Definition
- Cushing syndrome is the clinical state produced by hypersecretion of glucocorticoids (cortisol excess), first described by Harvey Cushing.
Etiology and Classification
- Cortisol excess is ACTH independent (adrenal tumour, or exogenous steroid) or ACTH dependent (pituitary ACTH-producing tumour, or ectopic ACTH/CRH-producing tumour, e.g. bronchogenic carcinoma).
- Cushing's disease refers specifically to the disease from an ACTH-producing pituitary tumour; Cushing's syndrome covers all causes of cortisol excess.
Causes of Cushing syndrome
Category
ACTH dependent
- Cause
- Pituitary ACTH-producing tumour; hypothalamo-pituitary dysfunction
ACTH dependent
- Cause
- Ectopic ACTH- or CRH-producing tumour (e.g. bronchogenic carcinoma)
ACTH independent
- Cause
- Adrenal tumour (adenoma or carcinoma)
ACTH independent
- Cause
- Adrenal macronodular hyperplasia
ACTH independent
- Cause
- Familial adrenal dysplasia (Carney syndrome)
ACTH independent
- Cause
- Prolonged, excess exogenous ACTH or cortisol (iatrogenic)