[18] Cushing's Syndrome Flashcards
What is Cushing’s syndrome?
A clinical state produced by chronic glucocorticoid excess
What are the categories of features of Cushing’s syndrome?
Catabolic effects
Glucocorticoid effects
Mineralocorticoid effects
What are the catabolic effects of Cushing’s syndrome?
Proximal myopathy
Striae
Bruising
Osteoporosis
What are the glucocorticoid effects of Cushing’s syndrome?
DM
Obesity
What are the mineralocorticoid effects of Cushing’s syndrome?
HTN
Hypokalameia
Describe the appearance of someone with Cushing’s syndrome
Moon face Acne and hirsutism Interscapular and supraclavicular fat pads Centripetal obesity Striae Thin limbs Bruising Thin skin
What are the categories of Cushing’s syndrome?
ACTH independent
ACTH dependant
What happens to ACTH in ACTH independent Cushing’s syndrome?
It is decreased due to negative feedback
What are the causes of ACTH independent Cushing’s syndrome?
Iatrogenic steroids: Adrenal adenoma / Ca Adrenal nodular hyperplasia LAME syndrome McCune-Albright
What does a carcinoma causing ACTH independent Cushing’s syndrome often cause?
Virilisation
What happens to ACTH in ACTH dependent Cushing’s syndrome?
It is increased
What are the causes of ACTH dependent Cushing’s syndrome?
Cushing’s disease
Ectopic ACTH production
What is Cushing’s disease?
Bilateral adrenal hyperplasia from ACTH-secreting pituitary tumour
Does Cushing’s disease have cortisol suppression with high dose dex?
Yes
Does ACTH independent Cushing’s have cortisol suppression with high dose dex?
No
What can cause ectopic ACTH production?
SCLC
Carcinoid tumour
What are the features of ectopic ACTH production?
Skin pigmentation
Metabolic alkalosis
Weight loss
Hyperglycaemia
Does ectopic ACTH production have cortisol suppression with high dose dex?
No
What is the first line investigation in Cushing syndrome?
24 hour urinary free cortisol
What are the other investigations that may be done in Cushings syndrome?
Late night serum or salivary cortisol Dexamethosone suppression tests ACTH testing Localisation using CT or MRI DEXA scan
When is serum or salivary cortisol highest?
In the morning
its lowest at midnight cba to make another card
What is the problem with ACTH testing in Cushing’s syndrome?
ACTH degrades very quickly after venepuncture
How is Cushing’s syndrome managed?
Treat the underlying cause
How is Cushing’s syndrome treated?
Trans-sphenoidal excision
How is adrenal adenoma/cancer treated?
Adrenelectomy
How is ectopic ACTH production treated?
Tumour excision
Metyrapone
How does metyrapone work?
Inhibits cortisol synthesis
