Adrenal disease Flashcards
What are the three zones in the adrenal gland? and what hormones does each produce
GFR
Glomerulosa - produces aldosterone
Fasciculata - produces cortisol
Reticularis - produces androgens
What kind of hormone is aldosterone?
mineralocorticoid
What kind of hormone is cortisol?
glucocorticoid
What does the medulla produce in the adrenal gland?
adrenalline
What is the blood supply to the adrenal gland like?
Extensive arterial supply
only 1 vein
What is the main cause of low aldosterone, low cortisol?
ADDISON’s DISEASE
What are causes of Addison’s disease?
- TB: worldwide
- AI: UK
What is Schmitt disease?
Addison’s + hypothyroidism
What pituitary hormone triggers cortisol synthesis?
ACTH
What are functions of cortisol?
Ubiquitous - as GC receptors are found almost everywhere in the body.
- Suppress IMMUNE RESPONSE
- STRESS RESPONSE
- CATABOLISM (gluconeogenesis, glycogenolysis, lipolysis, decreases insulin, increases glucagon)
What are symptoms of Addisons?
Hypoglycaemia (cortisol deficiency) Postural hypotension (aldosterone def) Weakness, weight loss, fatigue Bronzed skin (due to excess compensatory ACTH, which activates melanocytes) GI disturbance
How do you investigate Addison’s?
Short SYNACTHEN test - measure cortisol and ACTH at start - then give synacthen - should stimulate cortisol production If it doesn't > ADDISON's
What conditions does excess function of different areas of the adrenal gland also cause?
- Conn’s (aldosterone)
- Cushing’s (cortisol)
- pheochromocytoma (adrenaline)
What are symptoms of phaeo?
hypertension
arrhythmia
death
How do you treat phaeo?
alpha blocker
THEN beta blocker
THEN surgery
What genetic conditions are linked to phaeo?
MEN2
Von Hippel Lindau
Neurofibromatosis Type 1
What occurs in Conn’s syndrome?
High levels of aldosterone
Causes hypertension, suppresses renin at JGA
How do you investigate COnn’s
Measure blood aldosterone (HIGH) and renin (LOW)
What occurs in Cushing’s?
Excess cortisol production
What are causes of Cushing’s syndrome?
- Oral steroids
- Cushing’s disease (pituitary tumour)
- Adrenal adenoma
- Ectopic ACTH
What are investigations for Cushing’s?
9am cortisol, midnight cortisol (should be high in morning, low at night)
» but in Cushing’s both will be elevated
LOW DOSE DEXAMETHASONE SUPPRESSION TEST (give dex to suppress ACTH > should suppress cortisol production)
0.5mg dexamethasone every 6 h over 48h > measure cortisol
INFERIOR PETROSAL BLOOD SAMPLING
What is the gold standard ix for Cushing’s disease
INFERIOR PETROSAL BLOOD SAMPLING
what is an alpha blocker you can use to treat phaeo
phenoxybenzamine
OR
phentolamine
Doxazocin
what is a low dose dexamethasone suppression test for
find out if the patient has Cushing’s syndorme
what do you routinely do after a + LDDST
inferior petrosal blood sampling
what will an inferior petrosal sinus sampling tell yo
if it is cushings DISEASE (aka pituitary adenoma, which is responsible for 85% of all cushings)
what can you do instead of inferior petrosal sinus sampling
you can do a high dose dexamethasone suppression test
what does a high dose dex suppression test involve
2mg dex everty 6 h
what will a high dose dex suppression test tell you
if positive: that a pituitary tumour is the cause
