I have to repeat my synacthen test (again)

Here’s hoping for third time lucky…The synacthen test is the diagnostic test for adrenal insufficiency. It works out if your adrenal gland is working and/or if your pituitary gland is sending the hormone ACTH to the adrenal gland to tell it to make cortisol. I did a repeat one last year because a doctor thought I might not be cortisol deficient anymore and said I could come off steroids. The test showed he was very wrong, my adrenal gland was making only a dribble of cortisol and I definitely did need steroids. However, because they weren’t expecting those test results, they only ran the cortisol bit of the test and not the ACTH bit, despite me asking them to. And now it’s been decided that we need that result too, so I have to repeat the test, which I’m a tad grumpy about.

The test itself is easy. Blood test, injection, 2 more blood tests, done within an hour and fifteen minutes. Easy peasy. But if you’re already on treatment for AI, it means coming off steroids beforehand, which is not good since you get told at diagnosis ‘if you miss a dose, you could die’. Last time, I had to come off steroids for about 28 hours, which was horrendous and I ended up in resus soon after. This time, they’ve said to do 15 hours. It’s a bit like saying ‘we’re going to take some of the oxygen out of the room for a little while. Chances are you’ll probably be fine, you’ll just feel really crappy, you might hallucinate, be in pain, perhaps fall into a coma, but most people are alright so you will be too‘. A lot of it, I’m aware, is psychological. I didn’t die before I started treatment from low cortisol, so chances are I won’t now. Except for emotional distress or injury or illness, so please keep everything nice and calm for me and germ-free for the next couple of weeks 🙂

So, you might be thinking I have a diagnosis of AI, so why do we have to do the test again? Especially as I’ve already done two, and the results are always going to be slightly skewed because I’m on steroids.

It’s because we’re trying to work out if I’m primary or secondary AI. The treatment for AI is largely the same either way, but it might help get to the bottom of some of the other weird endocrine things which are going on. In a synacthen test, here’s what’s supposed to happen:

If you’re primary AI, your first cortisol blood test will be very low but your ACTH level will be likely very high. This is because your pituitary is constantly sending out ACTH to the adrenals desperately trying to make them work to produce cortisol and wondering why they’re being stubborn and doing nothing. When you’re given the ACTH injection, you’ll end up with more ACTH in your blood and still no cortisol. Your adrenal glands don’t work. The primary problem is with the adrenal gland.

In secondary AI, you might have a cortisol reading to start off with, but it’s likely pretty low and your ACTH will be non-existent. So ‘normal’ people at 8am should have a cortisol level of about 500 ish, give or take. Someone who is secondary AI might have a baseline reading of 200-300 or less, but it’s still nowhere near what it should be. Sometimes it might be 400 ish. The important thing with SAI, is how your adrenal gland responds to the ACTH injection. If it ‘stimulates’ in response to ACTH, e.g. roughly doubles the cortisol, it means your pituitary isn’t functioning properly and there isn’t any/enough ACTH coming from it to make the adrenal gland work. So the problem isn’t with the adrenal gland itself even though it looks that way, but because the pituitary isn’t doing its thing it’s causing a secondary problem.

I’ve done 2 synacthens now and failed both. However, my results are a bit odd which is why we really could do with that ACTH result. Last year when I did the test the cortisol results were (nmol/L):

Baseline (before injection): 18

30 minutes blood test: 54

60 minutes blood test: 65

So I had a very slight amount of cortisol production to start with. But bearing in mind a healthy person’s cortisol at that time of day is 500, that’s very low. Then it did increase a bit, although it’s still far from the ‘safe’ range which starts at 150 (ish). In other words, I shouldn’t have been walking around and talking before the test, but somehow was. I saw a consultant a few weeks ago who looked at the result and said ‘that’s your synacthen? How is that right?’. I had a really low reading to start with, and then it didn’t really move (like primary). But it did double the result technically (like you’d expect in secondary), but if my adrenals were working properly and I was actually secondary, it should have gone higher than that. You can also be both primary and secondary AI at the same time ie the adrenal glands don’t function well and the pituitary also isn’t doing its thing.

I could speculate about what my last synacthen potentially means until the cows come home but it’s a pretty pointless exercise because, knowing my luck, my endocrine system will throw a curve ball and it’ll be doing something completely different at this synacthen. A lot has changed in the past year, but I wouldn’t say no to a miraculous recovery though!! The reasons I want to have some kind of answers from it include:

– the potential of some other treatments e.g. replacement ACTH or aldosterone which might help some of my symptoms

– we might be able to see if there are any other endocrine loops which are broken and treat those

– hopefully my baseline dose will be looked at again. That’s another blog post for another time though.

– I hopefully won’t have to have repeated conversations with other doctors which include me trying to explain the differences between primary and secondary and why we’re not sure which one I have, but can they please bear both in mind while treating me ‘just in case’ it helps. Most doctors don’t understand both versions and only remember one of them or get confused, so it’ll be good to just have one to talk about!

Hormones are fascinating. Did you know the adrenal cortex is made up of 2 bits and the bit that currently doesn’t work in me is responsible for about 90 hormones? But I’m only taking medication to replace one of those. 1 out of 90. Now you can see why I don’t give people much sympathy when they blame their bad moods on hormones- if you think PMT is bad, you should try having 89 hormones missing completely! (Guess which bit of your body is responsible for PMT as well…!)


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