Adrenal cases Flashcards
The zona fasiculata makes cortisol
- True or false?
TRUE
Describe the adrenal microanatomy
What do the different layers of the adrenal cortex and medulla produce?
- Medulla - produces catecholamines
- Reticularis - Sex steroids
- Fasiculata - Cortisol
- Glomerulosa - Aldosterone
Case
31 year old presents with profound tiredness, been acutely unwell for a few days and been vomiting
Results:
- Na = 125
- K = 6.5
- U = 10
- Glucose = 2.9mM
- Free T4 <5nM
- TSH > 50U/l
- What does the TSH suggest?
a) A TSH producing pituitary adenoma
b) Graves disease
c) A toxic thyroid nodule
d) Primary hypothyroidism
e) De Quervains (viral) thyroiditis - Does the answer to (1) explain the other abnormal results)
- What does this person have?
- What would their short synacthen test show?
- Suggests thyroid failure, hypothyroidism can cause profound tiredness. d) primary hypothyroidism
- There is also hyponatraemia, hyperkalaemia - a deficiency of mineralcorticoid, hypoglycemia and deficiency of glucocorticoid.
Deficiencies in all areas is a sign of Addison’s disease
- They have both Addison’s disease and primary hypothyroidism so they have Schmidt’s syndrome
- High ACTH and low cortisol
Which is the most appropriate test for Addison’s disease?
- Low dose dexamethasone suppression test
- High dose dexamethasone suppression test
- Synacthen test
- Glucose tolerance test
- TRH stimulation test
- Short synacthen test
- Measure cortisol and ACTH at start of test
- Administer 250micrograms synthetic ACTH by IM injection
- Check cortisol at 30 and 60 minutes - cortisol should rise
Case
A 32 year old presents with hypertension. He is noted to have an adrenal mass.
- What are the three possible differentials?
Further investigations show high levels of urinary catecholamines
- What is the likely cause?
- Why is urgent drug treatment required?
- What is the cure?
1.
- Phaeochromocytoma - adrenal medullary tumor secreting adrenaline
- Conn’s syndrome - adrena tumor secreting aldosterone
- Cushing’s syndrome - secretes cortisol
- Phaeochromocytoma - adrenal medullary tumor that secretes adrenaline, and can cause severe hypertension, arrhythmias and death
- Immediate treatments needed are:
- Urgent alpha blockade with phenoxybenzamide
- Add beta blocker (SECOND)
- Finally arrange surgery
- Cure is to surgically remove the adrenal mass
Case
Hypertensive 33 year old
- Na = 147
- K = 2.8
- U = 4
- Glucose = 4.0mM
- Plasma aldosterone raised
- Plasma renin suppressed
- What is the diagnosis?
- Why is renin suppressed?
- Conn’s syndrome/ Primary hyperaldosteronism
- The adrenal gland secretes high levels of aldosterone autonomously. This will cause hypertension and this will in turn suppress the renin at the JGA
Case
34 year olf obese woman with type 2 diabetes, presents with hypertension and bruising
Results:
- Na = 146
- K = 2.9
- U = 4
- Glucose = 14
- Aldosterone <75 (low)
- Renin = low
- These results excludes Conn’s and suggests another hormone is causing the hypertension. True or false?
- What is the likely diagnosis?
- True
- Cushing’s
Which dynamic test is the most useful for Cushing’s?
- Insulin tolerance (stress) test
- Dexamethasone suppression test
- Synacthen test
- Glucose tolerance test
- TRH stimulation test
- Dexamethasone suppression - usually with suppress cortisol levels to undetectable levels in normal people, but it won’t be suppressed in Cushing’s
What are the causes of Cushing’s syndrome?
- Being on oral steroids for something else
- Pituitary dependent Cushing’s disease (85%)
- Ectopic ACTH (5%)
- Adrenal adenoma (10%)
Case
9am cortisol (Monday) 650nM. Given 0.5mg dexamethasone every 6 hours for 48 hours. 9am cortisol (wednesday) = 500nM.
- What is the diagnosis?
a) Pituitary dependent Cushing’s disease
b) Adrenal tumor causing Cushing’s syndrome
c) Ectopic ACTH causing Cushing’s syndrome
d) Normal obese person
e) Cushing’s syndrome of indeterminate cause
E) Cushing’s syndrome
9am cortisol (Wednesday 500nm), given high dose dex suppression. 9am cortisol (friday) 170nM What is the diagnosis?
- Pituitary dependent Cushing’s disease
- Adrenal tumor causing Cushing’s syndrome
- Ectopic ACTH causing Cushing’s syndrome
- Normal obese person
- Cushing’s syndrome of indeterminate cause
What should be done next?
- Pituitary dependent Cushing’s disease
Next to do is pituitary sampling, and this has made high dose dexamethasone suppression test redundant, and is no longer performed
