My 17 year old daughter was diagnosed with Postural Orthostatic Tachycardia Syndrome a year and a half ago. She does not pass out. Heart rate and BP readings inproved with meds, but her symptoms have not improved, except fatigue and nystagmus less severe. I am wondering what we should be looking for now, and if we just wait or check on other possibilities like Chiari Malformation. Her symptoms are ? unusual even for POTS - she has CONSTANT headache and dizziness (get worse and better but never go away), severe fatigue, noise sensitivity, nystagmus (better will gabapentin), short term memory problems - and others, less intrusive to daily functioning. Always feels like something is stuck in her throat. Always cold. Tingling extremities, poor balance, chest pain, fibromyalgia, trouble staying asleep, occasional vertigo, . . .