Cortisol

Question 1

What is Cushing’s syndrome

Answer 1

Prolonged abnormal elevation of cortisol

Question 2

What is Cushing’s disease

Answer 2

Pituitary adenoma secretes ACTH, leading to abnormal elevation of cortisol.

Question 3

Describe the features of Cushing’s syndrome

Answer 3

Round in the middle with thin limbs (way to remember):
Moon face
Central obesity
Abdominal striae 
Buffalo hump
Proximal limb wasting
High levels of stress hormone:
Hypertension
Cardiac hypertrophy 
Hyperglycaemia (T2DM)
Depression
Insomnia
Other:
Osteoporosis
Easy bruising and poor skin healing

Question 4

Describe some causes of Cushing’s syndrome

Answer 4

Steroids
Cushing’s disease (pituitary adenoma)
Adrenal adenoma
Paraneoplastic Cushing’s (small cell lung cancer most common, releases ACTH)

Question 5

Describe how to diagnose Cushing’s syndrome

Answer 5

Dexamethasone suppression test

Low dose at night- high or normal cortisol levels in the morning

Question 6

Describe how to diagnose the cause of Cushing’s syndrome

Answer 6

Dexamethasone suppression test
HIgh dose at night, morning cortisol: 
Low-> Cushing’s disease
HIgh and low ACTH-> adrenal Cushing’s 
High and high ACTH->  ectopic ACTH

Question 7

Describe investigations that can be done in Cushing’s syndrome

Answer 7

24 hour urinary free cortisol as an alt to dexamethasone suppression- does not indicate underlying cause
FBC- raised WCC
U&E- K may be low due to aldosterone from an adrenal adenoma
MRI brain- pituitary adenoma
Chest CT- small cell lung cancer
Abdo CT- adrenal tumour

Question 8

Describe how to treat Cushing’s syndrome

Answer 8

Treat underlying cause

If not possible, remove both adrenal glands and give replacement hormones for life.

Question 9

Describe Addison’s disease

Answer 9

Primary adrenal insufficiency:

Adrenal glands have been damaged, resulting in a reduction in the secretion of cortisol and aldosterone

Question 10

What is the most common cause of primary adrenal insufficiency?

Answer 10

Autoimmune

Question 11

Describe secondary adrenal insufficiency

Answer 11

Inadequate ACTH stimulating the adrenal glands, resulting in low cortisol release.
This is the result of loss or damage to the pituitary gland.

Question 12

Describe the causes of secondary adrenal insufficiency

Answer 12

Surgery to remove a pituitary tumour, infection, loss of blood flow or radiotherapy.
Sheehan’s syndrome- massive blood loss during childbirth leads to pituitary gland necrosis.

Question 13

Describe tertiary adrenal insufficiency

Answer 13

Inadequate CRH release by the hypothalamus

Question 14

Describe the most common cause of tertiary adrenal insufficiency

Answer 14

Sudden steroid withdrawal:
Long term oral steroids (for more than 3 weeks) causing suppression of the hypothalamus. When the exogenous steroids are suddenly withdrawn the hypothalamus does not “wake up” fast enough and endogenous steroids are not adequately produced.

Question 15

What are the symptoms of adrenal insufficiency?

Answer 15

Fatigue
Nausea
Cramps
Abdominal pain
Reduced libido

Question 16

What are the signs of adrenal insufficiency?

Answer 16

Hyperpigmentation (ACTH stimulates melanocytes)- esp in skin creases
Hypotension- esp postural

Question 17

What investigations can be done in suspected adrenal insufficiency?

Answer 17

U&E- low Na, high K
Early morning cortisol (often falsely normal)
Short Synacthen test
ACTH- high in primary, low in secondary
Adrenal cortex antibodies
CT/MRI adrenals- tumour, haemorrhage 
MRI pituitary

Question 18

Describe how primary adrenal insufficiency is diagnosed

Answer 18

Short synacthen test:
Synthetic ACTH (synacthen) is given first thing in the morning.
Cortisol measured at baseline, 30 and 60 mins after administration.
Failure of cortisol levels to rise to at least double the baseline, indicates that the adrenal glands are not healthy.

Question 19

Describe how adrenal insufficiency is treated

Answer 19

Replacement steroids titrated to signs, symptoms and electrolytes.
Hydrocortisone.
Fludrocortisone can also be used to replace aldosterone.

Question 20

Describe some causes of Addisonian crisis

Answer 20

Sudden steroid withdrawal
First presentation of Addison’s disease
Addison’s triggered by infection, trauma or other acute illnesses.

Question 21

Describe the presentation of Addisonian crisis

Answer 21

Reduced consciousness.
Hypotension.
Hypoglycaemia, hyponatraemia, hyperkalaemia.
Patients can be very unwell.

Question 22

Describe the treatment of Addisonian crisis

Answer 22

Intensive monitoring if unwell.
Parenteral steroids (i.e. IV hydrocortisone 100mg stat then 100mg every 6 hours).
IV fluid resuscitation.
Correct hypoglycaemia.
Careful monitoring of electrolytes and fluid balance.