The adrenal gland clinical Flashcards
Hypofunction of the adrenal gland can result in which 3 things?
Adrenal Dysgenesis
Adrenal destruction
Impaired steroidgenesis
Adrenal disorders: hyposecretion
Primary adrenal insufficiency - Addison’s disease - autoimmune destruction
Adrenal enzyme defects - congenital adrenal hyperplasia (most commonly 21-hydroxylase deficiency)
What is Autoimmune Addison’s disease?
lymphocytic infiltrate of adrenal cortex
+ve adrenal autoantibodies (to 21-OHase) in 70% cases
Associated autoimmune diseases are common thyroid disease (20%) Type 1 diabetes mellitus (15%) premature ovarian failure (15%)
Common symptoms of primary adrenal failure
Weakness, fatigue, anorexia, weight loss
Skin pigmentation or vitiligo
Hypotension
Unexplained vomiting or diarrhoea
Possible clues to the diagnosis of adrenal failure
Disproportion between severity of illness & circulatory collapse / hypotension / dehydration
Unexplained hypoglycaemia
Other endocrine features (hypothyroidism, body hair loss, amenorrhoea)
Previous depression or weight loss
How might you diagnose adrenal insufficiency
Non-specific symptoms - so must think of the diagnosis in the first place!
Routine bloods: U&E, glucose, FBC
Early morning cortisol
>450 nmol/l (not Addison’s)
<350 nmol/l (adrenal status uncertain)
Synacthen test (and basal ACTH) - If suspicion high & patient unwell, treat with steroids and do Synacthen test later
What is the Synacthen test/Rapid ACTH Stimulation test?
Test using a chemical called tetracosactrin that tests how well your adrenals are producing cortisol
Give tetracosactrin IM or IV
What is ACTH?
Adrenocorticotropic hormone (ACTH) is a hormone produced in the pituitary gland in the brain. The function of ACTH is to regulate levels of the steroid hormone cortisol
Explain the results of Synacthen test/Rapid ACTH Stimulation test: abnormal and normal
Abnormal => Adrenocortical
insufficiency => then test Plasma ACTH
Normal - Excludes primary adrenocortical insufficiency
An abnormal Synacthen test leads you to testing for plasma ACTH levels. What is the diagnosis if plasma ACTH is either suppressed or elevated?
Suppressed - secondary adrenocortical insufficiency
Elevated - Primary adrenocortical insufficiency
Glucocorticoid replacement drug names
Hydrocortisone
Prednisolone
Dexamethasone
Why are glucocorticoid replacement drugs given in divided doses?
To mimic normal diurnal variation
Name a mineralocorticoid
Aldosterone
Name a Corticocoticoids
Cortisol
Mineralocorticoid replacement: what is the drug of choice, dose etc
Synthetic steroid - Fludrocortisone (drug of choice)
Binds to mineralocorticoid (aldosterone) receptors
50-300 micrograms daily
Adjust dose according to:
clinical status (postural BP, oedema)
U&E
plasma renin level
Management of stressed patients
Minor short-lived illness or stress - double glucocorticoid dose
Major illness or operation
(especially if nil by mouth or GI upset)
100mg hydrocortisone iv stat
Who needs special care when on steroids?
Hypoadrenal patients on replacement steroids
Patients on steroids in doses sufficient to suppress the pituitary adrenal axis (>7.5mg prednisolone daily, or equivalent)
Patients who have received such treatment during the previous 18/12 (HPA axis may still be suppressed)
What should be done in short lived illness or stress for patients who need special care (they are on steroidal treatment)?
Double glucocorticoid dose
What should be done if there is major illness or surgery for patients who are on steroids?
(especially if nil by mouth or GI upset)
100mg hydrocortisone iv stat
50-100mg HC iv 8-hourly
as stress abates, reduce HC by 50% per day until back on usual replacement dose
What are the 3 important ‘self care’ rules that patients on steroids should follow
Never miss steroid doses/stop steroids
Double the hydrocortisone dose in the event of intercurrent illness (eg flu, UTI)
If severe vomiting or diarrhoea call for help without delay (likely to need IM hydrocortisone)
What are some endocrine causes of hypertension?
Primary hyperaldosteronism - unilateral adenoma
bilateral hyperplasia
Rarer causes - cushing’s syndrome, acromegaly
What are the hypersecretion disorders involving the cortex and the medulla?
Cortex - cushings (cortisol, androgens)
-Conn’s syndrome (aldosterone)
Medulla -
phaechromocytoma (catecholamines)
Side effects of glucocorticoid therapy
Muscle wastage
Loss of percutaneous fat stores gives appearance of “thinning skin” making it more fragile.
Increased severity and frequency of infection
ACTH-dependent cushing’s syndrome
75% cases - pituitary tumour (cushing’s disease)
5% - ectopic ACTH secretion - lung carcinoid
