Hypertension Diagnostic Criteria and Secondary Causes

Hypertension is a sustained increase in arterial pressure that raises the workload on the heart and exposes blood vessels, kidneys, brain and retina to cumulative injury. Primary, or essential, hypertension has no single identifiable cause. Increased sympathetic activity, renin–angiotensin–aldosterone system activation, sodium retention, vascular resistance and arterial stiffness interact to keep pressure elevated. Secondary hypertension has a discrete cause that may be treatable or reversible. Renal disease, primary aldosteronism, obstructive sleep apnea, renovascular disease, pheochromocytoma, coarctation of the aorta and endocrine disorders can all produce this pattern. The distinction matters because simply adding another antihypertensive may miss a correctable driver and delay protection of the affected organs. A diagnosis should not be attached to one hurried reading. Pain, anxiety, recent nicotine, caffeine or exercise, a full bladder, talking, an incorrect cuff or poor positioning can raise the measurement temporarily. Conversely, a normal clinic value does not exclude hypertension if the patient’s pressure rises at home or during sleep. Current Canadian guidance defines hypertension as confirmed BP at or above 130/80 mm Hg. Confirmation with home BP monitoring or 24-hour ambulatory...