I am going to address this issue with a new endocrinologist ... I too wonder if there is a relationship with the thyroid or para thyroids
The four parathyroids are connected to the thyroid and have their own blood supply. They can take a hit during the thyroid’s removal and take some time to recover. (Or they may not recover fully, which appears to be my case.) Two days after the second operation, I started to suffer from tetany and felt lousy. Thankfully, a nurse called to see how I was doing, found out, called my doctor who told me to get to emergency NOW. My veins collapsed from all the blood tests while they gave me the IV, trying to get my levels up to a safe level. My doctor came in to check on me and explained the levels I was at had me in a life-or-death situation.
Since then, I'm very cognizant of getting my calcium and vitamin D in and watch out for the physical symptoms that clues me in that I need to get more in. I keep Oscal with me at all times, just in case. Darn thing is, even when I think my levels should look pretty good, the blood tests will show I'm on the low side, bordering too low. It's a fight to get the levels I need in. Lots of milk, yogurt, and veggies with calcium are in my diet.
http://en.wikipedia.org/wiki/Chvostek_sign
One of the signs my blood serum levels are low. I can test myself and act accordingly. When my levels were so low that I was in ER, my hands and lips tingled like they were asleep - VERY annoying!, and my legs felt like that all the way through when I sat down.