Syncope Orthostatic Intolerance true true A condition characterized by development of symptoms while standing. It is an autonomic nervous system disorder and the symptoms are relieved once the person sits back down. Symptoms include heart palpitations, sweating, anxiety, lightheadedness, hyperpnea, anxiety, and blurred vision. C1535893 Orthostatic Intolerance Finding Orthostatic intolerance may result in syncope with changes in posture. Chronic orthostatic intolerance / the postural orthostatic tachycardia syndrome (POTS) in adolescents and adults can produce symptoms of light-headedness, dizziness, blurred vision, sweating, headache and nausea. Orthostatic Intolerance C84973 https://www.ncbi.nlm.nih.gov/pubmed/18777476