Cushing's Syndrome Flashcards
what is cushings syndrome
Inappropriately elevated cortisol levels FROM ANY CAUSE
what is cushings disease
excess cortisol due to overproduction of ACTH from a pituitary adenoma. this stimulates the adrenal glands to secrete more cortisol
aetiology
ACTH dependent (80%) and ACTH independent (20%)
ACTH dependent causes of cushings
excess ACTH from a pituitary adenoma (Cushings disease)
ectopic ACTH from lung metastases
ACTH independent
exogenous cortisol intake, benign adrenal adenoma and adrenal carcinoma
epidemiology
females are more affected
presenting symptoms of cushings (history and exam)
moon face, purple striae, supraclavicular fat, increased weight, fatigue, hypertension, hyperglycaemia, muscle weakness, thin skin, easy bruising and fractures, hirsutism, acne, oligo/amennhorea, central obesity (lemon on a stick), infertility and decreased libido
when will you see pigmentation in a cushings patient
if it is ACTH dependent. increased ACTH means increased MSH
investigations (1st)
urine pregnancy test to rule out pregnancy
investigations for cushings
serum glucose,
Urinary free cortisol (24 hour)
Late-night salivary cortisol
Overnight dexamethasone suppression test
Low dose dexamethasone suppression test (LDDST)
what is the Low dose dexamethasone suppression test
Patients should be given 0.5 mg of dexamethasone at 9 a.m. and at 6-hour intervals for 48 hours, with a plasma cortisol obtained at 9 a.m., 6 hours after the last dose.
results of LDDST in cushings
In Cushing’s syndrome, serum cortisol measured 48 hrs after the first dose of dexamethasone fails to suppress below 50 nmol/L
treatment
treat underlying cause and symptoms
treatment of cushings disease
treat the pituitary adenoma with a transsphenoidal pituitary adenectomy
treatment of ectopic ACTH due to lung cancer
surgical resection of metastases
