Tutorial 4 - Adrenal Disorders Flashcards
(13 cards)
CASE 1
Man
25-year old
Presenting Complaint/History of PC/Examination
- presents following an episode of collapse
- has fainted twice on his journey to work recently
- put this down to the stress of commuting
- hypotensive on examination
- lying blood pressure = 90/60mmHg
- fell to 70/40mmHg on standing
- some increased pigmentation on his palmar creases
- patches of vitiligo on his face
What is the diagnosis?
[CASE 1]
Addison’s Disease
What investigations should be performed? How would you confirm the diagnosis?
[CASE 1]
INVESTIGATIONS
Renal Function (U&Es)
- Check K+ and Na+
- Low Na+ and High K+
- Low intravascular volume
- Therefore, low BP
Cortisol and ACTH
- Check 9am cortisol due to its diurnal release
- ACTH high
- Cortisol low
- This differentiates between primary and secondary adrenocortico failure
Synatchen Test
- Give synthetic ACTH
- If no cortisol rise, then Addison’s
- >450 = not Addison’s
- Addison’s have a flat, sub-optimal cortisol response
Antibodies
- Adrenal antibodies confirm autoimmune problem
- Check 17 and 21 hydroxylase antibodies
Why has he got increased pigmentation?
[CASE 1]
Increased ACTH due to lack of cortisol
ACTH has same precursor molecule (POMC) as MSH
Therefore, increased MSH
Stimulates melanocortin-1 receptors
Increased pigmentation in places such as:
- palmar creases
- buccal mucosa in mouth
What treatment should he receive?
[CASE 1]
ACUTE (2 days)
Hydrocortisone (paraenteral)
- 2 methods of administration
- 200mg over 24 hours continous infusion
- or 4 doses per day
- preferred to do it I.M. because of slower absorption and longer lasting actions
- High amount replaces both cortisol and aldosterone
Saline (IV)
- 0.9% normal saline
- normally 2-3L in 24 hours
- replaces water and salt
- improve blood pressure
- improve postural drop
CHRONIC
Hydrocortisone
- Tablets
- 20mg in 24 hours
- 10mg in morning (high cortisol in morning)
- 5mg at lunch
- 5mg at dinner
- 3x a day
- Mimic diurnal release of cortisol
Fludrocorisone (or other synthetic aldosterone)
- not needed acutely because high amounts of hydrocortisone can mimic aldosterone action
- this is because it can bind to MR aldosterone receptors
CASE 2
Woman
56 year old
Attends the endocrine outpatient clinic
Presenting Complaint/History of PC/Examination
- Six month history of weight gain and hirsutism.
- Reached the menopause four years previously
- Thinks her symptoms may just be due to the menopause.
- Recently diagnosed with type 2 diabetes
- Plethoric face
- Centripetal obesity
- Abdominal striae
- BMI = 32 kg/m2
- BP = 160/90mmHg
- Couldn’t rise from squatting to standing
What is a plethoric face?
[CASE 2]
Red-faced
What is the most likely diagnosis?
[CASE 2]
Cushing’s Syndrome
Can be ACTH dependent or ACTH independent
ACTH DEPENDENT
- pituitary adenoma
- Cushing’s Disease
- ectopic ACTH
- paraneoplastic syndrome (typically due to lung cancer)
ACTH INDEPENDENT
- excess cortisol
- adrenal adenoma
- adrenal carcinoma
- micro/macro hypernodular
What investigations would you do to confirm this?
[CASE 2]
Urine Collection
- 24 hours
- Measure cortisol
- In Cushing’s, there is high cortisol excretion in urine
Dynamic Dexamethasone Suppression Test
- Low dose or high dose
- In low dose, 0.5mg 4x for 2 days
- In high dose, one dose at bedtime
- See whether it endogeneously suppresses ACTH
- Would expect cortisol <50
- ACTH being undetectable means the Cushing’s is ACTH independent and is most likely an adrenal problem
CT/MRI Adrenals
- MRI favoured in young people as it is non-ionising
- CT if surgery is needed
Midnight Cortisol
A low dose dexamethasone suppression test is performed:
9AM ACTH at start of test: <5ng/L (undetectable)
Serum cortisol after 48h = 267 nmol/L
How do these results help you to make the diagnosis?
ACTH Independent
ACTH is low at the beginning, which would not be the case in ACTH dependent
Cortisol isn’t suppressed
What investigation should be performed next?
[CASE 2]
CT the adrenals
What does the CT scan of the adrenals show?
[CASE 2}
Right Adrenal Mass
Should be a symmetrical outpouching for the adrenals in a healthy patient
How should the patient be treated?
[CASE 2]
ACUTE
To lower cortisol, give cortisol lowering drugs:
- Metyrapone
- Ketoconazole
This promotes wound-healing and prevents infection risk
CHRONIC
Surgery
- Unilateral adrenalectomy because the whole adrenal gland has to be removed
