Failed short synacthen test, does anyone know w... - Thyroid UK

Thyroid UK

139,414 members163,651 posts

Failed short synacthen test, does anyone know why I would have a normal baseline for the morning but then barely any response to the stim?

Lucy___ profile image
13 Replies

Hi everyone

I've been on low dose steroids since March in an effort to tackle my substancial exhaustion, around 10mgs total a day, sometimes 7.5mg so very low dose.

Unfortunately last week I failed my SST with the following results :

341 start

396 at 30 mins

448 at 60 mins

The previous stim done in January was :

315 start

520 at 30 mins

611 at 60 mins

So a huge deterioration, not in the baseline which has stayed pretty similar but the stimulation of the adrenals which has all but stopped.

I have become very tanned over the last 6 months which has upset me hugely.

Anyway, the question is, obviously they are now suspecting adrenal insufficiency or Addison's (waiting for the ACTH to come back) but does anyone know why my adrenals would be able to produce a normal amount of cortisol for the baseline (which suggests my adrenals are normal and working as the baseline is a very good number) BUT can't work when stimulated further by the ACTH test?

I am really really puzzling to understand this and it's driving me mad.

If anyone could explain or knows why please let me know but I appreciate people might not know.

Thanks

Written by
Lucy___ profile image
Lucy___
To view profiles and participate in discussions please or .
13 Replies
greygoose profile image
greygoose

Because your adrenals are failing and incapable of reacting to the stimulus, presumably. And I would not have said that 341 was a good baseline - but I'm no expert, of course.

The point of an SST is to find out why your cortisol is low. Is it due to adrenal incapacity or is it due to lack of stimulation from the pituitary?

If your adrenals respond to the stimulation injection, then the adrenals are healthy and it's the pituitary at fault.

If they don't respond to the stimulation then it's the adrenals that are at fault.

But, you'll know more when you get the results of the ATCH test. :)

Rainbow-Lover profile image
Rainbow-Lover

The ‘tanning’ you describe could be related to a liver condition or it could be hyperpigmentation which is a symptom of failing adrenal function. Hyperpigmentation is normally found in the creases and folds of the skin though.

Take care and I hope you soon get some answers.

McPammy profile image
McPammy

I’ve had 3 synacthen tests over a few years. All came back that I past. It could be low ACTH as the synacthen is false ACTH injected. Did you feel any different after the test for a few hours or a day maybe. I know I felt fantastic for a day but then went back to feeling normal. The range is normally 155-650 in my experience. I get my 9am cortisol checked every 3 months and it’s usually around 280. But if I’ve been unwell it goes higher. I had covid recently and it was 350. I think your baseline of 341 start is pretty good. My understanding is that cortisol rises when we are unwell as it’s our own natural steroid and also rises during the fight or flight we can experience. So you don’t want it high it needs to be mid way in the range normally. My guess is it has lowered on your recent synacthen test from previously is because you are on hydrocortisone medication. If you take steroids your own steroids (cortisol) drops. You were not on steroids for your first synacthen test but was for the second test when your response is lower. Why were you put on hydrocortisone if your response was better previously? Steroids can be detrimental if not administered correctly.

Although I passed my synacthen tests my baseline was pretty low 155 (155-650) at 9am. What I found my problem was that my T3 was extremely low 3.9 (3.7-6.0). So I’m a very poor converter of t4 to t3. Privately I was trialed on t4 plus t3 medication. Oh boy oh boy what a huge improvement that made. From unable to walk properly or even sit up to walking briskly and doing gardening quite quickly. A few weeks later I had my normal 9am cortisol blood test and my level had increased hugely from 155 to 450. It’s settled now around 280 at 9am. So, for me my fix was the addition of T3. Which also fixed many other issues I was having. Have you checked your thyroid TSH, t4 and importantly t3 levels. Why was you prescribed hydrocortisone medication in the first place, did they rule out low t3 or low acth first??

humanbean profile image
humanbean in reply to McPammy

It could be low ACTH as the synacthen is false ACTH injected.

I'd use the word "artificial" (or "synthetic") rather than "false". They inject something called tetracosactide which is an artificial form of ACTH.

bnf.nice.org.uk/drugs/tetra...

CoeliacMum1 profile image
CoeliacMum1

Was you on steroids when tested?

That can invalidate reading, I assume the consultant or nurse looking after you asked you to come off or a plan of how to navigate this if coming off was totally impossible.

I had short synacthen test a couple years back now… I have steroid inhalers and was told I had to come off week before as that can give false readings… I could take ventolin if required but was to limit that if I could.

My assumption for me is steroids in inhalers over such long time are possibly causing some adrenal issues periodically… I have been on them good 40yrs… even though lowered my dose and asthma is well managed.

I have the tanning like thing over lower arms and some patchy bits on my neck but told could be high blood sugar … which I didn't have, so I also had glucose tolerance test & Blood sugar checked whilst at it… can’t say if sun damage as that was another theory…it does react and darken and can go redder when in the sun to be fair.

Melasma and hyperpigmentation caused by different things but numerous things it seems.

Look up thyroid-induced melasma, and thyroid and hyperpigmentation… apparently it can cause it too.

humanbean profile image
humanbean

If you want more information on the Short Synacthen Test (SST), the article on wikipedia is unusually good :

en.wikipedia.org/wiki/ACTH_...

For information on the different types of Adrenal Insufficiency, this link is worth reading :

en.wikipedia.org/wiki/Adren...

The way the SST is carried out by UK hospitals means that doctors rarely test ACTH. As a result they can diagnose Primary Adrenal Insufficiency (if it exists) but not Secondary Adrenal Insufficiency (if it exists).

In other words, they test the amount of cortisol being made by the adrenal glands during the SST, but they rarely test the amount of ACTH produced by the pituitary.

The annoying thing is that doctors say Secondary Adrenal Insufficiency is rare, but it seems likely that they consider it to be rare because they rarely test for it. It's a self-fulfilling prophecy!

Another useful link...

See pages 68 - 70 in this document called the "Endocrine Bible" :

imperialendo.co.uk/Bible202...

greygoose profile image
greygoose in reply to humanbean

Same as secondary hypo. They assume that everybody has a perfectly functioning pituitary - whether they do or not!

posthinking01 profile image
posthinking01

Look at DHEA deficiency - I have suffered for years and then after 25 years it is thought my DHEA has been low all my life. Easy to rectify but run past your medical people first.

Incoguto profile image
Incoguto

Hyperpigmentarion can also be from being hypo, kinda more like yellowish skin. Your adrenals seem to be working, but maybe your pituitary isn't, which could also be caused by low ft3.

Lucy___ profile image
Lucy___

Thank you everyone, I'm just reading all comments and taking them onboard 🤗

yes I do wonder if my skin colour is due to my low T3 level - it's always 3.7 on NHS testing and 3.1 on medichecks testing. My T4 is always 16 on NHS testing and 11 on medichecks.

But they will not do anything with my T3 until they know definitively about my cortisol and adrenals.

I have turned much more pronouncedly tanned in the last 6 months though which is a worry.

My liver enzymes are completely normal so it isn't due to anything to do with my liver.

They have been doing some other tests - IGG4 which was normal and more recently my A.C.E which was low at 20 as reference range is 20 - 70 though reading up, this might be affected by the betablocker I'm taking.

Basically in a nutshell I was put on steroids because AI was suspected due to my lowish cortisol tests and odd other tests like prolactin, DHEA, T3 / T4, renin and FSH.

I was initially put on 10 / 5 / 5 but found that was far too much so we agreed on 7.5 / 5 and sometimes 2.5 if I felt I needed it and I started to feel better on that dose.

I was on this dose from April until June.

At the end of June I started to get the heabies about being on steroids in case they gave me steroid induced AI as I didn't have a definite diagnosis so off my own back I started dropping my dose down to 5 / 2.5 and since then there has been a gradual decline in my energy levels and abilities to do anything.

They did tell me that the doses I was on were low enough not to trigger AI because anything below 10mgs is a physiological dose and unlikely to trigger AI but still I was nervous.

So from June onwards I've only been on 5 / 2.5 per day.

They were doing another SST just as a matter of course last week as my NHS endo actually suspected hypopituitarism and had completely ruled out primary AI due to my previous passed SSTs. They were only looking at hypopituitarism and secondary.

I took a 10mg hydro 24 hours before my test as I was feeling ill and needed it but then had nothing for 23 hours except a small dab of 1% hydro cream which I washed off almost immediately. The endo nurse said that wouldn't affect the test.

After my SST I felt dreadful, I couldn't stay awake the rest of the day, literally couldn't keep my eyes open.

Anyway we all expected me to pass the SST and probably give ambiguous results so it was a bit of a shock to see my adrenals had done sod all 😬

I'm now stuck in a situation where I dont know if I have steroid induced AI (though I have spoken to a number of doctors and experienced people and nearly everyone has said they have never seen steroid induced AI happen in such low levels of steroids) or whether I have secondary AI from a pituiatry problem or whether for some crazy reason I've managed to develop primary AI in a matter of months.

I know the ACTH test will be able to tell us if its primary or secondary but I don't think it can tell us if its secondary or steroid induced secondary.

And I'm scared shitless because I don't know whether to keep taking my steroids, try to wean off if it is steroid induced before I do further damage or whether I actually need to up my dose because I have genuine AI and am not taking enough.

I can't speak to my endo until the end of the month and I'm driving myself crazy trying to figure out what to do.

It doesn't help that the last few nights Ive woken up feeling very disoriented around 2am and had bad heart palpitations after I've woken and I'm starting to worry that my cortisol is too low at night which I know realistically it probably isn't as it's normal for cortisol to drop very low but this entire thing is freaking me out a bit tbh.

Incoguto profile image
Incoguto

I'd just say one thing. You most likely need a trial of thyroid meds. I'd take a guess that's why your cortisol is low and your pituitary isn't working correctly. I'd be fighting for that now.

Lucy___ profile image
Lucy___ in reply to Incoguto

Thank you, it's something that I will bring up with my Endocrinologist when I speak to him. It has been a battle to get them to consider thyroid as they say my T3 and 4 are within normal parameters 🙄 but equally I've been nervous to go on them too because I really struggle with heart palpitations and I've seen that alot of people get worse palpitations on thyroid meds.

Maybe I just need to try and see how I get on

Incoguto profile image
Incoguto in reply to Lucy___

Palpitations can be from low thyroid levels, many people have them. I was treated with normal in range ft3 ft4 and tsh, but abnormal hashis antibodies and a lot symptoms. You need a good doctor for sure

Not what you're looking for?

You may also like...

Low serum cortisol 9am 75nmol

year ago and was Baseline 127nmol 30 mins 527 60 mins 499 never seen 60 min cortisol go...

Does anyone know how I would have become Hypo?

Test results imply all is normal but my symptoms are so debilitating and similar to hypothyroid. Does anyone have any ideas?

checked and though testosterone normal, progesterone very low. I had a full blood count at the...

Short Synacthen test tomorrow, should I bother and does it make you feel unwell?

checking for addisons, I'm really nevous about having a reaction to the test aswell, silly I know....

ACTH Cortisol test enquiry

about * 15 in ACTH results. I understand that the ACTH test is solely testing for Addisons, (I...