I had a high potassium-sodium ratio on a hair mineral analysis and a recent blood test found potassium slightly above normal.
Also, I'm hypothyroid and taking thyroid greatly increased the strength and frequency of periodic paralysis. I avoided it for years because it made me feel worse somehow. Thyrotoxic periodic paralysis is caused by hyperkalemia.
These three things point toward me having hyperkalemic periodic paralysis. However, I have hyperreflexia during paralysis, and when I had an EKG during paralysis in the past, it was apparently normal, which would seem to rule out hyperkalemia.
There's no sign of anything being wrong with me besides in the CNS. Can channelopathy be present only in the CNS? If not, then it's some other problem.
For example, hypothyroidism increases lactate production, which can damage cells. I was hypothyroid since I was a kid. However, if there are already issues with orthostatic intolerance, like I had, thyroid may make things worse by demanding more nutrients of an insufficient circulatory system.
Maintaining blood volume and circulation to the head is important. I recently got tired of hauling and drinking so much fluid and having to urinate, so I stopped that, and now I experience respiratory and cardiac dysautonomia during PEM that might end up killing me. Avoiding PEM wasn't worth the cost of doing additional damage.