Which blood tests for pituitary function?

[OllyTojo]

Hello everyone

Does anyone know which blood tests to ask for to test my pituitary function? New GP has said he will run tests but didn't know which ones. My blood test is this Thursday.

Some background history: in 2015, when in Thailand, I became seriously ill. Main hospital in the north ran lots and lots of tests on me. Ended up in endocrinology department, lots more tests. Results were pituitary (mri showed mild bulge anterior border left but no lesions) - causing adrenal insufficiency - causing hypothyroidism. Low growth hormone. Was put on steroids and euthyrox in Thailand. Felt much better. I had been taking cytomel for years at this point. Consistently blood tests over the years have shown t3 OK or high (on cytomel), tsh very low 0.0 something and t4 very low. No matter how much t4 they put me on, it never goes above about 14.

When I got back to the UK, they refused to acknowledge any of it as it was from Thailand. My GP just said, I don't think you do have a pituitary problem!

I have read on here that low tsh, high or normal t3 and low t4 points to pituitary. I am not on steroids any more - caused stomach bleeding (sorry for details).

Does anyone know which blood tests would be useful to ask for for my blood test on Thursday?

Many thanks

[SeasideSusie Remembering]

OllyTojo

I have read on here that low tsh, high or normal t3 and low t4 points to pituitary

That's not quite right where T3 is concerned.

Whilst looking for a diagnosis and before medication, Central Hypothyroidism can be suggested by a TSH level that is low, normal or minimally elevated together with low/below range FT4. FT3 doesn't necessarily come into it as the body will do everything possible to push out T3 as this is the active hormone that every cell in the body needs. If FT3 is also low along with below range FT4 then that would very likely be more evidence. Secondary Hypothyroidism is where the pituitary is at fault (Tertiary Hypothyroidism is where the hypothyalamus is at fault).

If your GP doesn't know which test to order, why doesn't he contact the lab which does the tests?

The fact that you have been/are on thyroid medication may very well be a problem in diagnosis.

[SlowDragon Administrator]

On almost any dose of T3 TSH is almost always suppressed So that wouldn’t confirm pituitary issue

You need MRI to see if pituitary shows physical damage

Plus there’s various other tests that endocrinologist can perform

Pituitary blood test

Adrenal testing too

24 hour urine test for cortisol

ACTH test

Etc

[OllyTojo in reply to SlowDragon]

Thank you SlowDragon. I had all those tests in Thailand and all pointed to pituitary. ACTH. I have had lots of adrenal tests done privately over the years and cortisol and it shows in exhaustion stage. I also had cat scan last year for another issue which showed enlarged adrenal gland. I am thinking maybe I should leave it all alone as I'm not feeling too bad at the minute.

[SlowDragon Administrator in reply to OllyTojo]

NHS will rarely accept any tests done elsewhere 😟

[OllyTojo in reply to SlowDragon]

Also MRI did show abnormal pituitary - mild bulge to anterior border. I was told to keep checking my peripheral vision to check for any changes, loss of sight. It was very scary.

[jimh111]

Pituitary problem (central or secondary hypothyroidism) presents with low or low normal fT3 and fT4 with a non-elevated TSH. Unlike primary hypothyroidism (failed thyroid) fT3 levels are not maintained. This can only really be diagnosed when you have not been taking thyroid hormone for some time. Other pituitary hormones will also be low. It's really something for an endocrinologist rather than a GP. Doctors in reputable hospitals in Thailand are just as good as UK doctors.

If thyroid blood tests point to central hypothyroidism then an endocrinologist would have to investigate further. Your blood test results from Thailand would be most useful, so get hold of a copy if you don't have and perhaps post here.

[OllyTojo in reply to jimh111]

I will dig out all the results and see if I can get them converted online

[SeasideSusie Remembering in reply to OllyTojo]

OllyTojo

I will dig out all the results and see if I can get them converted online

The results are in different measurements than those used here so GP said unable to read them

As far as thyroid tests are concerned it doesn't matter what unit of measurement it is, as long as the reference range is with the result then that's enough, no need to convert any of them. If your GP can't see where a result lies within the reference range then he's in the wrong profession, or he's wriggling his way out of using those results.

[OllyTojo]

Thank you jimh111. I do have copies of all test results from Thailand. They tested all hormones and did ACTH test etc. growth hormone was low. The results are in different measurements than those used here so GP said unable to read them. I have done many saliva cortisol tests privately and Dutch profile of all hormones. They are all pitifully low. Cortisol shows exhaustion stage.

[jimh111 in reply to OllyTojo]

I would get your GP to refer you to an endocrinologist. A doctor should not attempt to act outside their expertise and so are obliged to refer.

[helvella]

The website Thyroid Manager - which has been going for years and has lots of information - has a diagram indicating what to look for when thyroid tests have strange results. One leg has hypopituitary - for which they identify:

LH - Luteinising hormone

FSH - Follicle stimulating hormone

PRL - Prolactin

Testosterone

Estrogen

Cortisol

Gonadotropin-releasing hormone

Insulin tolerance test (ITT)

TRH Throtropin releasing hormone

thyroidmanager.org/wp-conte...

Flowchart to interpret strange thyroid test results

[OllyTojo in reply to helvella]

Thank you helvella. Looking at the chart, It really does point to hypopituitary. Results of all my tests going back to 1990 have flagged all these hormones up. I will go through and make an easy to read record of my results for endo and gp. I am due to speak to endo at the beginning of March. This is the first time in all those years I have felt well enough to look into all of this. This is such a helpful site. Thank you so much for your part in it. Invaluable

[helvella in reply to OllyTojo]

You might find my recent post of some use:

Thyroid Disease Manager and Endotext

healthunlocked.com/thyroidu...

Specifically, there is a whole section on pituitary. Quite some reading if you go through all of it! Hopefully you will be able to locate the interesting bits.

Pituitary Disease and Neuroendocrinology

ncbi.nlm.nih.gov/books/NBK2...

[humanbean]

I can't help you directly, but you might find this document useful...

It is a document describing every test that a normal UK hospital endocrinology department might do for various conditions, and it is called the "endocrine bible".

imperialendo.co.uk/Bible201...

It tells you why a particular test might be carried out, how to prepare, timing, and interpretation of results.

Bear in mind that different hospitals will have their own reference ranges.

[OllyTojo in reply to humanbean]

Thank you. I'll have a good read of that tomorrow. Very helpful