Dizziness, Syncope, and Autonomic Dysfunction in Children

Background: Orthostatic intolerance (OI) is common in the pediatric and adult population. Knowledge about autonomic nervous system and its function is a prerequisite to understanding OI. OI is not a diagnosis but a description of not tolerating to stand upright. The etiology of OI is vast and requires careful inquiry with detailed history taking, physical examination, and proper studies. Therapy of OI can be complex and prolonged and not always completely successful. Aim or Review: This review will focus on the understanding of the physiology of upright posture, intolerance of standing, terminology of various conditions, and their etiology and management. Expanding on various autonomic tests is crucial in understanding pathophysiology of OI. Key Scientific Concepts of Review: Applying knowledge of autonomic nervous system anatomy and function is key to understanding the pathophysiology of various forms of orthostatic intolerance. It is important to recognize the newly discovered confounders that could modify disease course and severity.