hypofunction of adrenal gland Flashcards
What is the most common cause of adrenal deficiency
Immune destruction of the adrenal gland
What is another name for primary adrenal insufficiency
Addison’s disease
What does a positive adrenal autoantibodies test (21-OHase) suggest diagnosis of
Autoimmune Addison’s in 70% of cases
What happens in addison’s disease
Lymphocytic infiltration of the adrenal cortex
What increases the chances of having Addison’s disease
Having another auto-immune condition - they tend to cluster
e.g
Thyroid disease
Type 1 diabetes mellitus
premature ovarian failure
What are the common symptoms in Addison’s disease
Weakness
fatigue
anorexia
weight loss
Skin pigmentation
Hypotension
Unexplained diarrhoea or vomiting
Salt craving
Postural symptoms
What are postural symptoms
Light headedness when standing up after lying down - due to hypotension
What causes the hypotension in Addison’s disease
The zona glomerulosa produces mineralocorticoids - aldosterone - this controls reabsorption of salt and water and in Addison’s this regulation is not present and therefore water and salt in the plasma decreases which drops the blood pressure as hypovolaemia occurs
Why is there fatigue in Addison’s disease
The zona fasciculata produces glucocorticoids - cortisol which regulates metabolism so if it is not working, less energy is being produced from glucose
What signs point towards the diagnosis of adrenal failure
Disporportion between ilness severity and hypotension and dehydration
Unexplained Hypoglycaemia
Other endocrine features such as hypothyroidism
Previous depression or weight loss
How is addison’s diagnosed
Synacthen test - assess how well adrenal gland is working by using synacthen chemical to see how well cortisol is being produced§
What does a random cortisol of over 450 nanomol/litre show
Not addison’s disease
What does a random cortisol of less than 450 nanomol/litre show
adrenal status is uncertain
What is a normal plasma cortisol in the synacthen test
more than 500 nanomol/litre
What is the difference between primary and secondary adrenal failure in the synacthen test
Primary has an ACTH over 200 nanogram/litre
Secondary has an ACTH less than 10 nanogram/litre
