A Quick Literature Review Presentation on: Hypertension Presentation - PDF document

See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/297880469 A Quick Literature Review Presentation on: Hypertension Presentation · January 2012 DOI: 10.13140/RG.2.1.3450.5361 CITATIONS READS 0 2,564 1 author: Teketel Eristu Kediso Addis Ababa University 3 PUBLICATIONS 0 CITATIONS SEE PROFILE All content following this page was uploaded by Teketel Eristu Kediso on 12 March 2016. The user has requested enhancement of the downloaded file.

College of Health Sciences Department of Medical Physiology Advanced Cardiovascular Physiology Presentation on Hypertension By Teketel Eristu 1

Presentation Outline  Introduction  Blood Pressure  High Blood Pressure/Hypertension  Causes of Hypertension/Risk Factors  Types of Hypertension  Regulation of HBP/HPN  Prevention and Treatment of HPN  Animation of HPN, Video  References 2

Objectives At the end of the Presentation the Learners are expected to: Discuss about Blood Pressure Explain High Blood Pressure/ Hypertension in detail Classify Hypertension and Causes Explain the Consequences of Hypertension Discuss the regulation of Hypertension Explain Treatment of Hypertension 3

1. Introduction Blood Pressure - is the pressure exerted by circulating blood upon the walls of blood Vessels -decreases as the circulating blood moves away from the heart - expressed in terms of the systolic pressure over diastolic pressure (mmHg). Or it makes Lup Dup major sound 4

Dub Lub If you listen to your heartbeat, it makes a lub dub sound. The lub is when blood is pushed out of the heart into the body and the dub is the reloading of the heart with more blood ready to push it out to the body 5

Cont.. Blood pressure is an important characteristic of our body. Without blood pressure, nutrients, oxygen, and proteins could not travel from the arterial side of the body to the venous side. 6

Cont … Normal Blood Pressure 95/65 mmHg=1 Years 100/65 mmHg=6-9 years 110/65-140/90mmHg= Adults -its Average Physiologic Value (normal BP) = 120/80 mmHg 7

Cont… If blood pressure is chronically elevated a condition is known as hypertension According to medical dictionary, hypertension means "High blood pressure; transitory or sustained elevation of systemic arterial blood pressure A consistent blood pressure of 140/90 mm Hg or higher is considered high blood pressure. 8

Cont … • Isolated Systolic Hypertension is Systolic BP elevation in the absence of elevated diastolic Blood Pressure . • Isolated Diastolic Blood Pressure is Diastolic BP elevation in the absence of Systolic BP. • Accelerated Hypertension / Malignant Hypertension occurs when BP elevates extremely . 9

Table.1. Classification of Blood Pressure for Adults =>18 Years old Category Systolic mmHg Diastolic mmHg Hypotension <90 <60 Desirable/Normal 90-119 60-79 Prehypertension 120-139 80-89 Stage 1/Mild Hypertension 140-159 90-99 Stage 2 / Moderate 160-179 100-109 Hypertension Hypertensive Crisis/ stage 3/ => 180 =>110 Severe/HYN 10 Isolated Systolic HYN =>140 <90

2. Types of Hypertension is abnormal elevation of pulmonary artery BP. 11

Cont… • Pulmonary blood pressure is normally a lot lower than systemic blood pressure. • Normal pulmonary-artery pressure is about 14 mm Hg at rest. • If the pressure in the pulmonary artery is greater than 25 mm Hg at rest and 30 mm Hg during exercise, it is abnormally high and is called pulmonary hypertension. • Broadly Classified as Primary or Secondary Hypertension 12

Cont… • Primary pulmonary hypertension • When not accompanied by underlying heart and lung disease or other illnesses, it is called primary pulmonary hypertension. 13

Con…. Secondary pulmonary hypertension If a pre-existing disease triggered the PHT e.g . Congenital heart defects Intracardiac left-to-right shunts : Heart valve conditions : mitral stenosis 14

Cont…. • Typically "blood pressure," "high blood pressure" and "hypertension" refer to the systemic pressure throughout your body. Hypertension is classified as either primary (essential) Idiopathic / hypertension or secondary hypertension 15

a) Primary or Essential Hypertension About 90–95% of cases are categorized as "primary hypertension," which means high blood pressure with no obvious/direct medical cause. -is the most prevalent hypertension type 16

Cont .. Although no direct cause has been identified, there are many factors such as sedentary lifestyle, smoking, stress, visceral obesity,, salt (sodium) sensitivity, alcohol intake, and vitamin D deficiency, aging, some inherited genetic mutations and having a family history of hypertension, an elevated level of renin, sympathetic nervous system over activity…etc. increase the risk of developing primary hypertension. 17

b) Secondary Hypertension About 5–10% of cases (Secondary hypertension) are caused by other conditions that affect the kidneys, arteries, heart or endocrine system. Thus, results from an identifiable cause . but: may come to normal values by treatment. 18

Cont … This type is important to recognize since it's treated differently to essential hypertension. Facrors that cause this type of HYN 1. Adrenocortical hyperfunction Primary hyperaldosteronism Cushing Syndrome Congenital or hereditary adrenogenital syndromes (17a-hydroxylase and 11b-hydroxylase defects) 2. Pheochromocytoma 3. Severe Polycythemia 19

Cont… 4). Renal Diseases It is common for all types of chronic kidney disease to eventually cause hypertension (approx. 80% of chronic kidney disease patients develop hypertension at some point). This is due to fluid retention in the body, due to poor elimination of fluids and poor control of sodium 20

Cont…. Glomerulonephritis (chronic renal inflammation ) Polycystic renal disease-is cystic genetic disorder of the kidneys Tumors of JG Cell- Renin-producing tumors Renovascular stenosis or renal infarction (Reno vascular hypertension)------RAS Hyperparathyroidism and Calcium overload leads to renal failure and hypertension 21

Cont… 5 ) Neurogenic hypertension Polyneuritis ( lead poisoning…..) inflammation of Peripheral nerves Increased intracranial pressure Arterial occlusion Tumors 22

Cont …. Others Coarctation of aorta  BP in upper parts of body, i.e. above obstruction. Hypercalcemia Medications, e.g., glucocorticoids, …etc 23

Consequences of Hypertension: Organ Damage Hypertension Hypertension Transient ischemic LVH, CHD, CHF LVH, CHD, CHF attack, stroke Peripheral arterial Retinopathy Retinopathy Chronic kidney disease disease CHF=congestive heart failure; CHD=coronary heart disease; LVH=left ventricular hypertrophy. 24 Chobanian AV et al. JAMA. 2003;289:2560-2572.

Regulation of HBP/HPN Introduction: Blood Pressure is regulated within a narrow Range If the blood pressure is too low: Inadequate perfusion of organs If the Blood pressure is abnormally high: Heart diseases, Vascular diseases ,strokes…. 25

Cont … The Baroreceptor reflex functions to restore blood pressure back to normal values whenever the blood pressure deviates from the normal range. The homeostatic mechanism involves a negative feedback loop to minimize and oppose any changes in Blood pressure. i.e. An increase in BP reflexively causes the BP to decrease and vice versa. 26

What is a Baroreceptor? High pressure baroreceptors respond to stretch in the aortic arch and carotid sinus. Stretch –sensitive Mechanoreceptors Located in the Carotid Sinus and aortic arch Monitor the pressure of blood flow to brain and body Action potentials are fired continuously at normal Fig. 1 Location and innervations of arterial Baroreceptor blood pressure 27

Pathway Increase in BP stretches the baroreceptors and increase the firing rate in the afferent nerves Glossopharyngeal nerve and Vagus nerve This leads to the excitation of the nucleus tractus solitarius(NTS) in the Medulla, which inturn inhibits the vasomotor center via interneurones. 28

Cont… The inhibition of the vasomotor center decrease the sympathetic output and causes vasodilation, bradycardia, decrease in CO & fall in BP The excitation of NTS also stimulates the Vagus nerve which decrease the HR & CO 29

Baroceptors Carotid Aortic arch sinus baroceptors with increased P baroceptors + + Carotid sinus nerve Carotid sinus nerve Vagus nerve Vagus nerve glossopharyngeal nerve glossopharyngeal nerve Medulla Nucleus tractus solitarius + - Cardiac Cardiac Cardiac Vaso decelerator accelerator accelerator constrictor Dilation Sinoatrial Sinoatrial Contract- Contract- Arterioles Arterioles Veins Veins Heart and Blood Vessels node node ility ility - - Heart Blood vessels 30

Blood Pressure Regulation • Main coordinating center is in the medulla oblongata of the brain; medullary cardiovascular control center Baroreceptors Afferent nerves Medulla oblongata center Sympathetic efferents SA node, ventricles, Arteriolar smooth muscle Venous smooth muscle Fig 2 Components of the Baroreceptor Reflex 31

Regulation of Blood Pressure 32 Figure 3 T he baroreceptor reflex: the response to increased blood pressure