Proof of your medical condition may be relevant to defend against the charge that you were "under the influence of alcohol" at the time of the traffic stop. You refused testing, so the state will not have a breath test to introduce at the time of trial. If you can establish hypoglycemia, then you can use that to rebut the allegation that the officer's observations of "impairment" are a result of alcohol intoxication.
I don't see this as a civil rights question. The fact that the police mistook your symptoms as being intoxicate seems entirely reasonable and probably established probable cause to arrest you. This is a criminal law question. You can prove your defense by hiring a seasoned criminal defense attorney who can gather the evidence and possibly expert testimony to demonstrate your defense and successfully argue it to a jury. Your attorney will obtain things like videos that the police have of the incident and police reports through discovery.
The contents of your post do not raise any civil rights issues. I'm going to edit the practice area of your post to "Criminal Defense," so that it can be viewed by attorneys who practice in that area.
Ms. Berjis is licensed to practice law in the State of California. The laws of your jurisdiction may differ and thus this answer is for informational and educational purposes only and is not to be considered as legal advice. Since all facts are not addressed in the question, this answer could change depending on other significant and important facts. This answer in no way constitutes an attorney-client relationship.
From the information provided, you were having a seizure and were driving yourself to the hospital. Regardless of the cause, it is the responsibility of a driver and his/her doctors to ensure that s/he is fit to drive. I gather that none of your doctors has explained to you the dangers of driving with your condition. It is ultimately your responsibility to recognize when you are unfit to drive, and according to the facts that you provided, you were clearly impaired. Not being under the influence of alcohol or illicit drugs does not give you a free pass. If you have had such a seizure in the recent past, you may very well be convicted of OWI, depending on the laws of Iowa. Having had one seizure of the kind you describe is the trigger to alert you to the fact that you have a problem. You absolutely should hire an attorney immediately if you have not already done so.
My advice should in no way be construed as creating an attorney-client relationship.