• Hypertension is a heterogeneous d

• Hypertension is a heterogeneous disorder that may result either from a
specific cause (secondary hypertension) or from an underlying pathophysiologic
mechanism of unknown etiology (primary or essential hypertension).
Secondary hypertension accounts for fewer than 10% of cases, and most of
these are caused by chronic kidney disease or renovascular disease. Other
conditions causing secondary hypertension include pheochromocytoma,
Cushing’s syndrome, hyperthyroidism, hyperparathyroidism, primary aldosteronism,
pregnancy, obstructive sleep apnea, and coarctation of the aorta.
Some drugs that may increase BP include corticosteroids, estrogens, nonsteroidal
antiinflammatory drugs (NSAIDs), amphetamines, sibutramine, cyclosporine,
tacrolimus, erythropoietin, and venlafaxine.
• Multiple factors may contribute to the development of primary hypertension,
including:
✓ Humoral abnormalities involving the renin-angiotensin-aldosterone
system, natriuretic hormone, or hyperinsulinemia;
✓ A pathologic disturbance in the CNS, autonomic nerve fibers, adrenergic
receptors, or baroreceptors;
✓ Abnormalities in either the renal or tissue autoregulatory processes for
sodium excretion, plasma volume, and arteriolar constriction;
✓ A deficiency in the local synthesis of vasodilating substances in the
vascular endothelium, such as prostacyclin, bradykinin, and nitric
oxide, or an increase in production of vasoconstricting substances such
as angiotensin II and endothelin I;
✓ A high sodium intake and increased circulating natriuretic hormone
inhibition of intracellular sodium transport, resulting in increased
vascular reactivity and a rise in BP; and
✓ Increased intracellular concentration of calcium, leading to altered vascular
smooth muscle function and increased peripheral vascular resistance.