Chronic hypertension classification

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

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Assistant Editor-In-Chief: Taylor Palmieri

Overview

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.

JNC Classification

The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure has classified blood pressure in the follows:

Blood Pressure Classification	Systolic (mm Hg)		Diastolic (mm Hg)
Normal	< 120	and	< 80
Pre-Hypertension	120-139	or	80-89
Stage 1 Hypertension	140-159	or	90-99
Stage 2 Hypertension	>160	or	>100

Prehypertension is not a disease category; rather, it is a designation chosen to identify individuals at high risk of developing hypertension. It is not clear if treatment of pre-hypertension would improve outcomes. 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.

Classification

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.

Essential Hypertension

Essential hypertension is the most prevalent type of hypertension type, and affects 90-95% of hypertensive patients. Although there are risk factors for essential hypertension (sedentary lifestyle, obesity, increased salt intake, increased alcohol intake), by defintion there is no other disease state responsible for the occurrence of the elevated blood pressure.

Secondary hypertension

Secondary hypertension results from an identifiable cause. Recognition of secondary hypertension is critical since the management is different than primary hypertension and involves treatment of the underlying cause of the elevated blood pressure. underlying disorders that account for secondary hypertension include:

• 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. Consider this diagnosis in the patient who has a dilated cardiomyopathy (which a pheochromocytoma can cause) who still has an elevated blood pressure.
• 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.