Well, it is true that PN can result from hypothyroid.

That is where mine comes from.

My PN improved about 90% after stabilizing my low thyroid.
I am left with the residual 10% which is not severe.

Now that I am much older, I do have numbness sometimes in my right hand, when my blood sugar gets too low. If I eat something then, it goes away.

There are many metabolic things going on inside people. We all are reacting in some way to our toxic environment.

Our 13 yr old cat has a thyroid nodule. If one searches thyroid issues in felines, there appears a link to environmental contaminants that are thyroid disrupters.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2612591/

Pet cats have been increasingly developing thyroid issues since the 1970's and some believe this is a marker for human thyroid disruption as well.

It is very difficult to find answers for some people with chronic issues yet today.

There are things a person can do. Get tested for B12 and Vit D levels. Supplement if you are low. Expect to take charge of your test results because doctors still do not interpret them accurately where vitamins are concerned. Try to support your mitochondria with acetyl carnitine, CoQ-10. Investigate antioxidants, and apply them for their free radical scavenging actions. Grapeseed extract and quality high absorption curcumin. Avoid MSG in foods you consume. Supplement magnesium either orally or topically if you do not eat whole foods that commonly supply this critical mineral.

These interventions may help you feel better on a daily basis.