Summary
Highlights
The video introduces Cushing syndrome and Cushing's disease as types of hypercortisolism. Cushing syndrome is a primary hypercortisolism, involving a problem with the adrenal gland, while Cushing's disease is a secondary hypercortisolism, related to the pituitary gland.
Cushing syndrome involves hyperfunctioning of the adrenal cortex, leading to increased cortisol release. This can be due to adrenal adenomas (most common) or exogenous steroid use. Exogenous steroids mimic cortisol's effects, often used chronically for autoimmune diseases or transplants.
Cushing's disease is a secondary hypercortisolism where the pituitary gland pumps out excessive ACTH, stimulating the adrenal cortex to produce more cortisol. This is often caused by a pituitary microadenoma. Ectopic ACTH production, often from tumors like small cell lung cancer, can also cause increased cortisol.
Both Cushing's syndrome and disease present with fat redistribution (buffalo hump, moon face, truncal obesity) due to lipolysis and fat redistribution. Skin atrophy and striae occur due to proteolysis, breaking down collagen. Hyperpigmentation is specific to Cushing's disease due to increased melanocyte-stimulating hormone. Masculinization (hirsutism, increased libido) can also occur in females with Cushing's disease.
Long-term complications include secondary hypertension (due to increased alpha-1 receptor sensitivity and sodium/water retention), diabetes mellitus (due to increased blood glucose levels and insulin resistance), and osteoporosis (due to collagen breakdown). Immunosuppression can lead to fungal infections and other opportunistic infections.
Diagnosis involves confirming high cortisol levels through 24-hour urinary cortisol tests, low-dose dexamethasone suppression tests, and late-night salivary cortisol tests. ACTH levels help differentiate between Cushing's syndrome (low ACTH) and Cushing's disease (high ACTH). CRH stimulation tests and high-dose dexamethasone suppression tests further pinpoint the source.
Treatment for Cushing syndrome involves tapering steroids or suppressing adrenal adenomas with ketoconazole, followed by surgical removal (adrenalectomy). Cushing's disease treatment includes ketoconazole to reduce cortisol and transsphenoidal resection of pituitary microadenomas. Small cell lung cancer causing ectopic ACTH requires chemotherapy and radiation.