Cushing's Flashcards
Pt has a high 24-hour urine free cortisol and low ACTH levels. Is this Cushing’s syndrome or Cushing’s disease?
Cushing’s syndrome (caused by adrenal adenomas/ carcinomas, exogenous glucocorticoids)
Pt has a high 24-hr urine free cortisol and high ACTH levels. What could this be caused by? (2)
Cushing’s disease (pituitary adenoma)
Ectopic ACTH production
What is Cushing’s syndrome?
Excess cortisol not driven by ACTH secretion (loss of HPA feedback)
What is Cushing’s disease?
Excess cortisol driven by ACTH secretion - caused by pituitary adenoma (loss of HPA feedback)
What are the levels of cortisol throughout the day?
High in the morning
Low in the evening
What effect does cortisol have on the body in times of stress?
- Increase gluconeogenesis
- Increase proteolysis
- Increase lipolysis
How can exogenous cortisol cause Cushing’s? (5)
Causes -ve feedback on hypothalamus + pituitary Less CRH + ACTH produced Less cortisol produced BOTH adrenal glands atrophy Still high exogenous cortisol levels
How can endogenous cortisol cause Cushing’s? (3)
Benign pituitary adenoma + ectopic sources of ACTH releases too much ACTH and adrenal glands undergo hyperplasia so more cortisol produced
Adrenal adenomas/ carcinomas secrete cortisol, suppressing CRH + ACTH, causing atrophy of uninvolved adrenal gland.
What are the clinical presentations of Cushing’s? (13)
BAM CUSHINGOID
Buffalo hump
Amenorrhoea
Moon face
Crazed Ulcers Skin changes: ace, striae Hypertension Infection Necrosis of femoral head Glaucoma Osteoporosis Immunosuppression Diabetes
How would you investigate Cushing’s? (3)
Free cortisol in 24hr urine sample: high
Low dexamethasone suppression test: if cortisol unchanged then +ve for Cushing’s
- ACTH low = adrenal adenoma/ carcinoma, exogenous glucocorticoids
- ACTH high = Cushing disease, ectopic ACTH production
How do you differentiate between Cushing disease and ectopic ACTH production?
High dose dexamethasone test:
- no ACTH suppression = ectopic site
- ACTH suppression = Cushing disease
What test do you order if you suspect ectopic ACTH production?
CT chest, abdomen & pelvis
What test do you order if you suspect Cushing’s disease?
MRI head (pituitary)
How do you treat iatrogenic Cushing’s syndrome?
Stop steroids
How do you treat Cushing’s disease?
Transsphenoidal removal of pituitary adenoma
