ADRENAL FAILURE 2 Flashcards
What are clinical features of Cushing’s syndrome?
Too much cortisol Centripetal obesity Moon face and buffalo hump Proximal myopathy Hypertension and hypokalaemia Red striae, thin skin and bruising Osteoporosis, diabetes
List the causes of Cushing’s syndrome
Taking too many glucosteroids
Pituitary dependent Cushing’s disease
Ectopic ACTH from lung cancer
Adrenal adenoma secreting cortisol
What investigations do you undertake to determine the cause of Cushing’s syndrome?
24hr urine collection for urinary free cortisol
Blood diurnal cortisol levels
Low dose dexamethasone suppression test
What is the low does dexamethasone suppression test?
0.5 mg 6 hourly for 48 hours
In normal individuals, cortisol should be suppressed to 0 because of the -ve feedback on the pituitary
In all patients with Cushing’s no matter the cause cortisol won’t be suppressed
What is dexamethasone?
artificial steroid which mimics cortisol
What are some drugs which are used to treat hyperadrenal disorders?
Metyrapone, ketoconazole - inhibits steroid synthesis (cushing’s syndrome)
Spironolactone, epleronone - MR antagonist (Conn’s syndrome)
What is Conn’s syndrome
Excess aldosterone due to benign adrenal cortical tumour in zona glomerulosa
How does metyrapone work?
Inhibits 11-hydroxylase preventing steroid synthesis in zona fasciculata
How and when can you use metyrapone?
Adjust dose according to serum cortisol (aim for 150-300)
Controlling Cushing’s syndrome prior to surgery
Control of symptoms after radiotherapy
- improves patient’s symptoms and promotes better post-op recovery
What are some adverse effects of metyrapone?
Hypertension on long-term administration because 11-deoxycorticosterone build up
Hirsutism in women due to increased sex steroid production
How does ketoconazole work?
At higher conc. mainly blocks 17-hydroxylase inhibiting cortisol production
Main use is anti-fungal agent, withdrawn due to risk of hepatotoxicity
What are some adverse effects of ketoconazole?
Liver damage - possibly fatal so monitor liver function weekly
What are the symptoms of Conn’s syndrome?
Hypertension and hypokalaemia
How can you tell if a patient has Conn’s syndrome?
Conn’s is primary hyperaldosteronism meaning the renin-angiotensin system should be suppressed due to -ve feedback
How does spironolactone work?
Gets converted to many active metabolites in liver including canrenone which is an antagonist of the mineralocorticoid receptor
Blocks sodium reabsorption and potassium excretion in tubules
