Adrenal Insufficiency Flashcards
Causes of Adrenal insufficiency?
Addisons disease
Secondary adrenal insufficiency
Tertiary adrenal insufficiency
Addisons disease: key points
- most common cause is autoimmune
- specific condition → adrenal glands are damaged
- reduced secretion of cortisol and aldosterone
- also called primary adrenal insufficiency
Secondary adrenal insufficiency: key points
- result of inadequate ACTH stimulating the adrenal glands, resulting in low cortisol release
- loss of damage to the pituitary gland
- can be due to surgery, tumour, infection, loss of blood flow or radiotherapy
- Sheehan’s syndrome → massive blood loss during childbrith leads to pituitary gland necrosis.
Tertiary adrenal insufficiency: key points
- inadequate CRH release by the hypothalamus
- usually → patients being on long term oral steroids (>3 weeks) causing suppression of the hypothalamus.
- when the exogenous steroids are suddenly withdrawn the hypothalamus does not “wake up” fast enough and endogenous steroids are not adequately produced
- therefore long term steroids should be tapered slowly to allow time for the adrenal axis to regain normal function.
Pathophysiology: adrenal axis
CRH released by hypothalamus
ACTH released by Anterior pituitary
Cortisol released by adrenal cortex (fasiculata)
Clinical presentation of Adrenal insufficiency
Symptoms
- fatigue
- nausea
- cramps
- abdominal pain
- reduced libido
Signs
- bronze hyperpigmentation to skin (negative feedback loop increasing ACTH levels by the pituitary gland → stimulates melanocytes to produce melanin)
- hypotension (particularly postural)
Blood investigation adrenal insufficiency?
- Hyponatraemiais a key biochemical clue. Sometimes the only presenting feature of adrenal insufficiency is hyponatraemia.
- Hyperkalaemia is also possible.
Test of choice to diagnose adrenal insufficiency?
Short synacthen test
What is the short synacthen test?
ACTH stimulation test
- It is ideally performed in the morning when the adrenal glands are most “fresh”.
- The test involves givingsynacthen, which issynthetic ACTH.
- The blood cortisol is measured at baseline, 30 and 60 minutes after administration. The synthetic ACTH will stimulate healthy adrenal glands to produce cortisol and the cortisol level should at least double.
- A failure of cortisol to rise (less than double the baseline) indicatesprimary adrenal insufficiency(Addison’s disease).
if suspecting an adrenal tumour, haemorrhage or other structural pathology?
CT/MRI adrenals
MRI pituitarygives further information about?
pituitary pathology
Treatment of adrenal insufficiency?
- Treatment of adrenal insufficiency is with replacement steroids titrated to signs, symptoms and electrolytes.Hydrocortisoneis a glucocorticoid hormone and is used to replacecortisol.
- Fludrocortisoneis a mineralocorticoid hormone and is used to replacealdosteroneif aldosterone is also insufficient.
- Patients are given asteroid cardand anemergency ID tagto alert emergency services that they are dependent on steroids for life. Doses should not be missed as they are essential to life.Doses are doubledduring an acute illness until they have recovered to match the normal steroid response to illness.
Addisonian crisis (AKA adrenal crisis) presents with?
term used to describe an acute presentation ofsevere Addisons, where the absence of steroid hormones leads to a life threatening presentation. They present with:
- Reduced consciousness
- Hypotension
- Hypoglycaemia, hyponatraemia, hyperkaemia
- Patients can be very unwell
Management of Addisonian Crisis
- Intensive monitoring if unwell
- Parenteral steroids (i.e. IV hydrocortisone 100mg stat then 100mg every 6 hours)
- IV fluid resuscitation
- Correct hypoglycaemia
- Careful monitoring of electrolytes and fluid balance
Specific sign you might see in someone with Addison’s disease
Hyperpigmentation (face, neck, palmar creases)
It is caused by the stimulant effect of excess adrenocorticotrophic hormone (ACTH) on the melanocytes to produce melanin.
