BP drops more than 20 mmHg and diastolic BP drops more than 10 mm Hg • Person will feel dizziness and syncope • Take BP supine and standing position

  25. Causes of orthostatic/postural hypotension • Decrease blood volume e.g.. bleeding peptic ulcer, gastroenteritis, diuretics • Drugs e.g.. Vasodilators • Ageing • Autonomic nervous system dysfunction • Peripheral neuropathy in diabetes mellitus • Stroke • Parkinsonism with ANS failure

  26. THANK YOU

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