<prompt> Most common cause of adrenal insufficiency isHemorrhageTuberculosisAutoimmunityNone  <response>: C Autoimmunity Primary adrenal insufficiency is most commonly caused by autoimmune adrenalitis. Isolated autoimmune adrenalitis accounts for 30-40, whereas 60-70 develop adrenal insufficiency as a part of autoimmune polyglandular syndromes APS. APS1, also termed APECED autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy, is the underlying cause in 10 of patients affected by APS Classification of Adrenal insufficiency Primary Adrenal Insufficiency: Anatomic destruction of gland chronic or acute Idiopathic atrophy autoimmune, adrenoleukodystrophy Surgical removal Infection tuberculous, fungal, viral--especially in AIDS patients Hemorrhage Invasion: metastatic Metabolic failure in hormone production Congenital adrenal hyperplasia Enzyme inhibitors metyrapone, ketoconazole, aminoglutethimide Cytotoxic agents mitotane ACTH-blocking antibodies Mutation in ACTH receptor gene Adrenal hypoplasia congenita Secondary adrenal Insuffiency: Hypopituitarism due to hypothalamic-pituitary disease Suppression of hypothalamic-pituitary axis By exogenous steroid, by endogenous steroid from tumor 