Dexamethasone Suppression test: Has anyone with... - Thyroid UK

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Dexamethasone Suppression test

ChristinaT profile image
34 Replies

Has anyone with Cushings or CAH had a dexamethasone suppression test pre diagnosis? (As part of getting their diagnosis) If so could you please share with me your experience with this test? How the medication made you feel? Side effects etc?

Many Thanks

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ChristinaT profile image
ChristinaT
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Ratkinson profile image
Ratkinson

Hi , I had Cushings disease due to a pituitary adenoma and had both high and low dose suppression tests as part of my diagnosis. As far as I can remember both were fine.

Dexamethasone is a steroid so any side effect from the drug will be linked to having extra steroid. So if you do have Cushings already you will probably be used to those feelings of being a bit jittery , unable to sleep etc. If you are having the low dose test I expect you won't notice anything different at all. Hope it goes well. Rachel

ChristinaT profile image
ChristinaT in reply to Ratkinson

Hi there, thank you so much for your reply. Ive just had bloods drawn following taking a 1mg tablet last night. I don't feel much different other than I feel I have a little bit more energy (positive effect) but nothing major. I tend to stay awake at night and struggle a lot in the day so getting up early makes me feel worse than I do already. I had a synacthen test a few weeks ago and I reacted badly to whatever they injected me with (almost as though it mimicked my current symptoms). I take it from what you've said you didn't experience any change (small or big) in how you felt? Can I ask you if you did a 24 hour cortisol urine test at all? Sorry for the questions, (I hope you don't mind me asking) im just interested to hear people's experiences with the various tests

Ratkinson profile image
Ratkinson in reply to ChristinaT

Hi Christina

Yes I did lots and lots of 24 HR urines! My pituitary seemed to be blipping out extra ACTH at random so some 24 HR urines were within normal range and others way too high. In the end I did a weeks worth all at once ( an awful lot of containers) . As the Cushings progressed you could tell from looking at me that I had Cushings though , the classic "lemon on sticks, moon face, buffalo hump etc and I ate anything in site even when I was full to bursting. I put on about 4 stone in a very short period of time.

It's 18 yrs now from diagnosis so can't remember in too much detail about reactions to tests, but nothing was too bad.

Have you found the pituitary foundation website yet? Lots of really good info and a specialist endocrine nurse at the end of a phone.

Hope you get sorted

SmallBlueThing profile image
SmallBlueThing in reply to Ratkinson

From the trailer, I think they're having a patient with Cushing's on next week's "GPs: Behind Closed Doors" (Channel 5, Wednesday 3rd August, 8pm).

ChristinaT profile image
ChristinaT in reply to SmallBlueThing

I am definitely going to watch that next week. thank you for informing us of this

ChristinaT profile image
ChristinaT in reply to Ratkinson

Thank you for the information, im going to have a look at that website shortly, much appreciated. I'm the same food wise, will eat everything even when not hungry, literally cannot stop myself, aswell as the weight issues. I think im going to ask for cortisol urine test. Ive read somewhere I might be able to request this via my GP? But I'm really not sure if this is the case until I ask. I'm currently seeing a private endo and he only measured my cortisol levels after the suppression test, he hasn't measured my acth levels at all 😐. I hope you're much better now from what you were?

Ratkinson profile image
Ratkinson in reply to ChristinaT

Yes , much better than before, but as a result of the surgery I now have no pituitary function so all my hormones are now via tablets or injection. It's been an interesting journey!

Does you specialist know much about Cushings? If not you might be best getting a referral to a good centre, I was diagnosed in Oxford who were just amazing and then moved a lot , so been under 3 other specialists , none as good as Oxford and this final lot I have absolutely no confidence in at all!! Still I am quite well informed and proactive so can usually steer them in the right direction.

Fingers crossed for you.

ChristinaT profile image
ChristinaT in reply to Ratkinson

I'm so glad your in a much better place now then you were, but yes that's quite a change of direction regarding you now being on the other end of the spectrum! I hope you're able to manage your condition well.

I don't know if he's an expert in the cushings field, he is a prof of endocrinology, but said he will treat symptoms, such as mineralcorticoids for salt cravings, meds for excess body hair but the only problem with that is its made me worse in the past, because it's not treating the underlying problem. Currently I can't even take a painkiller because I react to everything and it's worsens my symptoms. He thinks I don't look like a text book patient with cushings, but he never saw me when I was well. I'm naturally a size 4/6 and have gone up to a size 14. So whilst that's not massive in the grand scheme of things it is for me. Ive had weight gain issues all my life, bouts of rapid weight gain (unexplainable) always super hungry, the amount I eat is ridiculous 🙈. Occasionally get a buffalo hump. I have unexplained oesteoporosis, random fractures, hair is very very thin, thin skin, can see my veins very prominently, mental symptoms, sometimes get dark armpits when things are really bad. Awake at night, sleep most of the day, extreme fatigue.and sweating, puffy face to the point where I literally can't cope with it, it's unbearable and I feel like I'm dying a slow painful death.

I'm going to see my GP next week and ask to be referred to a specialist centre (now you've recommended it) because the private endo ive seen isn't really investigating it properly, he hasnt tested ACTH levels or anything else.

However I have a high LH level which is usually means PcOS but I don't have that, so I might have Congenital Adrenal Hyperplasia with a possible tumour which is causing cushings symptoms aswell as adisonian type symptoms too. I get attacks/flares where all cushings symptoms are worsened, the hump shows, the abdomen looks like as ascites (even bigger than it is already) but I also get salt cravings too and pigmentation aswell as all the aforementioned symptoms, so I essentially experience both ends of the scale simultaneously during these crisis's.

Cushings or CAH I really just want to get the bottom of it all now. Thank you for taking your time to respond and sharing your experiences and providing me with some very useful information. Much appreciated.

Ratkinson profile image
Ratkinson in reply to ChristinaT

Gosh you are having a really tough time, I think you will find the pituitary foundation really usefull - I agree you do need to find out what is causing it and not just treat the symptoms. Give the nurse a call , she is really good, she may be able to suggest someone good local to you.

ChristinaT profile image
ChristinaT in reply to Ratkinson

Thank you so much, I definitly will, very useful information you have provided me with, im very grateful

SmallBlueThing profile image
SmallBlueThing

I had about three hours' sleep and was wide awake at 5am. I was a bit jittery, not helped by the blood test being 10 minutes late. My waist measurement has increased. Not yet received my results.

ChristinaT profile image
ChristinaT in reply to SmallBlueThing

Poor you 😞 I hope you get your results soon enough. Ditto re waist, ive gained a lot of weight on my abdomen, I sleep terribly too. Awake at night and don't fall asleep until 5 am most nights. 😒 lets hope we both get to bottom of it asap.

SmallBlueThing profile image
SmallBlueThing in reply to ChristinaT

A few months ago I thought my enlarged abdomen was ascites. The recent waist measurement increase is more noticeable and has happened since taking the dexamethasone. I suppose saliva testing isn't done on the NHS, but makes me wonder why 24 hour urine wasn't offered.

I've installed f.lux on my PC to alter the screen colour at night, and do feel a bit sleepier at about 10:30pm, but still get the "second wind" at midnight.

ChristinaT profile image
ChristinaT in reply to SmallBlueThing

So dexmethasone worsened your symptoms? My abdomen goes like that periodically too I become very very unwell (see my reply above) we sound very similar in terms of that particular symptom. Are they going to give you a scan at any point? I still really would like to do a urine test. Ive done a salova test but still awaiting results to come back

SmallBlueThing profile image
SmallBlueThing in reply to ChristinaT

I've read someone saying they felt better having taken it, and I suppose I did, too, albeit jittery. However, my sleep pattern seems less satisfactory over the following week. But then, a couple of months ago I was awake until 5 or 6am, and earlier in the year I couldn't stay awake in the middle of the evening.

I misinterpreted the meaning of the test, thinking the dexamethasone blocked cortisol and not realizing it simulates it so we get an extra amount if affected.

It's my third endocrine hypertension test but apart from being a fat night owl I'm not typically Cushingoid. I thought Conn's syndrome was more likely. Just hope I'm not left waiting another four months to be told the test result was negative (not that I want Cushing's!). Having online access to results at the surgery I'm now back to delays and a sense of paternalism for this hospital-arranged test.

ChristinaT profile image
ChristinaT in reply to SmallBlueThing

I hope you manage to get it sorted out soon, I know how frustrating this all is. Fingers crossed for you.

I though dexamethasone suppressed cortisol, well if not cortisol direct, then acth, but either way it's meant to result in cortisol being lowered. I feel more jittery as the day goes on, like I'm hyperactive, my ravenous appetite hasn't happened today, my usual insanely intense sweating wasn't bad this morning, but it creeping back as the day goes on.

What are the reasons behind all of your adrenal testing/ investigations? Does any bloodwork or symptoms give them suspicion of this? Have you ever head of congenital adrenal hyperplasia? That causes adrenal probs, im having that looked into aswell, it can cause adrenal crisis's but wouldn't neccesarily show up as low cortisol in blood tests etc because of a defect in an enzyme. (Something along those lines, sorry I'm not the best with words or explaining myself clearly)

SmallBlueThing profile image
SmallBlueThing in reply to ChristinaT

I figured the dexamethasone acts as fake cortisol so if we have a system out of control pumping out the real stuff, we get a high reading when tested, rather than the body reducing (suppressing) its production. So, the dexamethasone causes the body to suppress cortisol production if the control system (pituitary) and means of production (adrenals) are working correctly. Hope that's correct!

What are the reasons...? I noticed a sudden dry mouth after tiny increases in stress such as an increase in walking speed or responding in a conversation. I was on "watch & wait" for my thyroid, and had almost gone hyper, having been untreated subclinical hypo. Then my blood pressure was found to be through the roof (GP had never tested it) and the hospital tests showed my TSH in proper hypo territory with a note that my GP "might want to look into it".

My blood pressure remains high and labile (variable) on treatment. The endocrine causes are rare so the medics have used their Occam's razor and eventually dismissed white coat effect and non-compliance with drug-taking. Thanks to online access I can see low serum potassium and calcium in tests over several years, yet my GP still says they don't matter when they crop up. If things ever "blow up" with that relationship, I'll point to a set of results from before I had online access which were almost all out of range, yet nothing was done.

From en.wikipedia.org/wiki/Dexam... abdominal distension is listed as an adverse effect.

ChristinaT profile image
ChristinaT in reply to SmallBlueThing

Ah yes that's a brilliant explanation of it thank you. I'm a bit worried about my test because even tho I think it's highly likely I have cushings, my saliva tests show my cortisol is low normal in the morning. I Awake of an evening until 4/5 then I get sleepy. I'm just curious to know how they conclude its high accuracy, when I think a lot of cushi's are in the same boat. (Maybe I should stop trying to understand the technical stuff 😂)

My god why do they not think your potassium and calcium aren't important?!?!? It's just a piece of the puzzle. Ive had a few indicators come back out of range, ive queried it and they didn't seem to be bothered about it. Low and high blood sugar being one of them. I also notice my potassium stays at the very low end of the scale, and has occasionally swung the other way.

Ahh okay so you unfortunately have suffered a side effect of the dexamethasone.😞

I think your GP will find that these things do matter if you do indeed get diagnosed with cushi's!!(I hope you don't ofcourse)

SmallBlueThing profile image
SmallBlueThing in reply to ChristinaT

I asked if I should try and reset my sleeping pattern before the test but decided it was unlikely to happen so booked the first available test. I imagine the level to "fail" takes Cushi sleep patterns into account. When I was sleeping a bit more normally but with undertreated hypo, I would wake with a start. I guess my cortisol production was running at full steam.

Interesting that humanbean's link below says the test is used when there's low clinical suspicion. Maybe I need to be aware of the precision of medical language and interpret "clinical" as "outward signs"? (in my case, central obesity).

Thankfully, my low potassium swung the argument when a head honcho wanted to start me on a diuretic, most of which cause a loss of potassium!

The electrolyte imbalance all adds to the fatigue due to the problem they acknowledge.

ChristinaT profile image
ChristinaT in reply to SmallBlueThing

Do you find though that you feel awful when you have to do these tests and you sleep pattern is still not the universal norm?

It messes me up big time, I can barely get out of bed from having 1-2 hours sleep beforehand and weirdly my cortisol level is okay at that time. It's when it rises over the course of the day I feel more alert (though I wouldn't say better because I feel horrendous all of the time)

I haven't read the link human bean has posted yet, (I am going to tomorrow) but yeah you're right it's probably something we could both be doing with swatting up on really considering our predicaments.

I keep seeing that the 24 hot urine test is definitely one to do, even before dexamethasone suppression. That's my next move, I have a sneaking suspicion it will be more accurate for some reason (for me personally).

Oh gosh, what a careless thing to do, (prescribing that when your potassium was low) 🙈. It's a good job on you're on the ball with all of this.

I seem to not be able to tolerate potassium foods weirdly even though mine is at the lower end of the range usually. It's all very confusing. I experience symptoms on opposite ends of the scale simultaneously sometimes. When really bad my body temp goes very low, but I am hot and sweating buckets, like drenched in sweat all the time. It's so confusing. I'm getting a really bad pain behind my right eye socket and at the side of my head too (like a pressure pain) im not sure if that had anything to do with all of this either .......

SmallBlueThing profile image
SmallBlueThing in reply to ChristinaT

I usually manage about four hours' sleep before an appointment, and that means a trip to town which isn't a frequent occurrence for me, so I'm usually fairly energized, but exhausted after.

High cortisol reduces potassium and I found a discussion between medical students about the calcium: it blocks intestinal absorption; increases parathyroid hormone secretion; and increases losses in the urine.

Hoping things improve for you!

ChristinaT profile image
ChristinaT in reply to SmallBlueThing

It would definitely seem that's an/the indicator for you re,low potassium. I hope for your sake you don't have cushings but I do hope you're able to get yourself diagnosed and treated (whatever your medical issue is)

Please keep me posted with how you're getting on with all of this (that's ofcourse if you don't mind)

SmallBlueThing profile image
SmallBlueThing in reply to ChristinaT

The test came back normal, same for potassium.

Bearing in mind what's written above about cortisol reducing potassium, I wonder if I have Cyclic Cushing's, as my potassium was under-range when tested six weeks before, and several times before that.

My sleep's been disturbed since the test, maybe due to NDT. I'm back on Levo before a test, and after five days can feel crashes coming on and today had a temp of 35.4C, though didn't feel too chilly. Currently 36.4C when I'd expect 37C at this time.

I wonder if waking early on the day of the test allowed time for my system to "burn off" the cortisol?

ChristinaT profile image
ChristinaT in reply to SmallBlueThing

Hey. Thanks for getting back to me 😀. Right okay, so what is going to happen from here with regards to that then? Any further testing?

You know you could be right, Ive been reading up on a lot of stuff re; cushings and there are lots of accounts of people with cyclic cushings. Though tbh, you could probably do with a 24 urine test just to check? And maybe a few of them if they will allow you to do this. I think it definitely shouldn't be ruled out still, at least the 24 hour urine test would include your cortisol levels over the course of the day. There is also a saliva test aswell (I think they measure it twice over 24 hours)

If it's niggling away at you still then you could ask for further testing? Ive read up people passing the 'tests' and they still had cushings. (And not cyclic)

Low potassium is an indicator though, I mean I guess there's lots of things which could cause or attribute to low potassium, but it is definitely relevant to cushings.

Also it can mean different things with the dexamethasone test. Apparently someone could have cushings disease and not syndrome. I can't remember exactly which way around it is, but CS and CD tend to suppress at different dosages of the dexamethasone test (ie, low dose/high dose).

And it could be possible that waking up early altered your cortisol pattern. Don't forget your having to get up do this tests when they ask. I had a feeling it would be the same for me too, though I haven't received my results yet.

SmallBlueThing profile image
SmallBlueThing in reply to ChristinaT

I had to ask for the test result when it wasn't included in the consultant's letter. I don't know whether it was a case of "it's normal, so patient doesn't need to know." Not knowing may have affected my state of mind and sleep.

I wonder if I should write and volunteer/ask for 24 hour urine, which I would've preferred -- why take a pill if you don't need to? The logistics of a 24 hour test aren't a problem for me.

This cyclic nature of things: I had a rare day with normal blood pressure, between two "normal for me" days, which were about 30 mmHg higher. An interesting part of the puzzle, for anyone who cares to investigate.

ChristinaT profile image
ChristinaT in reply to SmallBlueThing

If you feel it's neccesary then do it, leave no stone unturned, plus I think it's a fairly cheap test costwise, so it's not as if it's a huge thing for them but it could mean everything to you. I think usually they would do a urine test first, (whether they're meant to I don't know) but according to the endo/cushings info on it, it's states there are four tests for investigation. (Low dose dexamethasone being one).

Apprently the cortisol levels in cushings are higher than normal levels in the morning, but I know if my saliva test is anything to go by then mine are actually low normal first thing, they then increase rapidly about 11am and remain raised. (Bearing in mind that's just based on a private saliva test I've had and I don't think the nhs would take that into consideration unless they allowed me to do a saliva test via them).

I think a urine test would give a clearer picture of your cortisol levels, but that is just my opinion. (From someone who isn't medically trained).

For all we know a urine test may show your levels are high and if indeed that was/is the case then they would have to investigate further. Dexamethasone is accurate I beleive but even online Endo's state there is still the possibility of having cushings, whether is syndrome or disease depending on where exactly the problem lies.

Yes your right, I think from day to day your blood pressure may change and has done already, given all that it literally depends on how you feel on the day which could affect everything. I'm going to really push for a urine test (will try my best anyway, depending on results from DM test), I don't think I will feel completely satisfied or certain unless I have one. If you don't feel happy with just having the DM test then yes ask for the urine test. X

SmallBlueThing profile image
SmallBlueThing in reply to ChristinaT

I was given no leaflet with the DST, but the pharmacist (plus instructions on the box) told me to take with, or just after food or a meal. I was feeling pretty energized, and ate rather a lot! Now I've read that 10 hours should be left between eating and the blood draw, and it would've been about seven hours for me.

When I had the test, I was taking NDT. I'm on Levo for 10 days before a conventional TSH test and, as mentioned, my temperature is struggling now I'm getting no T3 help. I stopped NDT for five days before the last test, which also showed low potassium. So, I think my cortisol rises in response to the low body temp, and pushes down my potassium and calcium.

ChristinaT profile image
ChristinaT in reply to SmallBlueThing

It probably is indeed the case. It all seems connected one way or another by what you describe.

I asked my endo if eating during or around. Taking the tablet was allowed and he said yes it didn't make a difference at all. Just carry on as normal. I have an unusually increased appetite anyway. Again whether or not eating would possibly affect the test, I don't know, we can only theorise given how we feel and react to it all.

I still can't help but think the Dexamethasone test on its own is enough to confirm or rule out cushings. I'm not in denial about it but surely cortisol levels will fluctuate from person to person even if they're own levels are abnormal. How do you feel about the result? And where does that leave you now in terms of the next step? X

ChristinaT profile image
ChristinaT in reply to ChristinaT

The body temp issue is interesting tho, and seems definitive of something, clearly something is affecting you for your temp to be so low or to fluctuate. It leaves a big question mark over your low potassium doesn't it. Especially when thyroid and adrenal/pituitaryissues are so interlinked with each other.

SmallBlueThing profile image
SmallBlueThing in reply to ChristinaT

The Dexamethasone can cause queasiness, hence the advice about having something else in the stomach.

Did you mean to wite: "I still can't help but think the Dexamethasone test on its own is not enough to confirm or rule out cushings."?

If my potassium is tested again this time and is low, it would be a further reason to request a 24 hour urine test, but then I'd need to delay returning to NDT until the test is completed. Then again, if NDT cures me of pseudo Cushing's that's better than a further delay before possibly being "messed around with" with an unnecessary treatment plan.

Some people say their temperature never recovers, even on NDT. I've had miserable out of the blue days during previous summers with body temp below 35C but it's been 36.6C at the surgery and of no concern. Adding T3 and using NDT has helped, but it takes a wee while to fill all the nooks and crannies with T3 to allow the body to have its demands met.

NDT hasn't normalized my blood pressure, and that was the reason for the suppression test: to see if there's a secondary cause for my hypertension. So, that rather decides the matter, and I think I should ask for the 24 hr test.

ChristinaT profile image
ChristinaT in reply to SmallBlueThing

Yes sorry that was what I meant. My apologies, I lose my trail of thought frequently and tend to write in broken biscuits or go off on a tangent about stuff. I don't mean to, but yes I do Think the dexamethasone test is not necessarily a confirmation on its own. Maybe in some cases or even most but not all. I think they should at least allow 2 tests and compare results, just because it can be tricky to diagnose.

I can understand what you mean regarding the NDT, if it's making you better then I can see why you wouldn't want to refrain from taking it, even for a urine test. You're still left with the low potassium issue. Low potassium can be related to taking high doses of B12 and also kidney fuction, but the emphasis does seem to lie with the possibility of cushings. I don't think a urine test would do any harm whatsoever especially if you're not being provided with a reason as to why it goes low periodically, at least up to this point anyway. Low potassium in itself can cause some quite unpleasant symptoms. If you do request for a urine test, please let me know how you get on if you don't mind. X

humanbean profile image
humanbean

If you want info on how testing should be carried out (when done properly), see this link :

imperialendo.co.uk/Bible201...

Look at the table of contents, and click on "Suspected Cushing's Disease" on Page 24. You might also be interested in "adrenal Investigations" on Page 66, also Page 73. In fact it is probably easier to just search for the word Cushing. :)

SmallBlueThing profile image
SmallBlueThing in reply to humanbean

Thanks.

OVERNIGHT DEXAMETHASONE SUPPRESSION TEST

INDICATION

Initial screening test for Cushing's syndrome in a patient with a low clinical suspicion of Cushing‟s if it is difficult to admit patient for a standard (48h) low-dose dexamethasone suppression test.

ChristinaT profile image
ChristinaT in reply to humanbean

Thank you so much for this information you've provided. I will look into this tomorrow. It's all really valuable to me, I really appreciate it 👍

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