In medicine, adrenal insufficiency (or "hypocortisolism") is the inability of the adrenal gland to produce adequate amounts of cortisol in response to stress. See also: Adrenal Fatigue or Hypoadrenia.

Causes can include:

* Acute adrenal insufficiency
o Addison's disease (autoimmune adrenalitis)
o Septic shock
o Waterhouse-Friderichsen syndrome
o Addisonian crisis in case of:
+ Discontinuing corticosteroid therapy without tapering the dosage
+ Surgery, illness or any other form of stress in patients with long-term corticosteroid therapy

* Chronic adrenal insufficiency
o Addison's disease
o Congenital Adrenal Hyperplasia
o antiphospholipid syndrome
o haemochromatosis