Brief Answer:
Depends on symptoms

Detailed Answer:
Good day Ms XXXXXXX

Welcome to health care magic. Thank you for asking the question. The cortisol level mentioned is towards the higher side. Again, cortisol levels can go up based on a number of factors including Stress, alcohol intake or if you are depressed. Acute illnesses are another reason why the cortisol levels go up. Cushings syndrome is another cause of abnormally high cortisol levels. I presume your doctor ordered cortisol rest to rule out cushings syndrome.
ACTH is produced in pituitary gland which stimulate the adrenal gland to produce cortisol. When cortisol levels go up for any reason ACTH levels should drop. In your case, the ACTH levels have dropped. This indicates that probably your adrenal gland is secreting excess cortisol independent of pituitary stimulation by ACTH. In some cases, pituitary ( or an ectopic source) make excess ACTH which further stimulates adrenal gland to produce cortisol. In this case,ACTH remains elevated despite high cortisol. This second situation is unlikely the cause in your case because ACTH levels have dropped.

In a normal person, ,ACTH levels are lowest at midnight avd highest at early mornings. In cushings syndrome this pattern may be altered.

However I must say that a raised random cortisol is not a confirmatory test for Cushings syndrome. You now need a suppression test ( dexamthasone suppression test ) to evaluate further.

What time of the day was cortisol and ACTH collected. Was the ACTH sample stored in cold syringe or was the sample frozen immediately? .What symptoms do you have? are you using any Hormonal pills for regulating periods or for contraception? ( this can change cortisol levels too).
All these factors matters. You need an endocrinology evaluation and after examination ,,they should do further tests.
Regards
Binu

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Brief Answer:
Next steps

Detailed Answer:
Thank you for the reply.
I wonder if your doctor did an Estradiol ( E2) and FSH test? If FSH is high, that itself will cause flushing etc. In your case, since you have received radiotherapy near the pituitary area, the FSH is likely to be low.

The next step in your case is to do a Dexamethasone suppression test and /or a 24 hour urinary free cortisol test. If they too are positive, then we need to do a midnight cortisol and ACTH test and imaging of pituitary or adrenals based on the results of above tests. I am sure that your endocrinologist will arrange these tests. In the interim, please be relaxed.

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