Adrenals Flashcards
What is cushings syndrome?
High ACTH
What is Cushing’s disease?
High ACTH because of pituitary signaling (secondary hyper cortisol)
Recall the symptoms of cushing’s syndrome
- central Weight gain
- Muscle weakness
- Moon face
- Proximal myopathy
- Think skinn
- poor would healing
- easy bruising
- hypertension
- osteoporosis
- Type 2 Diabetis
- peripheral pitting oedema
What are the causes of Cushing’s syndrome?
Most common:
- Taking too many steroids
But also:
- Pituitary dependent Cushing’s disease
- Ectopic ACTH from lung cancer
- adrenal adenoma secreting cortisol
Which investigations would you perform to determine cushing’s syndrome?
- 24 h urine collection for urinary free cortisol
- Blood diurnal cortisol levels (changes over day)
- (cortisols usually highest at 9am and lowest at midnight, if asleep)
- –> need to get a mid-night sample without people telling it to diagnose
- Basal (9am) cortisol 800 nM
But also
- Low dose dexamethasone suppression test
Explain the prosess and interpretation of a low dose dexamethasone supression test
Dexamethasone is a artificial steroid
administerd over 48 h, 0.5mg/6h
Physiologically:
- cortisol production will be supressed to 0
- In Cushing’s: production will not be supressed!(
•End of LDDST: 680 nM
How do you determine the cause of cushings?
Dexamethasone supression test
- ACTH morning (e.g. if low: not ectopic or adrenal adenoma)
- supression of cortisol due to dexamethasone –> if it does not happen + ACTH low –> cushings
24h urine free cortisole
Midnight blood cortisol levels
How can you treat cushing’s?
Remove the cause e.g. Surgery in tumor (pituitary, adrenalectomy (bilateral, unilateral)
But also Medication:
·Inhibitors of steroid biosynthesis:
- metyrapone;
- ketoconazole
Explain the Mechanism of action and use of METYRAPONE
Anti-steriod drug to treat Cushings:
- inhibits 11ß-hydroxylase
Use:
1) Prior to surgery
- adjust dose (oral) according to cortisol (aim for mean serum cortisol 150-300 nmol/L)
- –>improves patient’s symptoms and promotes better post-op recovery (better wound healing, less infection etc)
2) Control of Cushing’s symptoms after radiotherapy (which is usually slow to take effect)
What are the side effect of Metyrapone
Explain them
11ß-hydroxylase inhibitor leading to
- Accumulation of deoxycorticosterone –> has aldosterone-like effects
- hyertension due to more water and salt retention
- More accumulation of
17α-hydroxyprogesterone –> can be converted into testosterone –> higher androgen levels
* Hirsutism in women (männlicher Behaarungstyp bei Frauen)
Explain the use and mechanism of action of Ketoconazol
Side-effect
Off-label use in (14-α-sterol demethylase (a cytochrome P-450 inhibitor) inhibits synthesis of lanosterol to ergosterol
Cushing’s syndrome
- treatment and control of symptoms prior to surgery
- orally active
Side effects:
- ·Liver damage - possibly fatal - monitor liver function weekly, clinically and biochemically
What is Conn’s syndrome?
- Benign adrenal cortical tumour (zona glomerulosa)
- Aldosterone in excess
–> increased salt+ water retention
–> Hypertension and hypokalaemia
How do you diagnose Conn’s syndrome?
Measure Hormone:
- Primary hyperaldosteronism (if high)
Measure Renin:
- Renin - angiotensin system should be suppressed (to exclude secondary hyperaldosteronism) –> Renin should be low
How do you treat Conn’s syndrome?
Explain the mechanisms of action of the pharmacological treatment including side effects
- SPIRONOLACTONE
- Converted into canrenone which is a
- mineralocorticoid receptor (MR) antagonist
- –> reduced Na+ reabsorbtion and K+ excretion
- Side effects:
·Menstrual irregularities (+ progesterone receptor)
·Gynaecomastia (- androgen receptor)
- EPLERONONE
- also MR antagonist
- but more specific: (·Less binding to androgen and progesterone receptors compared to spironolactone, so better tolerated)
Also possible:
Surgery
What are Phaeochromocytomas?
The are very rare
- tumours of the adrenal MEDULLA which secrete catecholamines –> Adrenaline, Noradrenaline
*
What are the symptoms of Phaeochromocytomas?
- Hypertension in young people
- Episodic severe hypertension (after abdominal palpation)
- More common in certain inherited conditions
- Also other symptoms like increased agression, tachycardia, dilated pupils, sweating, headache etc.
One attack can lead to death!
What is so problematic about Paeochromocytomas?
- Severe hypertension can cause myocardial infarction or stroke
- High adrenaline can cause ventricular fibrillation + death
–> One attack can be deadly