Note: I don't and have never taken any other drugs, and no illegal stuff either, ever. So it's not likely that low ACTH and Cortisol are due to me taking something improperly. Thyroid pills and low Cort are somehow related.
I wasn't implying the inappropriate use of drugs but asking if you can think of some exposure in your environment that could be interesting with the HPA axis. This could be a medication you take, a supplement, a toxin exposure ( solvent, mold, food, water etc..) that varies day to day leading to varied cortisol regulation. Cortisol is regulated by the HPA axis based on the circadian rhythm, cortisol levels and stress.
But other things can interfere such as the drugs I mentioned. You are taking Thyroid medication and Testosterone which are hormones in closely related systems ( HPT and HPG axis). The Hypothalamus is at the base of the brain and is the gland that participates in the regulation of all of these hormones regulation. That makes me suspicious along with wondering if your Cortisol levels vary day to day suggesting some "external" interference with the HPA axis regulation.
The Pituitary produces ACTH in response to CRF being produced by the Hypothalamus. Based on your having seen low ACTH AND low Cortisol, that suggests its NOT your Adrenals but caused by the Pituitary or Hypothalamus.
If you tested your Cortisol and ACTH for an entire week at 8AM, you normally should not see a large variation unless there is some outside influence or significant stress ( an outside influence). If you do see a large variance, you would ask the question, what did you do differently that might be that outside influence.
For example, say you were painting your bedroom one day and saw the ACTH/Cort low the next morning. That would alert you that something in the paint such as a the a solvent exposure might be the problem. This is only an example to get you to think about what you did that might expose you to some outside interference to the HPA axis. It also explains why testing every day for a least a few days is crucial in determining whether your ACTH/Cort is fluctuating.
I have not taken Pred since May 2019 (today is Oct 22, 2019) . That was a 4 month cycle of Pred 10mg/1 d. After tapering off, I felt pretty normal for 3 months. Now 5 months later, I'm getting my old symptoms back. Interestingly, they are not as severe. I'm also not passing out (fatigue so severe I must stop what I'm doing and sleep) 5-6 times per day.
So now is the time to ask to get tested for multiple days. Just this comment suggests your HPA axis response is blunted and gradually your Cortisol production is declining.
I'm going to CC for an ACTH stim test this Friday. I suspect it will be normal. As anytime cort tested low, ACTH was also low.
Good. Is this being monitored by a Endocrinologist? Its too bad you can't check ACTH and Cortisol every day till Friday. Low ACTH suggests is secondary and not the Adrenals themselves. But does it vary or does it just slowly decline till you have symptoms? Have they done any scans such as an MRI to look for a tumor near your Hypothalamus or Pituitary?
Given you have problems with Thyroid ( HPT axis) and Testosterone ( HPG axis )also, I'd be very curious if there is some structural problem around your Hypothalamus. That's why I asked if they ever found the cause of the HPG axis problem ( low T)? Now you have a possible HPA axis problem. The "H" (Hypothalamus) seems a common denominator.
The list of testing is pretty epic. I'll note the oddball ones.
Cortisol 4.2 (lab range 6-22)
ACTH 7.2 (lab range 7-63) (note every time ACTH is tested, it's 10 or lower)
RNP Antibodies 7.6 (Lab range 0.0-0.9 AI) Flag H (subsequent test in CA did not exceed the lab threshold of 10.
Even though an Endocrinologist is the obvious specialist you need to focus on, you mentioned earlier the Thyroid problems might be autoimmune in nature. The positive ANA and RNP are suggestive a possible autoimmune disorder which also points at a Rheumatologist ( Autoimmune specialist) as another specialist.
My experience is that when two disparate specialists are suggested, it gets complicated and its easy to get lost between them. Specialists do better when its solidly in their camp rather than a mystery straddling both areas.
The thing is, I have high blood pressure, not low. And I'm no longer skinny. All due to utter lack of energy and needing to eat.
What I meant is when you got dizzy, you might have been an adrenal crisis. An adrenal crisis causes your blood pressure to drop suddenly and its dangerous. You could have high blood pressure most of the time but when your Cortisol is very low for some time, you enter an adrenal crisis, your blood pressure drops very low and you get dizzy and can faint or black out.
Do you have a desire for salt? Do you crave carbohydrates that are salty? Low Cortisol makes you crave salt which obviously will cause weight gain if its chips or other salty carbs. Do you ever have low back pain that doesn't seem to be your spine? That's another adrenal insufficiency indicator along with the salt craving.
If you get dizzy, sit down and check your blood pressure. If its very low, unusually low, that's dangerous and you should go to the ER and mention your adrenal insufficiency and have them do a Cortisol test.
I'm not sure where you live but you might consider getting a referral to the Mayo Clinic in Rochester so you can see an Endocrinologist, Rheumatologist and Infectious Disease specialist all together. They will do the appropriate MRI to make sure there is no physical cause to these problems and look for a infection cause. Are you aware of any chronic infections you might have like EBV?