I don't know a thing about your brothers condition but if it happens when he stands up or in warm temps it is a common symptom of lyme. I have it as do many here.
It could be part of the dysautonomia that so many of us have. It is diagnosed as Neurally mediated hypotension or orthostatic hypotension. A fast pulse often goes along with it. That is call postural orthostatic tachycardia. POTS for short.
Tilt table testing through a cardiologist will often be used to diagnose this problem.
Don't know if that is what is happening in your brothers case. It can be a side effect of some medications and it's possible that some herbs could also cause the problem.
This is also a common diagnosis in people with chronic fatigue syndrome. In my opinion, many of that patient population could actually have lyme disease.
Terry I'm not a doctor
Posted by drewby (Member # 15253) on :
I just got diagnosed with NMH-Neurally Mediated Hypotenstion via a Tilt Table Test.I have chronic lightheadedness and episodes of near fainting for the last few years.
All other cardio tests were normal. I believe this is cause by Lyme. My treatment is to increase liquids and salt and STOP caffeine. They want to try that before drugs.