Orthostatic disorders in hypertension

Orthostatic hypotension is commonly found in hypertensive patients with the prevalence between 10-30%. Orthostatic hypotension can be classified as either (a) “hyperadrenergic” indicating that the autonomic nervous system is responding appropriately to an excessive postural fall in venous return, or (b) “hypoadrenergic,” indicating a defective reflex compensation to a normal fall in venous return. Patients with hyperadrenergic states should be treated according to the cause of intravascular volume depletion. Patients with hypoadrenergic orthostatic hypotension require both nonpharmacologic and pharmacologic intervention to reduce the postural symptoms. Although diuretics are first-line antihypertensive therapy for most patients with hypertension, they should be avoided in patients with hypoadrenergic orthostatic hypotension. Supine hypertension in the setting of autonomic failure is a rare indication for short-acting vasodilator therapy at bedtime. Orthostatic hypertension (elevated blood pressure only when standing) is less common than orthostatic hypotension and often goes undetected. The pathophysiology is not well understood but overactivity of sympathetic nervous system may play a major role. Alpha-adrenergic receptor blockade should be considered.