Hypertension is a chronic medical condition in which the bloodpressure is elevated. It is also referred to as high blood pressureor shortened to HT, HTN or HPN. The word"hypertension", by itself, normally refers to systemic, arterialhypertension.
Hypertension can be classified as either essential (primary) or secondary.Essential or primary hypertension means that no medical cause can be found toexplain the raised blood pressure. It is common. About 90-95% of hypertensionis essential hypertension. Secondary hypertension indicates that thehigh blood pressure is a result of (i.e.,secondary to) another condition, such as kidneydisease or tumours(adrenaladenoma or pheochromocytoma).
Persistent hypertension is one of the riskfactors for strokes,heart attacks, heartfailure and arterial aneurysm, and is a leading cause of chronic renal failure. Even moderateelevation of arterial blood pressure leads to shortened lifeexpectancy. At severely high pressures, defined as mean arterial pressures 50% or more aboveaverage, a person can expect to live no more than a few years unlessappropriately treated. Beginning at a systolic pressure (which is peak pressure in thearteries, which occurs near the end of the cardiaccycle when the ventricles are contracting) of 115 mmHg and diastolicpressure (which is minimum pressure in the arteries, which occurs near thebeginning of the cardiac cycle when the ventricles are filled with blood) of75 mmHg (commonly written as 115/75 mmHg), cardiovascular disease (CVD) risk doublesfor each increment of 20/10 mmHg.
Signs and symptoms
Mild to moderate essential hypertension is usually asymptomatic. Acceleratedhypertension is associated with headache, somnolence, confusion, visual disturbances, and nausea and vomiting (hypertensive encephalopathy). Retinasare affected with narrowing of arterial diameter to less than 50% of venousdiameter, copper or silver wire appearance, exudates, hemorrhages,or papilledema.Some signs and symptoms are especially important in infants and neonates suchas failure to thrive, seizure, irritabilityor lethargy,and respiratory distress. While in childrenhypertension may cause headache, fatigue,blurredvision, epistaxis,and bellpalsy.
Some signs and symptoms are especially important in suggesting a secondarymedical cause of chronic hypertension, such as centripetal obesity, "buffalohump," and/or wide purple abdominalstriae and maybe a recent onset of diabetessuggest glucocorticoid excess either due to Cushing's syndrome or other causes. Hypertensiondue to other secondary endocrine diseases such as hyperthyroidism,hypothyroidism,or growth hormone excess show symptoms specificto these disease such as in hyperthyroidism there may be weight loss,tremor, tachycardiaor atrial arrhythmia,palmar erythema and sweating. Signsand symptoms associated with growth hormone excess such as coarsening offacial features, prognathism, macroglossia,hypertrichosis,hyperpigmentation, and hyperhidrosismay occur in these patients. Other endocrine causes such as hyperaldosteronism may cause less specificsymptoms such as numbness, polyuria, polydipsia, hypernatraemia,and metabolic alkalosis. A systolic bruit heard over the abdomen or in theflanks suggests renal artery stenosis. Also radio femoral delay or diminishedpulses in lower versus upperextremities suggests coarctation of the aorta. Hypertension inpatients with pheochromocytoma is usually sustained but may beepisodic. The typical attack lasts from minutes to hours and is associated withheadache, anxiety,palpitation,profuse perspiration, pallor, tremor, and nausea and vomiting. Blood pressure is markedlyelevated, and anginaor acute pulmonary edema may occur. In primary aldosteronism, patients may have muscularweakness, polyuria,and nocturiadue to hypokalemia.Chronic hypertension often leads to left ventricular hypertrophy, whichcan present with exertional and paroxysmal nocturnal dyspnea. Cerebralinvolvement causes strokedue to thrombosisor hemorrhagefrom microaneurysms of small penetrating intracranialarteries. Hypertensive encephalopathy is probablycaused by acute capillary congestion and exudation with cerebraledema, which is reversible.
Signs and symptoms associated with pre-eclampsiaand eclampsia,can be proteinuria,edema, andhallmark of eclampsia which is convulsions,Other cerebral signs may precede the convulsion such as nausea, vomiting,headache and blindness.