Adrenal Insufficiency Causes and Clinical Significance

Primary Adrenal Insufficiency

Primary adrenal insufficiency occurs when the adrenal gland itself is destroyed or dysfunctional, resulting in deficiency of both cortisol and aldosterone, affecting approximately 100 times fewer patients than iatrogenic causes 1, 2
Autoimmune adrenal destruction (Addison's disease) is the most common cause of primary adrenal insufficiency in Western populations, accounting for approximately 85% of cases, characterized by the presence of autoantibodies in most patients 3
Congenital adrenal hyperplasia, particularly a specific enzyme deficiency, is the most common inherited cause, occurring in 1 in 15,000 live births 1

Secondary adrenal insufficiency results from pituitary ACTH deficiency, with cortisol deficiency but preserved aldosterone production, since the renin-angiotensin system remains intact 1, 4
Developmental disorders of the hypothalamus and pituitary, including mutations in essential transcription factors causing combined pituitary hormone deficiencies, can cause secondary adrenal insufficiency in children 1
Brain tumors and their treatment can affect approximately 1 in 10,000 children, leading to secondary adrenal insufficiency 1

Tertiary adrenal insufficiency is the most common cause of adrenal insufficiency in clinical practice, affecting approximately 7 in 1,000 people, roughly 100 times more prevalent than intrinsic adrenal or pituitary disease 1, 2, 4
Any route of glucocorticoid administration can suppress the hypothalamic-pituitary-adrenal axis: oral, inhaled, topical, intranasal, and intra-articular 1, 2, 4
Inhaled corticosteroids can cause HPA axis suppression in a dose-dependent manner 1, 2
Children receiving glucocorticoid treatment for various conditions represent a significant proportion of adrenal insufficiency cases 1, 2

Patients with adrenal insufficiency face significantly elevated mortality risk, with risk ratios of 2.19 for men and 2.86 for women, primarily from cardiovascular, infectious, and malignant diseases 1, 2, 4
Adrenal crises occur at a rate of 6-8 episodes per 100 patient-years and carry substantial mortality risk if untreated, with 8.6% of patients reporting previous crises caused by inadequate glucocorticoid coverage during hospitalization or surgery 1, 2, 4