Postural tachycardia syndrome in children and adolescents.

Postural tachycardia syndrome is a chronic condition with frequent symptoms of orthostatic intolerance or sympathetic activation and excessive tachycardia while standing, without significant hypotension. Orthostatic symptoms include dizziness, lightheadedness, blurring of vision, near faints, weakness in legs, poor concentration, nausea, and headaches. Somatic symptoms include fatigue, sleep disorder, widespread pain, abdominal pain, and menstrual irregularities. Psychological problems may overlap with physical complaints. This review discusses the normal physiology of orthostatic change, different pathophysiological mechanisms of postural tachycardia syndrome, including hypovolemia, venous pooling, autonomic neuropathy, and hyperadrenergic responses. In addition, an outline for management tailored to the patient's clinical syndrome is presented, along with concluding thoughts on future research needs.