6. Hyperadrenal Flashcards
What is Cushing’s? Causes?
Too much cortisol caused by:
Taking too many steroids
Pituitary adenoma
Ectopic ACTH from lung cancer
Adrenal adenoma secreting cortisol
Features of cushings?
Moon face + buffalo hump Centripetal obesity Proximal myopathy Hypertension + hyperkalaemia Red striae + thin skin + bruising Diabetes, osteoporosis
Diagnosis of cushings?
24h urine collection -> check for free urine cortisol
Blood diurnal cortisol levels (highest at 9am, lowest at midnight)
Low dose dexamethasone suppression test
Cushings: cortisol will fail to be suppressed
Main treatment of cushings?
11b-hydroxylase inhibitor (Metyrapone)
Inhibits synthesis of cortisol and corticosterone
Increases ACTH secretion + plasma deoxycortisol
Also increases deoxycorticosterone which has mineralocorticoid (aldosterone) effects - increased water retention leads to HYPERTENSION
Causes HIRSUTISM in women due to increased androgen production
Other treatment for cushings?
Ketoconazole (anti-fungal)
Inhibits CYP450 -> blocks steroidogenesis (at higher conc)
Can cause LIVER DAMAGE
What is Conn’s syndrome? Symptoms?
Primary hyperaldosteronism
Benign adrenal cortical tumour in zona glomerulosa
Excess aldosterone
Hypertension + hyperkalaemia
Treatment of Conn’s?
Epleronone (MR antagonist)
Similar affinity to spironolactone, better tolerated
LESS binding to progestagen/androgen recceptors
Spironolactone (K+ sparing diuretic)
Converted into active metabolite canrenone which is a competitive MR receptor antagonist
Blocks Na reabsorption + K excretion
Side effects:
- Menstrual irregularities (+ progesterone receptor)
- Gynaecomastia (- androgen receptor)
What is phaeochromocytoma? Symptoms?
Tumour of adrenal MEDULLA (not cortex) which secretes (nor)adrenaline
Episodic severe hypertension -> MI or stroke
High adrenaline -> Ventricular fib. + DEATH
Management of phaeo?
Alpha blockade + IV fluids
Then add beta blockade (prevent tachy)
