Chronic hypertension classification

Hypertension Main page
Overview
Causes
Classification Primary Hypertension Secondary Hypertension Hypertensive Emergency Hypertensive Urgency
Screening

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Classification of Hypertension

Hypertension is considered to be present when a person's systolic blood pressure is consistently 140 mmHg or greater, and/or their diastolic blood pressure is consistently 90 mmHg or greater. Recently, as of 2003, the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure has defined blood pressure 120/80 mmHg to 139/89 mmHg as "prehypertension." Prehypertension is not a disease category; rather, it is a designation chosen to identify individuals at high risk of developing hypertension. The Mayo Clinic website specifies blood pressure is "normal if it's below 120/80" but that "some data indicate that 115/75 mm Hg should be the gold standard." In patients with diabetes mellitus or kidney disease studies have shown that blood pressure over 130/80 mmHg should be considered high and warrants further treatment. Even lower numbers are considered diagnostic using home blood pressure monitoring devices.

Blood Pressure	Systolic (mm Hg)	Diastolic (mm Hg)
Optimal	< 120	< 80
Normal	< 130	< 85
High Normal	130-139	85-89
Mild Hypertension	140-159	90-99
Moderate Hypertension	160-179	100-109
Severe Hypertension	180-209	110-119
Very Severe Hypertension	> 210	> 120

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.

• Over 90% of adult hypertension has no clear cause and is therefore called essential/primary hypertension. Often, it is part of the metabolic "syndrome X" in patients with insulin resistance: it occurs in combination with diabetes mellitus (type 2), combined hyperlipidemia and central obesity.
• Secondary hypertension is more common in preadolescent children, with most cases caused by renal disease. Primary or essential hypertension is more common in adolescents and has multiple risk factors, including obesity and a family history of hypertension.

Secondary hypertension

Secondary hypertension by definition results from an identifiable cause. This type is important to recognize since it's treated differently than essential hypertension, by treating the underlying cause of the elevated blood pressure. Hypertension results compromise or imbalance of the pathophysiological mechanisms, such as the hormone-regulating endocrine system, that regulate blood plasma volume and heart function. Many conditions cause hypertension, some are common and well recognized secondary causes such as

• Renovascular Hypertension: Due to fibromuscular dysplasia and renal artery stenosis. In both conditiions, increased blood pressure occurs due to narrowing of arteries supplying to the kidney.
• Pheochromocytoma: Caused by an excessive secretion of norepinephrine and epinephrine which promotes vasoconstriction
• Hyperaldosteronism (Conn's syndrome): Idiopathic hyperaldosteronism, Liddle's syndrome (also called pseudoaldosteronism), glucocorticoid remediable aldosteronism
• Cushing's syndrome - an excessive secretion of glucocorticoids causes the hypertension
• Hyperparathyroidism
• Acromegaly
• Hyperthyroidism
• Hypothyroidism
• Chronic Kidney disease
• Coarctation of Aorta
• Drugs: Oral Contraceptives, steroids, NSAIDs, nasal decongestants with adrenergic effects, MAOIs, adrenoceptor stimulants.
• Scleroderma
• Neurofibromatosis
• Pregnancy-unclear mechanism
• Obstructive sleep apnea
• Fever: unclear etiology
• Liquorice
• White coat hypertension: that is, elevated blood pressure in a clinical setting but not in other settings, probably due to the anxiety some people experience during a clinic visit.
• Perioperative hypertension is development of hypertension just before, during or after surgery. It may occur before surgery during the induction of anesthesia; intraoperatively e.g. by pain-induced sympathetic nervous system stimulation; in the early postanesthesia period, e.g. by pain-induced sympathetic stimulation, hypothermia, hypoxia, or hypervolemia from excessive intraoperative fluid therapy; and in the 24 to 48 hours after the postoperativ period as fluid is mobilized from the extravascular space. In addition, hypertension may develop perioperatively because of discontinuation of long-term antihypertensive medication.