Cushing's syndrome Flashcards
Define Cushing’s syndrome
A clinical state produced by excess glucocorticoids
Define Cushing’s disease
Cushing’s syndrome due to a cause originating in the pituitary gland
What are some of the features of Cushing’s syndrome?
Catabolic effects - Striae, Bruising, Osteoporosis, Proxial myopathy
Glucocorticoid effects - Obesity, DM
Mineralocorticoid effects - HTN, Hypokalaemia
What is the classical appearance of a patient with Cushing’s syndrome?
Moon shaped face Acne Hirsutism Central obesity Thin limbs Striae Bruising Thin skin Buffalo hump - interscapular fat pads
What are some of the causes of ACTH independent Cushing’s?
Iatrogenic steroids
Adrenal adenoma
Adrenal carcinoma
Adrenal hyperplasia
Will the level of ACTH be high, low, or the same in ACTH independent Cushing’s?
Low due to negative feedback
There won’t be any suppression of ACTH or cortisol with dexamethasone
Will the level of ACTH be high, low or the same in ACTH dependent Cushing’s?
High
What are some of the causes of ACTH dependent Cushing’s?
Pituitary - Cushing’s disease - ACTH secreting pituitary tumour, causes adrenal hyperplasia. Will get ACTH/cortisol suppression with dexamethasone
Ectopic ACTH secretion - Small cell lung Ca, Carcinoid tumour. No suppression with dexamethasone
What other signs would you get with ectopic ACTH secretion causing Cushing’s?
Skin pigmentation
Wt loss
Metabolic alkalosis
Hyperglycaemia
What investigations can be done in a patient with suspected Cushing’s?
24hr urinary free cortisol
Late night serum/salivary cortisol - highest in the morning, lowest at midnight
Dexamethasone suppression test - do bloods, give dexamethasone, recheck bloods within 30 minutes
CT/MRI to localise pathology
DEXA scan
What is the management of Cushing’s?
Cushing’s disease - trans-sphenoidal excision of pituitary tumour
Adrenal adenoma/carcinoma - Adrenelectomy
Ectopic ACTH secretion - tumour excision, if not possible give metyrapone (inhibits cortisol synthesis)
