Corticosteroid withdrawal
Secondary adrenal insufficiency - deficiency of ACTH (produced by the pituitary gland)
Tertiary adrenal insufficiency - deficiency of CRH (produced by the hypothalamus)
Addison's disease
Corticosteroid withdrawal
Sheehan's syndrome
Secondary adrenal insufficiency - deficiency of ACTH 
Cushing's syndrome
Tertiary adrenal insufficiency - deficiency of CRH 
Wilson's disease
Zollinger-Ellison syndrome