Cushings syndrome Flashcards
What electrolyte imbalance does cushings syndrome cause
Hypokalemic metabolic alkalosis
What is cushings syndrome caused by
Cortisol excess
Why does cushings cause hypokalemia
Cotisol -> stimulates aldosterone, increases Na+ and water retention - increases K+ excretion
Electrolyte imblanaces in cushings
High bicarb - pH alkalosis
low potassium
When do you do dynamic testing for hormones
Hormone is lacking - stimulate
Hormone being produced in excess - supress
Thyroid horomone cycle
Hypothalamus -> TRH ->pituitary -> TSH -> thyroid -> T4 +T3
Somatostatin + dopamine from hypothalamus inhibit TSH release from pituitary
How assess thyroid function
measuring TSH, free T4 and free T3
Primary hyperthyroidism on bloods
Too much free T4 - supressed TSH
Cushing syndrome vs disease
Syndrome = clinical features
Disease = features + piuitary source
Where do aldosterone vs cortisol originate
Mineralcorticoid -> aldosterone
Glucocorticoid - cortiosl
Signs of cushings
Obesity - central, nuchal or SC fat pads, thin arms and legs
Plethora - red
Moon face
Extensive striae
Decreased libido Menstrual changes
Hirsutism
HPTN
Ecchymoses - extensive skin brusining
Poor healing, skin fragility
Lethargy, depressionn
Abnormal glucose toleranec
Decreased libido
Dorsal kyphosis
Types of cushings syndrome
ACTH dependent and independent
What causes cushings disease
Pituitary tumours -> ACTH
ACTH dependent
What auses cushings syndrome
Adrenal adenoma -> cortisol
ACTH independent
Why do midnigth cortisol in cushings
Normlaly lowest at this point - in cushings loss of diurnal variation
Investigations for cushings
Elevated 24 hour urinary free cortiosl exretion
Overnight 1mg dex supression test
Plasma cortisol
What test for in 24 hour urine cortiols excretion
Cortisol:creatinine ratio
How do dex supresson test + positive results
give 1mg dex at 11pm
Test at 9am
Cushings if 9am cortisol not supressed eg >50
What investigations do if undetectable ACTH
Suggests adrenal pathology -> adrenal imaging - CT scan
What investigation do if dectabel ACTH
48 hour high dose dex supress test
How do 48 hours high dose dex supression test
2mg dex every 6 hours - 8am, 2pm, 8pm, 2am
If <50% basal value after 48 hours (50-90% accepted) means supression
What does supression on high dose 48 hr dex test but not overnigth suggest
Pituitary cushings disease -> pituiatry MRI
What does elevation in both overnigth and high dose dex supressiont ests suggest
Extopic ACTH production or adrenal tumours
Pr op management in cushings
Lower cortisol - imporve wound healing and tissue repair
Meyrape
Ketoconazole
What can ketoonazole cause
Addisons disease
What is the deficinitve treatment for cushings disease
Surgery - transsphenoidal for pituitary tumours -> radiotherapy if not cured
Adrenal tumours - laparascopic or open adrenalectomy
What can low dose overnight dex supression test tell you
if there is abnormal cortisol secretion.
What can high dose dex supression 48 hour test tell you
Excess cortiols due to adrenal glands - syndrome, not supressed
OR ACTH high levels from pituitary - disease, supressed
Electrolytes in cushings
Low potassium - gluco+mineralcorticoid excess action -> K+ loss
HYPOKALEMIC METABOLIC ALKALOSIS
Excess cortisol ->
weight gain, muscle weakness, high blood pressure, diabetes, and osteoporosis.
What is cuhsings disease
Exces cortisol BUT specifically from ACTH secreting pituitary adenoma
Musculoskeletal manifestations of cushigns disease
Prozima myopathy hip - hide rising from seat
Osteopenia +osteoporosis - increased fracture rsik esp vertebral compression
Avascular necoriss of femoral head
Derm features of cushings
Hirsutism, acne, seborrheic dermatitis, thin skin, poor wound healing
Endocrine symptoms cushings
Glucose intolerance or T2DM
Mentrual irregularities - oligo or amenorrhea, decreased libido and ED HPG acis supressed
Neuropsych in cushings
Depression, anxiety, irritability, emotional lability, and cognitive deficits such as impaired memory or concentration
Sleep disturbances including insomnia or hypersomnia
CVS complications from cushgins
HPTN - sodium retntion
Increased VTE risk - hypercoagulable
Children concerns in scushings
n children, growth retardation may occur due to cortisol-mediated suppression of growth hormone secretion
Precocious puberty may be observed in some cases
What is ectopic ACTH secretion (eg small cell lung cancer) ass with?
Very low K+ levels
Will both cortisol and ACTH be supressed in cushings disease in high dose dex supress test
Yes
Which condition is both cortisol and ACTH not supressed in high dose dex test
Ectopic ACTH
First line to third line of cushings disease
First-line = trans-sphenoidal removal of pituitary tumour (hypophysectomy)
Second-line = repeat trans-sphenoidal surgery, pituitary radiotherapy
Third-line = bilateral adrenalectomy
Complications of bilateral adrenalectomy
Hypoadrenal crisis - addisons lifelong treat
Nelsons syndrome
Nelsons syndrome
Bilateral adrenectomy -> pituitary enlargement -> mass effects nad skin hyperpigmenetation
AKAjust get cushings again
