A sustained diastolic pressure greater than 90 mm Hg and a sustained systolic pressure in excess of 140 mm Hg is considered to constitute systemic arterial hypertension.
Essential, primary, or idiopathic hypertension is systemic hypertension of unknown cause. More than 90% of all cases of hypertension are in this category. Secondary hypertension is symptomatic hypertension of known cause. Fewer than 10% of all cases of symptomatic hypertension are in the latter category.
Malignant hypertension follows the accelerated course and is characterized by extreme blood pressure elevations, sudden onset, evidence of severe, generalized vascular damage, including severe retinopathy, hypertensive encephalopathy, hematuria, and renal dysfunction.
Types of arterial hypertension
Arterial hypertensions may be classified using various characteristics.
• Cardiac output: arterial hypertension with normal cardiac output is termed eukinetic, with high cardiac output - hyperkinetic, and with low - hypokinetic.
• Peripheral resistance: there are arterial hypertensions with normal or high absolute peripheral resistance.
• Blood volume: arterial hypertension may be associated with normal (volume-independent) or high (volume-dependent) blood volume.
• An increase in arterial pressure may be limited to the diastolic pressure, so-called isolated diastolic hypertension, or systolic pressure, the so-called isolated systolic hypertension. Often arterial hypertension is combined, systolic-diastolic.
• Renin activity: arterial hypertension may be accompanied by high renin activity in the peripheral blood (high-renin hypertension) or by low renin activity (low-renin hypertension).
• Clinical course: arterial hypertension may progress slowly over decades with minimal complications (benign form), or rapidly, with renal failure, and severe retinal pathology (malignant form).