This article reviews the diagnosis and management of the most common disorders of orthostatic intolerance: postural tachycardia syndrome (POTS) and neurally mediated syncope.
POTS is a heterogeneous syndrome caused by several pathophysiologic mechanisms that may coexist (limited autonomic neuropathy, hyperadrenergic state, hypovolemia, venous pooling, joint hypermobility, deconditioning). Neurally mediated syncope occurs despite intact autonomic reflexes. Management of orthostatic intolerance aims to increase functional capacity, including standing time, performance of daily activities, and exercise tolerance. Nonpharmacologic strategies (fluid and salt loading, physical countermaneuvers, compression garments, exercise training) are fundamental for patients with POTS, occasionally complemented by medications to raise blood pressure or slow heart rate. Neurally mediated syncope is best managed by recognition and avoidance of triggers.
Significant negative effects on quality of life occur in patients with POTS and in patients with recurrent neurally mediated syncope, which can be mitigated through targeted evaluation and thoughtful management.