Idiopathic or essential hypertension is the most common, affecting approximately 40 million American adults. Men are more frequently affected than women until the postmenopausal age; black and Hispanic men and women are more commonly affected than whites.
In labile or intermittent hypertension, hypertension occurs only in certain circumstances, such as visits to the physician, stress, or exercise. These patients are at increased risk for the development of chronic hypertension.
In isolated systolic hypertension, systolic blood pressure is elevated but diastolic blood pressure is 90 mmHg. This type occurs typically in the elderly, in whom large-vessel compliance is decreased secondary to atherosclerosis and age. Systolic blood pressure is usually 160 mmHg. Recent studies demonstrate that decreasing systolic blood pressure to 160 mmHg in the elderly results in a significant reduction in the rate of cerebrovascular and cardiovascular accidents.
Borderline hypertension is defined as elevated blood pressure but not in the hypertensive range. Usually, these patients are in transition from the normotensive to the hypertensive state and are at increased risk for the development of chronic hypertension. Typically they have a family history of essential hypertension.
Malignant hypertension is a medical emergency requiring immediate therapy. It is characterized by marked elevation in blood pressure, usually 180/120 mmHg, and is associated with evidence of acute end-organ damage, profound intravascular volume loss, and activation of the renin-angiotensin-aldosterone axis. Patients are usually symptomatic with blurred or decreased vision, headache, confusion, or chest pain. On opthalmologic examination, the presence of papilledema diagnoses malignant hypertension, although grade III neuroretinopathic changes also may be seen. The severe acceleration in hypertension and activation of the renin-angiotensin aldosterone axis result in large- and medium-vessel vasculitis involving the renal vasculature, leading to kidney injury.
Accelerated, urgent, or emergent hypertension is a milder form of malignant hypertension in which the patient may be symptomatic but papilledema or evidence of renal injury is not present. However, due to the explosive nature of this disorder, these patients also should be treated emergently.