6. Hyperadrenal disorders Flashcards
what is cushing’s a result of?
too much cortisol
what are the clinical signs of cushing’s syndrome?
- thin skin
- proximal myopathy
- centripetal obesity (lemon on sticks)
- diabetes, hypertension and osteoporosis
- immunosuppression
- moon face
- red striae and bruising
what is the difference between cushing’s syndrome and cushing’s disease?
cushing’s syndrome is a collection of symptoms which could have any cause
cushing’s disease is when the cause is known to be a pituitary adenoma
what drug’s side effects are the same as the symptoms of cushing’s disease?
steroids
what can cause cushing’s?
- too many steroids
- pituitary dependent cushing’s disease
- ectopic ACTH from lung cancer
- adrenal adenoma secreting cortisol
why is measuring blood cortisol not very reliable?
the amount of blood cortisol in a patient changes with time of day - cortisol is usually highest at 9am and lowest at midnight if asleep
how can you determine the cause of cushing’s syndrome?
24h urine collection for urinary free cortisol - high level suggests cushing’s
what happens to the diurnal rhythm of cortisol if you have cushing’s?
the diurnal rhythm is lost because you have a tumour in the pituitary or adrenal gland that is pushing out cortisol all the time at a fixed rate
what does a midnight sleeping cortisol test show?
if midnight cortisol is low, cushing’s isn’t present
how is cushing’s diagnosed?
- basal cortisol of 800nM at 9am
- cortisol level of 680nM at the end of Low Dose Dexamethasone Suppression Test
what is a Low Dose Dexamethasone Suppression Test (LDDST)?
dexamethasone is a potent artificial analogue of cortisol (artificial steroid). the pituitary detects the drug and stops making ACTH (and so cortisol). normal patients will suppress their cortisol levels to 0, any cause of cushing’s will fail to suppress with low dose dexamethsone
what is the dosage given in an LDDST?
0.5mg every 6hrs for 48hrs
what are the treatment options for cushing’s?
- enzyme inhibitors of enzymes involved in cortisol production
- receptor blocking drugs
- surgery
how may a pituitary adenoma and adrenal tumour be treated?
pituitary adenoma - pituitary surgery (transsphenoidal hypophysectomy)
adrenal tumour - bilateral adrenalectomy
what drugs are used to treat cushing’s?
- metyrapone
- ketoconazole