There’s a textbook for everything in medical school. Heart, lungs, brain, skin, everything has a specialty. In endocrine textbooks, the adrenal gland tend to have a relatively small chapter. In their defense, there’s a lot of hormones, and most common endocrine disorders are related to thyroid or diabetes. Diabetes is so common in the United States especially, that it is the most prevalent specialty within endocrinology.
Diseases of the hypothalamic-pituitary-adrenal axis are incredibly rare by comparison. Addison’s disease, the autoimmune destruction of the adrenal glands, is quite rare. It’s commonly referred to as primary adrenal insufficiency.
Increasingly common, however, is secondary adrenal insufficiency (SAI). This is a disorder of the adrenal glands caused by a disfunctional pituitary gland.
One reason for the increased prevalence of SAI is the abundance of steroid treatment for other illnesses, from allergies to lupus. Long term use of steroids has a risk of disrupting the HPA axis, and tricking the pituitary gland into believing it doesn’t need to produce adrenocorticotropic hormone (ACTH), the precursor to cortisol.
A result of the pituitary gland believing it’s services are no longer necessary is often that it completely forgets how to work, and as a result, it no longer produces ACTH, which is necessary for cortisol. If the ACTH is missing, the adrenal glands don’t think they need to make cortisol, so they don’t.
When a person stops using corticosteroids for their other illness, sometimes they find that they experience profound fatigue, low blood pressure, low blood glucose, and many other signs and symptoms of adrenal insufficiency.
It’s essential at this point that a person meet with their doctor to investigate potential SAI.
Keep in mind, SAI isn’t only caused by steroid use. It can be due to a pituitary tumor, pituitary damage, or sometimes an unknown cause.
Testing for SAI is tricky, because sometimes the adrenal gland still work, if they’re given the opportunity.
Standard testing, as laid out by Cleveland Clinic, has a pretty clear path to diagnosis. However, SAI isn’t always clear cut.
Sometimes a patient will have a low baseline cortisol, and despite that baseline, when given an extra large dose of synthetic ACTH, or cosyntropin, the adrenal glands respond appropriately.
That could look something like:
Cortisol baseline: 4.5
Cortisol 30 minutes: 18
Cortisol 60 minutes: 23
ACTH baseline: 5
If a patient has that inappropriately low cortisol as well as ACTH, then further pituitary function needs to be assessed.
The reality is, however, that many endocrinologists assume that any reasonable response of the adrenal glands rules out SAI.
Cortisol baseline: 3.4
Cortisol 30 minutes: 12
Cortisol 60 minutes: 16.8
Many doctors incorrectly assume that because the adrenal response is to more than double (or sometimes greater than 10 more than baseline) the cortisol response is accurate and they refuse to diagnose a patient.
There’s a clear cut set of diagnostic rules, and some old information floating around that leads these doctors to ignore clear diagnostic criteria, leaving many patients at continued risk of adrenal crisis and death.
When a patient finds themselves in a position where it seems like their doctor doesn’t understand, or that the pieces don’t quite add up, it becomes essential that they continue to pursue more testing and an eventual diagnosis. Your life very well could depend on it!