One reason that is often not looked upon for the cause of headaches during and after dialysis is due to your BUN and other waste products. This is often referred to as a BUN Headache.
To make it simple, it is your brain swelling as the result of your brain not being able to release wastes - mainly BUN as fast as your body tissues. This causes your brain to pull extra water, resulting in swelling. In other words, your brain swells during dialysis. This is what causes your headache. It usually lasts a few hours after dialysis or until the body normalizes itself again.
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