Adrenal Insufficiency

Today, we discussed the case of an elderly man with DM, adrenal insufficiency, and hypothyroidism who presented with altered mental status. We discussed the classifications of adrenal insufficiency, and how to diagnose AI in an inpatient setting!



  • The use of AM Cortisol level  to diagnose adrenal insufficiency should generally be reserved for the outpatient setting. For hospitalized patients, ACTH stimulation test is much more reliable and should be preferentially used.
  • Use the absolute value of post-stimulation cortisol (target 18-20 as the appropriate response to stimulation) to diagnose adrenal insufficiency, rather than the delta (or the change) in serum cortisol levels from stimulation


More on Adrenal Insufficiency

  • PRIMARY adrenal insufficiency
    • This is the failure of the adrenal gland to produce cortisol
    • Causes à Addison’s disease (most common in the US), infiltrative processes (such as TB), hemorrhage, toxins
    • Acute adrenal crisis versus chronic adrenal crisis
      • Acute: hypotension/shock, abdominal/flank/back pain, lethargy, fever, anorexia, confusion
      • Chronic adrenal insufficiency: hyperpigmentation (due to increased ACTH secretion), GI symptoms, weight loss
  • SECONDARY adrenal insufficiency
    • This is the failure of the pituitary to produce ACTH
    • Causes à Panhypopituitarism, pituitary lesions/surgeries, TBI, drugs (e.g. high dose progestins)
    • May also see loss of other anterior pituitary hormones
    • In contrast to primary adrenal insufficiency, DO NOT see:
      • Hyperpigmentation (since ACTH secretion is not increased)
      • Hyperkalemia (since you still have presence of aldosterone)
  • TERTIARY adrenal insufficiency
    • This is the failure of the hypothalamus to secrete CRH
    • Causes: Abrupt cessation of high-dose glucocorticoid therapy, cured Cushing’s syndrome (status post removal of ACTH-secreting or cortisol-secreting tumor)




One thought on “Adrenal Insufficiency”

  1. Another cause of secondary AI is Isolated ACTH deficiency….my son has this very rare disorder. Diagnosed at birth by chance luckily…had maternal markers in pregnancy of low estriol. Would love to get the word out on this connection as I discovered it by my own research—Dr’s don’t seem to be aware of this connection, which means some babies may not be diagnosed early enough to sustain life.


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