Clinical Aspects of Adrenal Disorders Flashcards
What hormones do the different layers of the adrenal gland produce?
- Mineralcorticoids (aldosterone)
- Corticosteroids (cortisol)
- Sex steroid (testosterone, progesterone, estrogen)
- Medulla (norepinephrine, epinephrine)
What is the approach for investigating an adrenal disorder?
- Clinical suspicion
- Test for assessing functional status
- If tumour;
• Resection?
• +/- chemo or radiotherapy - Endocrine deficiency may need correction
- Aetiology specific treatment
Name two hyposecretion disorders
- Primary adrenal insufficiency
* Adrenal enzyme defects
What is another name for primary adrenal insufficiency
Addison’s disease
What is autoimmune Addison’s disease?
- Adrenal failure
- +ve adrenal autoantibodies
- Lymphocytic infiltrate of adrenal cortex
- Associated autoimmune disease common (thyroid disease, IDDM, premature ovarian failure)
What are the symptoms associated with Primary Adrenal Failure
- Weakness, fatigue, anorexia, weight loss
- Skin pigmentation or vitiligo or diarrhoea
- Salt craving
- Postural symptoms
Name possible clues to the diagnosis of adrenal failure
- Disproportion between severity of illness and; circulatory collapse / hypotension / dehydration
- Unexplained hypoglycaemia
- Other endocrine features (hypothyroidism, body hair loss, amenorrhoea)
- Previous depression or weight loss
What is Addison’s disease?
Damage to adrenal gland and so it does no produce enough cortisol or aldosterone.
How is Addison’s disease?
- Non-specific symptoms
- Routine bloods: U+E, glucose, FBC
Random cortisol:
• > 550 nmol/l (not Addison’s)
• < 500 nmol/l (adrenal status uncertain)
• Synacthen test (and basal acth)
What is synacthen?
Synthetic ACTH test - give synthetic ACTH and take blood to see if it stimulate cortisol production
What is the treatment for Addison’s disease?
If suspicion high and patient unwell, treat with steroids and so Synacthen test later
What is the method for the short synacthen test in Addisons disease?
9am: 7ml baseline blood test for cortisol and ACTH
Give 250mig tetracosactrin (synacthen) IM or IV
930am: 7ml blood for cortisol
10am: 7ml blood test for cortisol
What else can the short synacthen test be used to diagnose?
Congenital adrenal hyperplasia by using the blood sample to analyse for 17-OH progesterone to exclude 21-hydroylase deficiency
How do you interpret the short synacthen test?
Normal:
• Normal test at 9am
• Stimulated plasma cortisol (> 500nmol/l)
If impaired cortisol response, and ACTH is elevated then diagnosis is primary adrenal failure.
If ACTH <10ng/l –> secondary adrenal failure
What drugs are used for glucocorticoid replacement?
- Hydrocortisone
- Prednisolone
- Dexamethasone
What drug is used for mineralocorticoid replacement?
Synthetic steroid, fludrocortisone
What is the action of fludrocortisone for mineralocorticoid replacement?
- Binds to mineralocorticoid (aldosterone) receptors
- 50-300 micrograms daily
Adjust dose according to:
• Clinical status (postural BP, oedema)
• U&E
• Plasma renin level
Who needs to take special care with use of steroids?
- Hypoadrenal patients on replacement steroids
- Patients on steroids in doses sufficient to suppress the pituitary adrenal axis (>7.5mg prednisolone daily, or equivalent)
What should be given for minor shot-lived illness or stress?
Double glucocorticoid dose
What should be given for major illness or operation?
100mg hydrocortisone IV stat
• As stress abates, reduce HC by 50% per day
What are three important ‘self-care’ riles for patients on steroids?
- Never miss steroid doses
- Double the hydrocortisone dose in event of intercurrent illness
- If severe vomiting or diarrhoea, call for help without delay (likely need IM HC)
Name endocrine causes of hypertension
Primary hyperaldosteronism:
• Unilateral adenoma
• Bilateral hyperplasia
Rare: • Phaeochomcytoma • Cushing's syndrome • Acromegaly • Hyperparathyroidism • Hypothyroidism • Congenital adrenal hyperplasia
Name three adrenal disorders
Cortex:
• Cushing’s syndrome (cortisol, androgens)
• Conn’s syndrome (aldosterone)
Medulla:
• Phaeochromocytoma (catecholamines)
What does Cushing’s syndrome cause?
Excess corticosteroids
