Endocrine: Addison's disease (brief)

Question 1

what is Addison’s disease?

Answer 1

Addison’s disease refers a the specific condition where the adrenal glands have been damaged, resulting in reduced secretion of cortisol and aldosterone.

This is also called primary adrenal insufficiency.

The most common cause is autoimmune.

Question 2

how much of the adrenal context needs to be destroyed to produce an adrenal insufficiency?

Answer 2

90%

Question 3

what is primary adrenal insufficiency?

Answer 3

the adrenal glands have been damaged, resulting in reduced secretion of cortisol and aldosterone

Question 4

what is secondary adrenal insufficiency?

Answer 4

Secondary adrenal insufficiency is a caused by inadequate ACTH stimulating the adrenal glands, resulting in low levels of cortisol being released

Question 5

what is tertiary adrenal insufficiency?

Answer 5

inadequate corticotropin hormone (CRH) release from hypothalamus and subsequent decreased ACTH release.

nb: happens when people have been on long term oral steroids (most likely prednisolone)
nb: hydrocortisone is IV

Question 6

what are some risk factors for Addison’s disease?

Answer 6

Female sex. 
Presence of adrenocortical autoantibodies. 
Adrenal haemorrhage. 
Use of anticoagulants. 
Tuberculosis. 
Non-TB bacterial infection.
Fungal infection.
HIV.
Drugs that inhibit cortisol production.
Metastatic malignancy.
Coeliac disease.
Sarcoidosis.

Question 7

what are some clinical features of Addison’s disease?

Answer 7

Anorexia/Weight loss. 
Hyperpigmentation. 
Nausea, vomiting. 
Hypotension.
Fatigue
Nausea
Cramps/Abdominal pain
Reduced libido

Question 8

which conditions present in a similar way to Addison’s disease?

Answer 8

• Adrenal suppression due to corticosteroid therapy.
• Secondary or tertiary adrenal insufficiency (pituitary or hypothalamic lesions).
• Haemochromatosis.
• Hyperthyroidism.
• Occult malignancy.
• Anorexia nervosa.

Question 9

What investigations would you conduct to confirm a diagnosis of Addison’s disease?

Answer 9

Cortisol:
- Early morning cortisol (8-9am) has a role but is often falsely normal.

ACTH:

• A short synacthen test is the test of choice to diagnose adrenal insufficiency.
• Blood ACTH. In primary adrenal failure the ACTH level is high as the pituitary is trying very hard to stimulate the adrenal glands. In secondary adrenal failure the ACTH level is low as the reason the adrenal glands are not producing cortisol is that they are not being stimulated by ACTH.

Imaging:

• CT / MRI adrenals if suspecting an adrenal tumour, haemorrhage or other structural pathology
• MRI pituitary gives further information about pituitary pathology.

Question 10

what is the treatment for Addison’s disease?

Answer 10

glucocorticoid and supportive symptom therapy

e.g. hydrocortisone sodium succinate

1. Hydrocortisone is a glucocorticoid hormone and is used to replace cortisol.
2. Fludrocortisone is a mineralocorticoid hormone and is used to replace aldosterone.

Question 11

what are some complications of Addison’s disease?

Answer 11

• secondary Cushing’s syndrome
• osteopenia/osteoporosis
• treatment related hypertension

Question 12

what signs on examination may you find for a patient with addisons disease?

Answer 12

Bronze hyperpigmentation to skin (ACTH stimulates melanocytes to produce melanin)

Hypotension (particularly postural hypotension)

Question 13

what is Short Synacthen Test (ACTH stimulation test) and when is it used?

Answer 13

• test of choice for adrenal insufficiency
• giving synacthen, which is synthetic ACTH, in the morning
• The blood cortisol is measured at baseline, 30 and 60 minutes after administration

NB: The synthetic ACTH will stimulate healthy adrenal glands to produce cortisol and the cortisol level should at least double. A failure of cortisol to rise (less than double the baseline) indicates primary adrenal insufficiency (Addison’s disease).

Question 14

what is an Addisonian crisis?

Answer 14

the term used to describe an acute presentation of severe Addisons, where the absence of steroid hormones leads to a life threatening presentation.

 They present with:
Reduced consciousness 
Hypotension
Hypoglycaemia, hyponatraemia, hyperkaemia
Patients can be very unwell

Question 15

what is the management of an addisonian crisis?

Answer 15

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

Question 16

what hormones are secreted by the adrenal glands?

Answer 16

cortisol and aldosterone

Question 17

what does cortisol do and what is it secreted by?

Answer 17

adrenal gland

Cortisol, the primary stress hormone, increases sugars (glucose) in the bloodstream, enhances your brain’s use of glucose and increases the availability of substances that repair tissues. (think adrenaline, fight/flight response)

Question 18

what does aldosterone do and what is it secreted by?

Answer 18

• regulation of blood pressure
• increase the amount of salt (sodium) reabsorbed into the bloodstream and to increase the amount of potassium excreted in the urine