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  ICD10 I10-I15
  ICD9


Hypertension or '''high blood pressure''' is a medical condition wherein the Blood Pressure is chronically elevated. While it is formally called '''arterial hypertension''', the word "hypertension" without a qualifier usually refers to Arterial hypertension.

Persistent hypertension is one of the risk factors for Stroke s, Heart Attacks , Heart Failure and arterial Aneurysm , and is a leading cause of Chronic Renal Failure .


DEFINITION

Blood pressure is a continuously distributed variable, and the risk of associated cardiovascular disease likewise rises continuously. The point at which blood pressure is defined as hypertension is therefore somewhat arbitrary. Presently finding sustained Blood Pressure of 140/90 MmHg or above, measured on both arms is generally regarded as diagnostic. Because blood pressure readings in many individuals are highly variable — especially in the office setting — the diagnosis of hypertension should be made only after noting a mean elevation on two or more readings on two or more office visits, unless the elevations are severe or associated with compelling indications such as Diabetes Mellitus , chronic kidney disease, Heart Failure , post-myocardial infarction, stroke, and high coronary disease risk.

  url http://jamaama-assnorg/cgi/content/full/289192560v1
  author Chobanian AV et al
  journal JAMA
  title The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report
  year 2003
  volume 289
  pages 2560-72
  id PMID 12748199


In patients with Diabetes Mellitus or Kidney disease studies have shown that blood pressure over 130/80 mmHg should be considered a risk factor and may warrant treatment.


ETIOLOGY




PATHOPHYSIOLOGY

The mechanisms behind the factors associated with inessential hypertension are generally fully understood, and are outlined at Secondary Hypertension . However, those associated with essential hypertension are far less understood. What is known is that Cardiac Output is raised early in the disease course, with Total Peripheral Resistance normal; over time cardiac output drops to normal levels but TPR is increased. Three theories have been proposed to explain this:


SIGNS AND SYMPTOMS

Hypertension is usually found incidentally - "case finding" - by healthcare professionals. It normally produces no symptoms.

Malignant Hypertension (or accelerated hypertension) is distinct as a late phase in the condition, and may present with headaches, blurred vision and end-organ damage.

It is recognised that stressful situations can increase the blood pressure; if a normally normotensive patient has a high blood pressure only when being reviewed by a healthcare professional, this is colloquially termed ''white coat effect''. Since most of what we know of hypertension and its outcome with or without modification is based on large series of readings in doctors' offices and clinics (e.g., Framingham), it is difficult to be sure that white-coat hypertension is not significant. Ambulatory monitoring may help determine whether traffic and ticket inspectors produce similar sustained rises.

Hypertension is often confused with mental tension, stress and anxiety. While chronic anxiety is associated with poor outcomes in people with hypertension, it alone does not cause it.


Hypertensive urgencies and emergencies

Hypertension is rarely severe enough to cause symptoms. These only surface with a Systolic Blood Pressure over 240 mmHg and/or a Diastolic Blood Pressure over 120 mmHg. These pressures without signs of end-organ damage (such as renal failure) are termed "accelerated" hypertension. When end-organ damage is possible or already ongoing, but in absence of raised Intracranial Pressure , it is called Hypertensive Emergency . Hypertension under this circumstance needs to be controlled, but prolonged hospitalization is not necessarily required. When hypertension causes increased intracranial pressure, it is called Malignant Hypertension . Increased intracranial pressure causes Papilledema , which is visible on Ophthalmoscopic examination of the Retina .


Complications

While elevated blood pressure alone is not an illness, it often requires treatment due to its short- and long-term effects on many organs. The risk is increased for:


Pregnancy

See Also: Hypertension of pregnancy


Although few women of childbearing age have high blood pressure, up to 10% develop , HELLP Syndrome and Eclampsia . Follow-up and control with medication is therefore often necessary.


DIAGNOSIS


Measuring blood pressure

Diagnosis of hypertension is generally on the basis of a persistently high blood pressure. Usually this requires three separate measurements at least one week apart. Exceptionally, if the elevation is extreme, or end-organ damage is present then the diagnosis may be applied and treatment commenced immediately.

Obtaining reliable blood pressure measurements relies on following several rules and understanding the many factors that influence blood pressure reading.

For instance, measurements in control of hypertension should be at least 1 hour after caffeine, 30 minutes after smoking and without any stress. Cuff size is also important. The bladder should encircle and cover two-thirds of the length of the arm. The patient should be sitting for a minimum of five minutes. The patient should not be on any adrenergic stimulants, such as those found in many cold medications.

When taking manual measurements, the person taking the measurement should be careful to inflate the cuff suitably above anticipated systolic pressure. A stethoscope should be placed lightly over the brachial artery. The cuff should be at the level of the heart and the cuff should be deflated at a rate of 2 to 3 mmHg/s. Systolic pressure is the pressure reading at the onset of the Sounds described by Korotkoff (Phase one). Diastolic pressure is then recorded as the pressure at which the sounds disappear (K5) or sometimes the K4 point, where the sound is abruptly muffled. Two measurements should be made at least 5 minutes apart, and, if there is a discrepancy of more than 5 mmHg, a third reading should be done. The readings should then be averaged. An initial measurement should include both arms. In elderly patients who particularly when treated may show orthostatic hypotension, measuring lying sitting and standing BP may be useful. The BP should at some time have been measured in each arm, and the higher pressure arm preferred for subsequent measurements.

BP varies with time of day, as may the effectiveness of treatment, and Archetypes used to record the data should include the time taken. Analysis of this is rare at present.


Distinguishing primary vs. secondary hypertension

Once the diagnosis of hypertension has been made it is important to attempt to exclude or identify reversible (secondary) causes.


Blood Test s commonly performed in a newly diagnosed hypertension patient



EPIDEMIOLOGY

The level of blood pressure regarded as deleterious has been revised down during years of epidemiological studies. A widely-quoted and important series of such studies is the . The results from Framingham and of similar work in Busselton, Western Australia have been widely applied. To the extent that people are similar this seems reasonable, but there are known to be genetic variations in the most effective drugs for particular sub-populations. Recently ( 2004 ), the Framingham figures have been found to overestimate risks for the UK population considerably. The reasons are unclear. Nevertheless the Framingham work has been an important element of UK health policy.


TREATMENT


Lifestyle modification

Doctors recommend Weight Loss and regular Exercise as the first steps in treating mild to moderate hypertension. These steps are highly effective in reducing blood pressure, but easier to suggest than to achieve, and most patients with moderate or severe hypertension end up requiring indefinite drug therapy to bring their blood pressure down to a safe level. Discontinuing Smoking does not directly reduce blood pressure, but is very important for people with hypertension because it reduces the risk of many dangerous outcomes of hypertension, such as stroke and heart attack.

Mild hypertension is usually treated by Diet , exercise and improved physical fitness. A diet rich in fruits and vegetables and fat-free dairy foods and low in fat and Sodium lowers blood pressure in people with hypertension. Dietary Sodium (salt) causes hypertension in some people and reducing salt intake decreases blood pressure in a third of people. Regular mild exercise improves blood flow, and helps to lower blood pressure


Medications

''See main article: Antihypertensive s''

There are many classes of medications for treating hypertension, together called Antihypertensive s, which — by varying means — act by lowering blood pressure. Evidence suggests that reduction of the blood pressure by 5-6 mmHg can decrease the risk of stroke by 40%, of coronary heart disease by 15-20%, and reduces the likelihood of dementia, heart failure, and mortality from vascular disease.

  url http://jamaama-assnorg/cgi/content/full/288/23/2981
  author ALLHAT Officers and Coordinators for the ALLHAT Collaborative Research Group
  journal JAMA
  title Major outcomes in high-risk hypertensive patients randomized to angiotensin-converting enzyme inhibitor or calcium channel blocker vs diuretic: The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)
  year 2002
  month Dec 18
  volume 288
  issue 23
  pages 2981-97
  id PMID 12479763


  url http://contentnejmorg/cgi/content/abstract/348/7/583
  author Wing LM, Reid CM, Ryan P et al
  journal NEJM
  title A comparison of outcomes with angiotensin-converting--enzyme inhibitors and diuretics for hypertension in the elderly
  year 2003
  month Feb 13
  volume 348
  issue 7
  pages 583-92
  id PMID 12584366



  url http://circahajournalsorg/cgi/content/full/99/15/2055
  author Wang TJ, Ausiello JC, Stafford RS
  journal Circulation
  title Trends in Antihypertensive Drug Advertising, 1985–1996
  year 1999
  volume 99
  pages 2055-2057
  id PMID 10209012


Physicians may start with non-thiazide antihypertensive medications if there is a compelling reason to do so. An example is the use of ACE-inhibitors in diabetic patients who have evidence of kidney disease, as they have been shown to both reduce blood pressure and slow the progression of Diabetic Nephropathy . In patients with coronary artery disease or a history of a heart attack, beta blockers and ACE-inhibitors both lower blood pressure and protect heart muscle over a lifetime, leading to reduced mortality.

Commonly used drugs include:

The aim of treatment should be blood pressure control (<140/90 mmHg for most patients, and lower in certain contexts such as diabetes or kidney disease). Each added drug may reduce the systolic blood pressure by 5-10 mmHg, so often multiple drugs are necessary to achieve blood pressure control.


REFERENCES


alpha blockers: e.g, terazosin,prazosin


SEE ALSO



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