Endocrinology - Adrenal insufficiency/Addison's Flashcards
What is adrenal insufficiency?
Where the adrenal glands do not produce enough steroid hormones, particularly cortisol and aldosterone
This is life-threatening
What are the three classes of adrenal insufficiency?
Primary adrenal insufficiency (Addison’s)
Secondary adrenal insufficiency
Tertiary adrenal insufficiency
What is primary adrenal insufficiency?
Adrenal glands are damaged and not producing enough cortisol and aldosterone
The most common cause is autoimmune
What is secondary adrenal insufficiency?
Result of inadequate ACTH release from the pituitary e.g. due to loss or damage of the tissue
Can occur due to surgery to remove pituitary tumour, infection, loss of blood flow or radiotherapy
What is tertiary adrenal insufficiency?
Result of inadequate CRH release by the hypothalamus
Usually because of long term steroid treatment
- Suppresses the hypothalamus
- If these steroids are stopped suddenly the hypothalamus does not “wake up” fast enough and endogenous steroids are not adequately produced
Symptoms and signs of adrenal insufficiency
Fatigue Nausea Cramps Abdominal pain Reduced libido Anorexia Weight loss
Signs:
- Bronze hyperpigmentation
- Hypotension (particularly postural hypotension)
- Hypoglycaemia
Investigations in suspected adrenal insufficiency
Bloods - U&Es:
- Hyponatraemia is a key clue, sometimes this is the only presenting feature of adrenal insufficiency
- Hyperkalaemia can occur
- 9am cortisol can be measured (but often falsely normal)
- Short synacthen test is the gold standard diagnostic test
- ACTH :
- High in primary adrenal failure (Addison’s)
- Low in secondary adrenal failure
- Adrenal auto-antibodies - adrenal cortex antibodies and 21-hydroxylase antibodies - present in 80% autoimmune adrenal insufficiency
Imaging to consider:
- CT/MRI adrenals if suspecting an adrenal tumour, haemorrhage or other structural pathology
- MRI pituitary
Short synacthen test result meaning
Ideally perform in the morning
Give synthetic ACTH and measure blood cortisol 30 and 60 minutes later
Normally the synthetic ACTH will stimulate healthy adrenal glands to produce cortisol and levels rise
Failure of cortisol to at least double indicates Addison’s disease
Treatment of adrenal insufficiency
Replacement steroids
- Hydrocortisone is a glucocorticoid hormone and is used to replace cortisol.
- Fludrocortisone is a mineralocorticoid hormone and is used to replace aldosterone if aldosterone is also insufficient.
Advice to give to patients on steroids
To carry a steroid card and emergency ID tag to inform emergency services that they are dependent on steroids for life
To double dose during acute illness until they have recovered (to match normal steroid response to illness)
What is the main important risk of Addison’s?
Addisonian crisis
What causes Addisonian crisis?
Can be the first presentation of Addison’s
Triggered by infection, trauma or other acute illness in someone with established Addison’s
Can be due to the sudden withdrawal of long term steroids
Management of Addisonian crisis
Don’t wait for investigations before treatment as this is life
- Obs monitoring
- Parental steroids e.g. IV hydrocortisone
- IV fluid resuscitation
- Correct any hypoglycaemia
- Careful monitoring of electrolytes and fluid balance (and treatment if needed)
Presentation of Addisonian crisis
- Reduced consciousness
- Hypotension
- Hypoglycaemia
- Hyponatraemia
- Hyperkalaemia
Patients often quite unwell