--given the immune function of the gut, dysregulation there might lead to autoimmunities with neuropathy as a symptom.

And, alcohol has been implicated in many neuropathies both through direct action and through impacts on nutrition--a lot of heavy drinkers suffer from vitamin deficiencies that themselves may result in neuropathy

Since Liza Jane's testing sheets were brought up, what sort of serological testing have you had? There are tests for numerous autoantibodies, but given the less length dependent and rapid presentation you mention, the obvious investigatory roads include toxins, and gut autoimmunities such as Crohn's anc celiac.