5th April 2024

Pathophysiology

Cushing’s syndrome is caused by an excess of glucocorticoid within the body. The most common cause is exogenous administration in patients on long term steroid tablets but less commonly, the syndrome can be due to excess ACTH or cortisol release from tumours.

Cushing’s disease is the most common non-iatrogenic cause of Cushing’s syndrome. It is caused by an ACTH secreting pituitary tumour which leads to bilateral adrenal hyperplasia. Certain cancers, including small cell lung cancers and carcinoid tumours can also secrete ACTH. In rare cases, cortisol is secreted directly from adrenal adenomas.

Clinical manifestations

Cushing’s syndrome affects multiple body systems shown below in the image below.

Image Source: Wikimedia Commons (2015). Cushing’s Syndrome, Licensed under a creative commons licence. Available for free at: https://en.wikipedia.org/wiki/Cushing%27s_syndrome (Accessed: 6 February 2024).