addisons disease Flashcards
what is addisons disease?
- adrenal gland fails to produce adequate cortisol
- opposite of cushings where too much cortisol is made
3 types:
primary - failure of adrenal glands to produce cortisol and aldosterone
secondary- failure of pituitary gland to produce ACTH leading to cortisol deficiency
tertiary - failure of hypothalamus to secrete CRH
primary vs secondary addisons signs
primary
- hyperpigmentation
- hypotension
- hyponatremia and hyperalkemia
secondary
- no hyperpigmentation or hyperalkaemia bc aldosterone is unaffected
addisons symptoms
generalised fatigue
weight loss and loss of apetite
hypoglycemia
salt cravings - aldosterone deficiency
addisons investigations
serum cortisol - <5 (low)
ACTH stimulation - no inc in cortisol - primary
insulin tolerance test- secondary / tertiary
what effects does low aldosterone levels have on Na + K levels
- lowers Na levels
- increases K levels
procedure on insulin tolerance test
induces hypoglycaemia which should cause the pituitary to make ACTH
this will in turn cause the adrenal glands to make more cortisol
if the pituitary isn’t functioning properly, it will not release this
gold standard for measuring adrenal insufficiency
short synacthen test
initial test for primary adrenal insufficiency - addisons
9am serum cortisol level, as cortisol levels are highest in the morning and a low value would indicate adrenal insufficiency.
What general advice should be given with regards to steroids and intercurrent illness?
double steroid dose
infectious cause of addinsons disease
TB
Aetiology of primary adrenal insufficiency (2)
- Developed world: Autoimmune adrenal destruction (21-hydroxylase present in 60-90% of people)
- Developing world: TB (+ sarcoidosis)
Complications of adrenal insufficiency (2)
- Addisonian crisis (experiences by 40% of patients)
- Cushing’s syndrome
Diagnosis of adrenal insufficiency (4)
- First line: 8-9am cortisol
- Gold standard: ACTH stimulation test (short Synacthen test)
RESULTS
- Low cortisol, high ACTH, poor response to synacthen = Primary adrenal insufficiency
- Low cortisol, low/normal ACTH, poor response to synacthen = Secondary adrenal insufficiency OR hypopituitarism
Other investigations for adrenal insufficiency (4)
- U+E to test for hyponatraemia and hyperkalaemia
- Aldosterone:renin ratio - aldosterone low renin high
- Adrenal CT or MRI
- Test bloods for 21-hydrolase adrenal antibodies
Other causes of adrenal insufficiency (2)
- Adrenal metastasis (lung, liver, breast)
- Adrenal haemorrhage (eg: meningococcal septicaemia)
Risk factors for adrenal insufficiency (3)
- Female
- Adrenocortical antibodies
- Other autoimmune disease
Signs of adrenal crisis (5)
- Hyponatraemia
- Hyperkalaemia
- Profound fatigue
- Dehydration
- Vascular collapse (low BP)
Signs of adrenal insufficiency (5)
- Bronze hyperpigmented skin, particularly in palms (only in Addison’s)
- Postural hypotension
- Hypoglycaemia
- Change in body hair distribution - Loss of pubic hair in women
- Associated autoimmune condition
Symptoms of adrenal insufficiency (4)
- Weight loss
- Nausea and vomiting
- Lethargy and generalised weakness
- Salt cravings
Tell me about Primary adrenal insufficiency/Addison’s disease (3)
- Pathology is at the adrenal glands
- Decreased production of adrenocortical hormones (cortisol and aldosterone)
- High ACTH, low adrenocortical hormones
Tell me about Secondary adrenal insufficiency (4)
- Pathology is in the pituitary
- Inadequate ACTH released from pituitary
- Leading to low release of adrenocortical hormones from the adrenal gland
- Low ACTH, low adrenocortical hormones
Treatment for Adrenal insufficiency (3)
- Hydrocortisone - glucocorticoid to replace cortisol
- Fludrocortisone - mineralocorticioid to replace aldosterone if necessary
- Double the dose of hydrocortisone in trauma/infection
Treatment of Addisonian/adrenal crisis (2)
- Immediate 100mg hydrocortisone
- IV solve + dextrose (if hypoglycaemia)
- Without cortisol, you will die from adrenal crisis if you have an infection
Why do patients with primary adrenal sufficiency present with bronzed skin?
High ACTH stimulates melanocytes, resulting in hyperpigmentation
