hypertension -definition, etiology and mechanism

Information about hypertension -definition, etiology and mechanism

Published on July 31, 2014

Author: toufiqurrahman52

Source: authorstream.com

Content

Hypertension –Definitions and Mechanisms: Hypertension –Definitions and Mechanisms Dr. Md.Toufiqur Rahman MBBS, FCPS , MD, FACC , FESC, FRCPE , FSCAI, FAPSC, FAPSIC , FAHA, FCCP, FRCPG Associate Professor of Cardiology National Institute of Cardiovascular Diseases, Sher -e- Bangla Nagar, Dhaka-1207 Consultant, Medinova , Malibagh branch Honorary Consultant, Apollo Hospitals, Dhaka and STS Life Care Centre, Dhanmondi [email protected] Definition: Definition Blood pressure (BP) in human populations has a normal  distribution.  Accordingly,the  definitions of "normal" BP and of various forms of  hypertension are arbitrary, but are needed for practical reasons in the assessment and  treatment of patients. Hypertension is defined as a systolic blood pressure (SBP) of 140 mm Hg or greater and/or a diastolic blood pressure (DBP) of 90 mm Hg or greater in persons not taking antihypertensive medication [email protected] Pre Hypertension: Pre Hypertension Those with a BP of 120­139 mm Hg systolic and/or 80­89 mm Hg diastolic  areclassified  as " prehypertensive ," now known to increase the risk of any CV event  bytwo ­ to fourfold compared with a normal BP (<120/80 mm Hg). [email protected] Isolated systolic hypertension: Isolated systolic hypertension Ageing is associated with a progressive increase in  systolic BP, a reduction  indiastolic  BP, and widening of the pulse pressure. This is a reflection of a progressive reduction in the compliance, or stiffening, of large conduit arteries. "Isolated systolic hypertension" (ISH), the predominant form of hypertension in  theelderly , is defined as a  SBP of 140 mm Hg or greater in the presence of a  DBP of 90mm Hg or lower. [email protected] Essential, primary, or idiopathic hypertension: Essential, primary, or idiopathic hypertension "Essential, primary, or idiopathic hypertension," defined as high BP due neither  tosecondary  causes  nor  to a  Mendelian  (monogenetic) disorder, accounts for 90% of all cases.  The term "primary hypertension" is preferred, since “ essentialhypertension " represents an archaic  misunderstanding of  pathophysiology , namely that hypertension is "essential" to maintain blood flow through severely narrowed resistance vessels. [email protected] Secondary hypertension: Secondary hypertension "Secondary hypertension " is high BP caused by an identifiable and  potentiallycurable  disorder.  "Refractory or resistant hypertension" is defined as a  BP of≥140/90 mm Hg despite three drugs of different classes at  maximum approved doses, given for at least 1 month.  " Spurious hypertension ( pseudohypertension )" is artefactually  elevated BP obtained by indirect cuff  measurement over a rigid,  oftencalcified , brachial  artery. [email protected] White­coat hypertension: White­coat  hypertension " White­coat  hypertension" describes patients whose BP is  high (>140/90 mm Hg)  i na n  office or clinic setting,  with a  normal daytime ambulatory pressure (<135/85  mmHg).  This is a relatively benign condition with low risk of morbid  events; however, the risk may  increase with  long­term   follow­up  (6 years or more). Antihypertensivemedication  in  white­coat  hypertension  patients may decrease clinic BP, but produces little or no change in ambulatory BP; thus, drug  treatment may not confer substantial benefit.   Masked hypertension: Masked hypertension " Masked hypertension " is the mirror image of  white­coat  hypertension.  Here,  th ec linic  BP is normal, but ambulatory or home measurements are high,  an da ssociated  with high risk. Although the prevalence of masked  hypertension is low, perhaps only 6% of the  normotensive  population,  the absolute number in the United States may approach 15­18 million. Hypertensive crisis: Hypertensive crisis " hypertensive crisis " encompasses both hypertensive urgency  an dh ypertensive  emergency.  "Hypertensive urgency" is defined as DBP >120 mm Hg  i nt he  absence of acute or rapidly worsening  target­organ  damage. Hypertensive emergency: Hypertensive emergency "Hypertensive emergency " is defined as acute or rapidly worsening  target­orga nd amage  occurring in a  hypertensive patient in association with elevated BP,  bu t i rrespective of the specific BP level attained.  " Malignant hypertension " is  ah ypertensive  emergency  associated with  papilledema , whereas  " accelerate dh ypertension " is a hypertensive emergency associated with retinal hemorrhage s a nd exudates. PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] PowerPoint Presentation: [email protected] Summary: Summary Hypertension is very common in nearly all populations, and is a major independent risk factor for CVD. There is a graded relationship between BP and CV risk, with no apparent lower limit. BP targets are <130/80 mm Hg for those with diabetes, kidney disease, and coronary artery disease. The etiology of hypertension is  multifactorial ;  monogenetic forms are rare.  [email protected] Summary: Summary Key elements in the etiology  ar e activation  of  neurohormonal  systems (sympathetic nervous system, RAAS, ET);  increased oxidative stress; altered cellular ion transport of sodium, potassium, and calcium; and abnormalities of endothelial function and vascular reactivity, large artery compliance, and small artery/ arteriolar resistance. The main  target­organ  effects and resultant CVD events are  atherosclerotic vascular disease; MI, LV hypertrophy, atrial  fibrillation, heart failure; stroke, encephalopathy,  dementia, and renal failure. [email protected] PowerPoint Presentation: Thank you ! [email protected]

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