How would you diagnose Primary Adrenal Insufficiency in this patient?
Random cortisol:
<100 nanomol/L = Adrenal insufficiency is highly likely (if the patient is not on oral or inhaled steroids).
100-400 nanomol/L = Further investigation is required.
>400 nanomol/L = Adrenal insufficiency is unlikely (diagnosis cannot be entirely excluded if the patient is acutely unwell at the time since cortisol values may increase due to severe illness).
Short synacthen test/ACTH stimulation test:
Take a basal sample for cortisol
Give 250 microgrammes Synacthen IV
Samples for cortisol are taken at 30 mins and 60 mins
In healthy individuals, the basal plasma cortisol should exceed 170nmol per litre and rise to at least 500nmol per litre.
The hypoadrenal patient is unable to raise their serum cortisol in response to synacthen1.
During this patient’s acute illness, a random cortisol was 24 nmol/l
