Endocrinology - Adrenal insufficiency/Addison's

Question 1

What is adrenal insufficiency?

Answer 1

Where the adrenal glands do not produce enough steroid hormones, particularly cortisol and aldosterone

This is life-threatening

Question 2

What are the three classes of adrenal insufficiency?

Answer 2

Primary adrenal insufficiency (Addison’s)

Secondary adrenal insufficiency

Tertiary adrenal insufficiency

Question 3

What is primary adrenal insufficiency?

Answer 3

Adrenal glands are damaged and not producing enough cortisol and aldosterone

The most common cause is autoimmune

Question 4

What is secondary adrenal insufficiency?

Answer 4

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

Question 5

What is tertiary adrenal insufficiency?

Answer 5

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

Question 6

Symptoms and signs of adrenal insufficiency

Answer 6

Fatigue
Nausea
Cramps 
Abdominal pain
Reduced libido
Anorexia
Weight loss

Signs:

• Bronze hyperpigmentation
• Hypotension (particularly postural hypotension)
• Hypoglycaemia

Question 7

Investigations in suspected adrenal insufficiency

Answer 7

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

Question 8

Short synacthen test result meaning

Answer 8

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

Question 9

Treatment of adrenal insufficiency

Answer 9

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.

Question 10

Advice to give to patients on steroids

Answer 10

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)

Question 11

What is the main important risk of Addison’s?

Answer 11

Addisonian crisis

Question 12

What causes Addisonian crisis?

Answer 12

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

Question 13

Management of Addisonian crisis

Answer 13

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)

Question 14

Presentation of Addisonian crisis

Answer 14

• Reduced consciousness
• Hypotension
• Hypoglycaemia
• Hyponatraemia
• Hyperkalaemia

Patients often quite unwell