Adrenal Insufficiency
Adrenal insufficiency means the adrenal glands don't produce enough cortisol, classified as primary, secondary, or glucocorticoid-induced (the most common type overall, affecting 1-3% of adults on chronic steroids), per the Endocrine Society 2016 guideline and the 2024 joint ESE-Endocrine Society glucocorticoid-induced guideline.
Symptoms
Fatigue, weight loss, low blood pressure, and salt craving are common; hyperpigmentation is specific to primary adrenal insufficiency (Addison's disease), where the pituitary compensates by overproducing ACTH.
Causes and risk
Autoimmune destruction causes most primary cases; pituitary disorders cause secondary disease; long-term steroid use (for other conditions) causing suppression of the body's own cortisol production is the most common cause overall.
How it is evaluated
The 250 mcg cosyntropin stimulation test (peak cortisol under 18 mcg/dL confirms the diagnosis) plus morning cortisol and ACTH to distinguish the subtype.
Treatment
Hydrocortisone (15-25 mg/day) or prednisone (3-5 mg/day) replaces the missing cortisol; fludrocortisone is added for primary disease specifically, to replace aldosterone too. Sick-day rules -- doubling or tripling the oral dose during illness, with injectable hydrocortisone for vomiting or severe illness -- are essential and worth a dedicated conversation with your provider.
When to seek care
Adrenal crisis -- severe weakness, vomiting, abdominal pain, low blood pressure, and confusion -- is a life-threatening emergency. Patients on chronic steroids or with known adrenal insufficiency should carry an emergency hydrocortisone injection and use it before heading to the ER if symptoms are severe.