First a little bit about PTH and its role in the human body. This is interesting. Bear with me for a bit.
The most important purpose of the Para Thyroid Hormone (PTH) to exist in the body is to control the Calcium level. Calcium is a very important element in the human body. It has a number of uses which I am not going into now. But it is really, really important. So important that there is a small organ (glands, really) that secretes this hormone just to control the Calcium level! The whole mechanism acts like a thermostat. Too little Calcium in the blood, the glands secrete more PTH which pulls out more Calcium from the Calcium stores in the body - the bones. Too much Calcium in the body, the glands reduce secretion of PTH which causes the Calcium from blood to go back into the bones.
So, now my PTH has been pretty high. It was almost 20 times the normal in May last year. Guess why? Too little Calcium in the blood, I hear you say, having understood the last paragraph pretty well. Correct! You're getting good at this. Why did I have so little Calcium. Low Calcium dialysate remember?
The problem was we (the docs?) did not think that it was due to the Calcium being low. The blood work showed that the Calcium was normal. Hint: blood tests often don't show things until they're really bad, the body kept correcting the blood Calcium level by leeching my poor bones which shouted out in pain when they could take it no more!
We kept attributing the high PTH to "long term effects of kidney disease". We kept trying to correct it with Cinacalcet, an expensive drug which attacked the symptom (high PTH) rather than the cause (low Calcium). At one point I was taking a whole lot of Cincalcet because of which the PTH did become low but it was a lost cause because the real reason was elsewhere. The moment I reduced the dose, it would rise again.
For the last 15 days, I have switched to a regular Calcium dialysate (a couple of days of high Calcium in between) and was on a high dose of calcitriol for a few days and now back to the regular dose. Guess what has happened to my PTH? Become normal, you ask again, and I commend you on your reasoning! I thought it would too. But hold your breath - it has actually become BELOW NORMAL!!!
My PTH is at 4.7. Gosh, that's really low. The journey from 1015 to 4.5 has been quite a rough one! But, it gives me the confidence that my reasoning was right. We should have stopped using the low Calcium dialysate long, long back. Well, getting the PTH back to normal shouldn't be a problem.
I am really glad its all falling into place!