Hi Ava, I'm so sorry about your niece having RSD. I know the passing out is very scary. It has happened to me many times. I am 64 and had RSD 16 years. Wasn't diagnosed for 5 years. RSD is a disorder of the autonomic nervous system. Which is composed of the sympathetic nervous system, parasympathetic nervous system, vegas nerve. If you look up those words and their functions you will understand the conditions of a body with RSD. With RSD there is no automatic regulation of body temperature-hot or cold- heart rate-fast or slow- blood pressure high or low- it can fluxuate wildly. When the blood pressure drops, too low, we pass out. I own a blood pressure kit I bought at Costco for about $40. It also has a read out on heart rate.
I have 'signs' before passing out- my hearing diminishes,feel hot sweaty,
sometimes nauseous, need to sit down-weak. When I feel this way, I need to immediatly sit down and elevate legs for the blood to get to brain. I'm usually out for a few minutes, but have been out for several hours. The first time this happened to me I was out for several hours and the paramedics
couldn't find a pulse and told my husband I was gone. Was in icu for 4 days/
I actually am on blood pressure medicine for high blood pressure. Also am on medication for too fast heart rate tachycardia. When the heart rate gets too low it's called bradycardia. That can cause passing out.
If you put in these different words in internet and look under wikipedia for definition, it will explain their functions.
I don't know the answers for her not knowing her name etc. I would think she needs to see a neurologist familiar with RSD. I always know my name, where I am etc. I have no memory of the time while out of even how I get from the floor to couch etc. immediatly after coming out of it.
I hope this helps. The most common cause of passing out is the drop in blood pressure. I would be concerned about her not having memory of who she is. When I'm out I have no memory of being out. Hope this helps. There is a medical term for this condition, but I forget what it is. I can't imagine how scary this is for your niece too. Let me know how she is doing and what the Dr. says. I saw my Dr. about 2 weeks ago and told her about my recent spells of passing out and the first question she asked me is '"if I remember who I am and where I am when I wake up" My answer was yes. So her asking me that concerns me about your nieces symptoms. Does that make sense? Take care, loretta