ectopic ACTH
Last reviewed 06/2021
This is the production of adrenocorticotrophic hormone (ACTH) from a source other than the anterior part of the pituitary gland.
This phenomenon is usually associated with a small cell carcinoma of the bronchus. Less common causes include thymic tumours, pancreatic adenocarcinoma, bronchial carcinoid.
Presentation:
- Cushingoid features may be present if the tumour is slow growing
- features generally include:
- generalized muscle weakness
- mental abnormality
- oedema (fluid retention)
- diabetes
- skin hyperpigmentation
- hypokalaemic alkalosis
- although metastasis to the adrenals often occurs with bronchogenic carcinoma a hormonal deficiency due to replacement is very unusual
Investigation:
- no increased in steroid metabolites after metyrapone administration
- no suppression of cortisol levels after dexamethasone administration
Treatment:
- tumour resection or adrenalectomy
- medical management includes the use of drugs such as the adrenolytic mitotane and aminoglutethimide