Adrenal Disease Flashcards
Adrenal Microanatomy
- Capsule
- Glomerulosa – produces mineralocorticoids
- Fasciculata – produces glucocorticoids
- Reticularis- produces sex steroids
- Medulla
“The deeper you go, the sweeter it gets”
Adrenal anatomy
has only 1 central vein and 57 adrenal arteries
- The left adrenal drains into the left renal vein
- The right adrenal drains directly into the IVC
To measure adrenal output, a cannula is placed through the IVC and into the adrenal vein
- 31-year-old presents with profound tiredness
- Acutely unwell a few days
- Vomiting
Data
- Na: 125, K: 6.5, U: 10, Glucose: 2.9mM
- FT4 < 5nM, TSH >50mU/L
low Na, high potassium, low glucose
hyponatraemia + hyperkalaemia = deficiency of mineralocorticoid - aldosterone
hypoglycaemia: deficiency of glucocorticoid- cortisol
ADDISON’S DISEASE
define Addison’s disease
Addison’s disease = adrenal insufficiency
Deficiency of mineralocorticoid and glucocorticoid
common causes of Addison’s disease (developed and developing countries)
autoimmune disease (developed countries
Tuberculosis of adrenal glands (developing countries)
primary hypothyroidism + addison’s disease =
SHMIDT’S SYNDROME
PGAI (Polyglandular autoimmune syndrome) Type 2.
Tests for Addison’s disease
Synacthen test:
- Measure cortisol + ACTH at the start of the test
- Administer 250microgram synthetic ACTH by IM injection
- Check cortisol at 30 and 60 minutes:
*If cortisol RISES A LOT = INTACT adrenals
*If cortisol does NOT rise= do NOT have intact adrenals
NOTE: Healthy people should produce > 550 nM of cortisol within 30 minutes
- Results of short synacthen test:
o ACTH > 100ng/dl – HIGH
o Cortisol < 10nM at 30 mins – LOW
o Cortisol < 10nM at 60 mins – LOW
What urgent treatment is needed?
results indicate adrenal insufficiency
Normal 0.9% Saline infusion over 1 hour and IV hydrocortisone
- Need to rehydrate the dehydrated hypotensive patient + Give IV hydrocortisone at the same time as giving saline infusion
- Saline should go first as it will work immediately
complications of addison’s disease
People die of hyperkalaemia – can lead to arrythmias AND/ OR hypotension and shock
- 32 year old present with hypertension
- He is noted to have an adrenal mass
What are the possible adrenal masses and describe there significance
- Adrenal medullary tumour: Phaeochromocytoma: adrenaline secreting tumour = SUDDEN episodic rises in BP
- Conn’s syndrome : secretes aldosterone: retention of sodium and loss of potassium
- Cushing’s syndrome: secretes cortisol : Moon face, buffalo hump, thin shiny skin
These 3 ALL cause hypertension + hypokalaemia
(less so for phaeochromocytomas)
HIGH levels of urinary catecholamines indicates what
pheochromocytoma
management of pheochromocytoma
- Fluids first as alpha blockade can decrease BP
- Give alpha-blockade NEXT (e.g. phenoxybenzamine or doxazosin)
- then beta blockade to prevent reflex tachycardia
-then later: Cure = surgical removal of tumour
So:
FABC
complications of pheochromocytoma
secretes huge amounts of adrenaline:
sudden severe hypertension, arrhythmias (VF) and sudden cardiac death
- Genetic syndromes associated with Phaeochromocytoma
MEN 2, NF I, VHL syndrome
- Hypertensive 33-year-old
- Na: 147, K: 2.8, U: 4,0, Glucose: 4mM
- Plasma aldosterone- RAISED
- Plasma renin SUPPRESSED
what is the diagnosis:
Conn’s syndrome/ Primary hyperaldosteronism
what is Conn’s syndrome/ Primary hyperaldosteronism
adrenal gland secretes high levels of aldosterone autonomously =
hypernatraemia + hypokalaemia+ hypertension and this will in turn suppress the renin at the JGA
- 34-year-old obese woman with T2DM, presents with hypertension and bruising
- Na: 146, K: 2.9, U: 4.0, Glucose 14.0
- Aldosterone < 75 (LOW)
- Renin LOW
What is the diagnosis
- Cushing’s syndrome
causes of Cushing’s syndrome
- oral steroids (this is the most common)
- Adrenal tumour producing cortisol without ACTH
- Pituitary tumour producing ACTH: Pituitary dependent Cushing’s disease
- Ectopic tumour producing ACTH: lung cancer
Test for Cushing’s syndrome
Which dynamic test is needed to confirm Cushing’s?
- 9am cortisol- elevated normally so will not help to distinguish
- 12 midnight cortisol- suppressed normally but high in Cushing’s
definitive diagnosis = - Dexamethasone suppression test
explain Dexamethasone suppression test
Dexamethasone is a VERY potent steroid
so will switch off ACTH normally + suppress cortisol to UNDETECTABLE LEVELS
In Cushing’s, there will NOT be suppression and it will keep on making the hormone
- MOST COMMON cause for Cushing’s syndrome
Being on oral steroids: becolmethasone inhalers etc
- An obese 35-year-old patient has the following results:
- 9am cortisol (Monday): 650nM
- Given 0.5mg dexamethasone every 6 hours for 48 hours- low dose dexamethasone suppression test
- 9am cortisol (Wednesday) < 50nM
what is the diagnosis
- Normal obese person: pseudo-Cushing’s syndrome
Obesity is a growing common reason now
Tell her she does not have any serious adrenal problem; she needs help for weigh loss
- 9am cortisol (Monday): 650nM
- Given 0.5mg dexamethasone every 6 hours for 48 hours- low dose dexamethasone suppression test
- 9am cortisol (Wednesday): 500nM NOT <50nM
what is the diagnosis
- Cushing’s syndrome
What is the next step once you have found cushing’s syndrome following low dose dexamethasone suppression test?
-Sampling from the pituitary (IPSS)
inferior petrosal sinus sampling
*measures ACTH levels in the veins near pituitary and compares them with the periphery- look at the gradient*
why is high dose dexamethasone suppression test not useful
VERY INACCURATE (high false positive rate)
Inferior Petrol sinus Sampling with CRH stimulation
- Catheterise patient: needle in groin and into the cranial vessels and take blood and measure ACTH in the gland
- Take blood from the right and left pituitary as well as a peripheral vein
- Measure prolactin (to prove you are in the right place
- Inject CRH and if there is a high rise in ACTH in either pituitary vein (but NOT peripheral), this proves that there is a pituitary source of ACTH
Will need surgery
how to distinguish from pituitary dependent and ectopic causes of cushing’s
Inferior petrosal sinus sampling
a) if raised pituitary: peirpheral ACTH ratio –> PITUITARY DEPENDENT
–>ca follow up with pituitary MRI
b) if normal pituitary: peripheral ACTH ratio- EITHER i) adrenal tumour or ii) ectopic ACTH
–> adrenal CT/CT abdomen - adrenal tumour
–>CXR/CT thorax- ectopic ACTH
Why is adrenal failure worse than pituitary failure?
Because at least in pituitary failure you still have aldosterone left
How do you differentiate between primary and secondary adrenal insufficiency?
Long synacthen test
**cut off for cortisol is 900**
Diagnosis of primary hyperaldosteronism
high aldosterone: renin ratio
Diagnosis of phaeo
Plasma and 24h urinary metadrenaline measurement/ catecholamines & VMA
**raised
If you have hypertension, high sodium and low potassium with raised renin and aldosterone what is it?
secondary hyperadrenalism
i.e renal artery stenosis
Tx of cushing’s
KM -karim meeran
Ketoconazole and metyrapone
