Management of Adrenal Failure Flashcards
Clinical features of Cushing’s syndrome
high cortisol centripetal obesity moon face buffalo hump proximal myopathy hypertension hypokalaemia red striae thin skin bruising osteoporosis diabetes
list causes of Cushing’s
taking too much steroids
pituitary dependent Cushing’s disease
ectopic ACTH from lung cancer
adrenal adenoma secreting cortisol
Investigations to determine cause of Cushing’s syndrome
24h urine collection (measure free cortisol)
blood diurnal cortisol levels
low dose dexamethasone suppression test
+ve result (any cause of Cushing’s will fail to suppress cortisol)
Cut off for Cushing’s diagnosis for cortisol and LDDST tests
basal cortisol 800nM
end of LDDST 680nM
pharmacological manipulation of steroids via
enzyme inhibitors
receptor blocking drugs
Conn’s syndrome
excess aldosterone
List examples of inhibitors of steroid biosynthesis
metyrapone
ketoconazole
List examples of mineralocorticoid receptor antagonists.
spironolactone
epleronone
Metyrapone inhibits what enzyme?
11b hydroxylase
in metyrapone use steroid synthesis is arrested at what stage?
11deoxycortisol stage
Uses of metyrapone
control of Cushing’s prior to surgery
(better post op recovery)
control of Cushing’s after radiotherapy
side effects of metyrapone
hypertension in long-term
hirsutism
why was ketoconazole withdrawn as an anti fungal agent?
risk of hepatotoxicity
Surgical treatment of Cushing’s
depends on cause
pituitary surgery
bilateral adrenalectomy
unilateral adrenalectomy
cause of Conn’s syndrome
benign adrenal cortical tumour
zona glomerulosa
pharmacokinetics of spironolactone
orally active
highly protein bound and metabolised in the liver
mechanism of action of spironolactone
converted to several active metabolites e.g. canrenone (competitive antagonist of MR)
blocks Na+ resorption/K+ excretion
side effects of spironolactone
menstrual irregularities
gynecomastia
what is epleronone?
mineralocorticoid receptor antagonist
epleronone vs spironolactone
epleronone less binding to androgen and progesterone receptors so it’s better tolerated
What are phaemochromocytomas?
tumours of adrenal medulla secretes catecholamines
Clinical features of phaemochromocytomas
hypertension in young people
episodic severe hypertension (on abdo palpation)
Why are phaemochromocytomas medical emergencies?
severe hypertension > MI/stroke
high adrenaline > ventricular fibrillation +death
Management of phaemochromocytomas
eventually surgery by careful prep required as anaesthetic can > hypertensive crisis
Pharmacological treatment of phaemochromocytomas
alpha blockade (may need IV) beta blockade to prevent tachycardia
