[11] Adrenal Insufficiency Flashcards
What is Addison’s disease also known as?
Primary adrenal insufficiency
What is Addison’s disease?
A rare but fatal disease whereby there is destruction of the adrenal cortex, which leads to glucocorticoid (cortisol) and mineralocorticoid (aldosterone) deficiency
What may the signs and symptoms of Addison’s disease be misdiagnosed as?
Viral infection or anorexia nervosa
How can Addison’s disease be differentiated from viral infection or anorexia nervosa?
In these conditions, potassium is decreased, but in Addison’s it is increased
What are the causes of Addison’s disease?
- Autoimmunity
- TB
- Adrenal mets
- Lymphoma
- Opportunistic infection in HIV
- Adrenal haemorrhage
- Congential
What % of cases of Addison’s disease in the UK are caused by autoimmunity?
80%
Give 3 cancers that may metastase to the adrenals
- Lung
- Breast
- Renal
Give two conditions that might cause adrenal haemorrhage
- Antiphosholipid syndrome
- SLE
What are the causes of secondary adrenal insufficiency?
- Iatrogenic
- Hypothalamic pituitary disease
How can secondary adrenal insufficiency be caused iatrogenically?
Due to long-term steroid therapy leading to suppression of the pituitary-adrenal axis
When does the suppression of the pituitary adrenal axis due to steroid therapy become apparent?
Only on the withdrawal of steroids
How does hypothalamic pituitary disease lead to secondary adrenal insufficiency?
Due to decreased ACTH production
What are the symptoms of adrenal insufficiency?
- Lean and tanned appearance
- Weakness
- Anorexia
- Dizziness and faints
- Flu-like myalgia or arthralgia
- Depression
- Psychosis
- Nausea and vomiting
- Abdominal pain
- Diarrhoea/constipation
How is adrenal insufficiency investigated?
- Blood tests
- Short ACTH stimulation test with Synacthen
- ACTH
- 21-Hydroxylase adrenal autoantibodies
- Plasma renin and aldosterone
- AXR/CXR
What is found on blood tests in adrenal insufficiency?
- Decreased sodium and glucose
- Increased potassium and calcium
- Uraemia
- Eosionphilia
- Anaemia
How is a short ACH stimulation test carried out?
You do plasma cortisol before, and half an hour after, Synacthen 250mcg IM
What does the result of a short ACTH stimulation test tell you?
Addison’s can be excluded if 30 min cortisol >550nmol/L
What may confuse the result of a short ACTH stimulation test?
- Steroid drugs
- Pregnancy
- Contraceptive pill
What effect might steroid drugs have on short ACTH stimulation test?
They might interfere with assays, so have to confirm with lab
What will be found on ACTH testing in Addison’s disease?
9am ACTH is inappropriately high, at >300ng/L
What will be found on ACTH testing in secondary adrenal insufficiency?
9am ACTH is low
How is adrenal insufficiency treated?
- Glucocorticoid replacement
- Mineralocorticoid replacement
- Androgen replacement
- Self-care advise
What is used for glucocorticoid replacemet in adrenal insufficiency?
Hydrocortisone is usually used, but long-acting glucocorticoids such as prednisolone and dexametasone are sometimes used
Why are longer acting glucocorticoids such as prednisolone and dexamethasone sometimes used in adrenal insufficiency?
To avoid the peaks and troughs which may occur with hydrocortisone
