Adrenal Insufficiency

Question 1

What is adrenal insufficiency?

Answer 1

Adrenal glands do not produce enough steroid hormones:

• cortisol
• aldosterone
• -> life threatening unless hormones replaced

Question 2

How is adrenal insufficiency classified?

Answer 2

Primary adrenal insufficiency:
- glands have been damaged
Secondary adrenal insufficiency:
- inadequate ACTH stimulating the adrenal gland (loss/damage to pituitary)
Tertiary adrenal insufficiency:
- inadequate CRH released from hypothalamus

Question 3

What causes primary adrenal insufficiency?

Answer 3

Addison’s Disease - usually autoimmune

Question 4

What causes secondary adrenal insufficiency?

Answer 4

Damage to pituitary:
- surgery
- infection
- loss of blood flow 
- radiotherapy
Sheehan's syndrome:
- massive antepartum haemorrhage --> pituitary necrosis

Question 5

What causes tertiary adrenal insufficiency?

Answer 5

Patients on long term oral steroids (> 3 weeks) –> suppression of the hypothalamus
When exogenous steroids are suddenly withdrawn, hypothalamus doesn’t wake up fast enough –> endogenous steroids not adequately produced

Question 6

What are the symptoms of adrenal insufficiency?

Answer 6

Fatigue
Nausea
Cramps
Abdominal pain
Reduced libido

Question 7

What are the signs of adrenal insufficiency?

Answer 7

Bronze hyper pigmentation to skin
–> ACTH stimulates melanocytes to produce melanin
Hypotension (particularly postural hypotension)

Question 8

Which abnormality on blood tests might suggest adrenal insufficiency?

Answer 8

HYPONATRAEMIA

May also be hyperkalaemia

Question 9

How is adrenal insufficiency diagnosed?

Answer 9

Short synacthen test (ACTH stimulation test)

Question 10

What would ACTH levels show in adrenal insufficiency?

Answer 10

Primary –> ACTH high (pituitary trying to stimulate failing gland)
Secondary/tertiary –> ACTH low (that is the reason cortisol is low)

Question 11

Which antibodies might be present in Addison’s?

Answer 11

Adrenal cortex antibodies

21-hydroxylase antibodies

Question 12

How is the short synacthen test carried out?

Answer 12

Ideally done in the morning
Patient given synacthen (synthetic ACTH)
Blood cortisol measured at baseline, 30 and 60 mins after administration

Question 13

How is the short synacthen test interpreted?

Answer 13

Synthetic ACTH will stimulate a healthy adrenal gland (secondary adrenal insufficiency) –> cortisol at least doubles
If cortisol fails to rise (less than double the baseline) –> primary insufficiency (Addison’s)

Question 14

How do you differentiate between primary and secondary adrenal insufficiency?

Answer 14

ACTH levels
(used to used long synacthen test)

Question 15

How is adrenal insufficiency treated?

Answer 15

Replacement steroids - titrated to signs, symptoms + electrolytes
- hydrocortisone (replaces cortisol)
- fludrocortisone (replaces aldosterone)
Patients given a steroid card + emergency ID tag (shows they are dependent on steroids)

Question 16

How should steroid doses be changed during an acute illness?

Answer 16

Double hydrocortisone dose in infection, trauma or surgery

Keep fludrocortisone the same

Question 17

What are the features of an Addisonian Crisis?

Answer 17

• reduced consciousness
• hypotension
• hypoglycaemia
• hyponatraemia
• hyperkalaemia
• severe abdo pain, N&V
• feeble rapid pulse
• -> very unwell, life-threatening

Question 18

What causes an Addisonian crisis?

Answer 18

May be first presentation of Addison’s disease
Or triggered by infection, trauma or other acute illness in patient with establishes Addison’s
Can be causes by withdrawal of long term steroids
Bilateral adrenal haemorrhage due to meningococcal sepsis (Waterhouse-Friderichsen’s syndrome)

Question 19

How is an addisonian crisis managed?

Answer 19

ABCDE
IV hydrocortisone 100mg STAT, then 100mg every 6 hours
IV fluids
IV glucose to correct hypoglycaemia
Identify + treat cause
Close monitoring of electrolytes + fluid balance