It depends on the cause, it can be related to vitamin/mineral deficiencies with B-vitamins, but in cases like mine, it was caused by gluten ataxia. Gluten ataxia the immune system will also attack the brain and or nervous system. In this case, it can show up on an MRI as white spots. Someone will probably link you the medical info I will see if I can find it post it later.
The gluten ataxia in most cases is very sensitive more so than plain celiac. For me, tiny amounts may cause the PN, but a full-on gluten dosing or bad CC case can cause a complete motor control loss for an hour or so and loss of heat/cold sensitivity and pain sensitivity for months. Along with balance issues, coordination issues, etc.
The B-vitamin issue with b12 primarily is as mentioned above onother common issue, due note do the the nature and soulablity of b-vitamins supplementing 2-3times a day in split doses is suggested. Having celiac also makes this a issue and many do well with supplementing our intakes. I personally take Liquid Health Mega Energy B-complex (Formally called Energy & Stress) and Liquid Health Neurologic 1tbsp each twice a day in a beverage.
I will attach some photos from a medical study guide on Nutrient Deficiencies.