Or would that seem too complaining/combative/passive aggressive?
I would leave that out and not because of the tone of the additional information. The letter and its concerns are medical. I would keep it that way for now. You can bring other factors and circumstances in as appropriate if a back-and-forth correspondence develops. As written, your first letter is really concise and a strong plea. Don’t attach awkward bits and bobs to your aerodynamic masterpiece, they’ll just introduce drag. Less is more sometimes.
This reminds me of the Call of Duty Black Ops edition Jeep on the road the other day. Felt completely surreal.