Endocrinology - Adrenal insufficiency/Addison's Flashcards

1
Q

What is adrenal insufficiency?

A

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

This is life-threatening

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2
Q

What are the three classes of adrenal insufficiency?

A

Primary adrenal insufficiency (Addison’s)

Secondary adrenal insufficiency

Tertiary adrenal insufficiency

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3
Q

What is primary adrenal insufficiency?

A

Adrenal glands are damaged and not producing enough cortisol and aldosterone

The most common cause is autoimmune

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4
Q

What is secondary adrenal insufficiency?

A

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

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5
Q

What is tertiary adrenal insufficiency?

A

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
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6
Q

Symptoms and signs of adrenal insufficiency

A
Fatigue
Nausea
Cramps 
Abdominal pain
Reduced libido
Anorexia
Weight loss

Signs:

  • Bronze hyperpigmentation
  • Hypotension (particularly postural hypotension)
  • Hypoglycaemia
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7
Q

Investigations in suspected adrenal insufficiency

A

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
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8
Q

Short synacthen test result meaning

A

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

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9
Q

Treatment of adrenal insufficiency

A

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.
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10
Q

Advice to give to patients on steroids

A

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)

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11
Q

What is the main important risk of Addison’s?

A

Addisonian crisis

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12
Q

What causes Addisonian crisis?

A

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

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13
Q

Management of Addisonian crisis

A

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)
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14
Q

Presentation of Addisonian crisis

A
  • Reduced consciousness
  • Hypotension
  • Hypoglycaemia
  • Hyponatraemia
  • Hyperkalaemia

Patients often quite unwell

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