Cushing's syndrome ↑cortisol Flashcards
Cushing’s syndrome basically just means what?
too much cortisol
Aetiology of ↑Cortisol can be split into what two causes?
ACTH dependent and ACTH independent
ACTH independent causes of ↑cortisol?
-3
Iatrogenic
Tumour in adrenal gland itself
Carney complex
↑cortisol in blood is called what?
hypercortisolism
ACTH independent cause of ↑cortisol is primary or secondary?
1°
ACTH independent causes of ↑cortisol:
ACTH levels?
why?
↓ACTH
lots of -ve feedback
ACTH dependent causes of ↑cortisol?
-2
Cushing’s disease
ectopic ACTH production
ACTH dependent causes of ↑cortisol:
ACTH levels?
↑ACTH
common cause of ectopic ACTH production?
small cell lung cancer
define cushing’s disease?
tumour in pituitary gland, makes ACTH
Risk Factors for hypercortisolism?
steroid use
Tumour in pituitary (cushing’s)
small cell lung cancer
adrenal gland
hypercortisolism:
how is sex effected?
low libido
hypercortisolism:
how will the pt look?
-5
Big round face – moon Lemon on a stick Stretch marks Buffalo hump Bruised skin
hypercortisolism:
MSK symptom?
Muscles feel weak
hypercortisolism:
psych symptom?
Psychotic
hypercortisolism
immune symptom?
more infections
hypercortisolism:
main NEWS chart change?
HTN
hypercortisolism:
how do U+Es change?
-1 main change
Hypokalaemia
hypercortisolism:
how does ABG change?
-1
Metabolic alkalosis
2 Main Tests to check hypercortisolism?
Overnight Dexamethasone suppression test
24hr urinary free cortisol
suspected hypercortisolism.
1st line Ix?
positive result?
Overnight Dexamethasone suppression test
morning cortisol spike still there
outline overnight dexamethasone suppression test?
step by step
- Measure ACTH levels
- Give dexamethasone at bedtime
- Measure cortisol in morning
- Compare to ACTH levels, ↓↑ACTH directs you to cause
Normal and abnormal result for overnight dexamethasone suppression test?
Normal = dexamethasone does -ve feedback so no cortisol spike in the morning Abnormal = cortisol levels stay high/ spike present
pt has abnormal dexamethasone suppression test.
when measured, ACTH low.
what are the two main causes for these results?
how could you Ix these causes further?
Cause is problem at adrenal glands - CT adrenal glands
or iatrogenic drugs - Review meds
pt has abnormal dexamethasone suppression test.
when measured, ACTH high.
what Ix do you do next?
high dose dexamethasone test
pt has abnormal ON dexamethasone suppression test.
ACTH high.
high dose dexamethasone test = cortisol suppressed
what is likely cause?
how do you Ix this cause further?
Cushing’s (pituitary adenoma)
MRI brain
with Cushing’s, why on high dose dexamethasone test is cortisol suppressed?
Cushing’s has some -ve feedback left,
thus lots of dexamethasone will cause -ve feedback and cortisol goes down.
pt has abnormal ON dexamethasone suppression test.
ACTH high.
high dose dexamethasone test = cortisol not suppressed, still very high
what is likely cause?
how do you Ix this cause further?
SC Lung Cancer
CT chest
with SCLC, why on high dose dexamethasone test is cortisol not suppressed?
because SC Lung Cancer has no negative feedback at all,
so High dose dexamethasone does nothing (cortisol stays high)
in normal person, cortisol levels in the morning?
high
in normal person, cortisol levels at night?
low
in hypercortisolism why does fat deposit in abdomen and upper back?
-4
o changes how you metabolise fat
o increases cholesterol levels
o Impaired glucose tolerance +↑BG levels – glucose stored as fat
o Cortisol is stress hormone, when body stressed it thinks it needs to stock up on food because it’s unsure when next food source will come, so ↑energy storage
in hypercortisolism,
why do you get stretch marks?
Fat deposits around abdomen
in hypercortisolism,
person has big belly with stick legs,
what do you call this feature?
lemon on a stick
in hypercortisolism,
person has fat pad on back of neck,
what do you call this feature?
buffalo hump
in hypercortisolism,
why are there bruises?
Skin very fragile
in hypercortisolism,
why is there metabolic alkalosis?
K+ excreted (Hypokalaemia) > metabolic alkalosis
What is Cushing’s disease?
cause of high cortisol is adenoma in pituitary gland
in Cushing’s disease is there -ve feedback?
some negative feedback, but little.
in Cushing’s disease how can you trigger negative feedback?
give high dose of dexamethasone
Complications of ↑cortisol on MSK esp in females?
-1
↑cortisol > bone resorption > osteoporosis
Complications of ↑cortisol on electrolytes?
what can this lead to?
↑Na+ resorbed > HTN
Complications of ↑cortisol on glucose?
what can this lead to?
↑BG
T2DM
what can trigger Pseudo-Cushing’s?
alcohol excess or severe depression
1st line treatment for Cushing’s disease?
what method is used to do this, basically how do you get to the pituitary?
resect pituitary
transsphenoidal - through nose
2nd line treatment for Cushing’s disease?
radiotherapy
hypercortisolism due to SCLC?
1st line treatment for most people?
chemoradiotherapy
hypercortisolism due to iatrogenic steroid overuse.
1st line treatment?
review need for meds
hypercortisolism due to adrenal tumour.
mainstay Mx?
-2
resect tumour or adrenalectomy
define adrenalectomy?
remove whole adrenal gland
difference between hypercortisolism generally and Cushing’s disease?
Cushing’s disease is hypercortisolism due to pituitary adenoma.
hypercortisolism generally can have multiple causes.
