Addison's Disease Flashcards
What is another term for Addison’s disease?
Autoimmune adrenalitis
What is Addison’s disease?
It is defined as a condition in which there is autoimmune destruction of the adrenal glands, resulting in reduced cortisol and aldosterone secretion
What antibodies are produced in Addison’s disease?
Anti-21 hydroxylase autoantibodies
What is the most common cause of adrenal insufficiency?
Addison’s disease
What are the nine clincial features of Addison’s disease?
Fatigue
Nausea & Vomiting
Muscle Weakness
Hyperpigmentation
Vitiligo
Salt Craving
Weight Loss
Hypotension
Syncope
In most cases where does hyperpigmentation present in Addison’s disease?
Palmar Creases
What is vitiligo?
It is characterised by pale white patches appearing on the skin
In exams, how does Addison’s disease tend to present?
The clinical features can be non-specific, it is important to look at the blood for hyponatraemia and hyperkalaemia
What are the four investigations used to diagnsoe Addison’s disease?
Blood Tests
Arterial Blood Gas (ABG)
ACTH Stimulation Test
MRI Scan
What are the seven blood test results indicative of Addison’s disease?
Decreased Sodium Levels
Increased Potassium Levels
Increased Calcium Levels
Decreased Glucose Levels
Decreased Cortisol Levels
Increased ACTH Levels
21-Hydroxylase Antibodies
When is serum cortisol conducted to investigate Addison’s disease?
It is conducted in primary care, where the ACTH stimulation test is not readily available
When should serum cortisol levels be measured?
Morning
What serum cortisol level excludes Addison’s disease?
> 500
What serum cortisol level indicates Addison’s disease? What investigation should be conducted to confirm a diagnosis?
< 500
ACTH stimulation test
What ABG feature indicates Addison’s disease?
Metabolic acidosis
What is another term for the ACTH stimulation test?
Short Synacthen test
What is the gold standard investigation of Addison’s disease?
ACTH stimulation test
What is the ACTH stimulation test?
It involves the patient’s initial cortisol and ACTH levels being measured – ideally in the morning
We then inject the patients with IM tetracostartin, which is synthetic ACTH
Following administration, the cortisol levels are remeasured at 30 and 60 minutes
What is a normal ACTH stimulation test result? Explain this
Increased cortisol levels at 30 - 60 minutes - usually to > 450
The synthetic ACTH administration will stimulate production of cortisol levels
What ACTH stimulation test result indicates Addison’s disease? Explain this
Decreased cortisol levels at 30 and 60 minutes
The synthetic ACTH administration will fail to stimulate the production of cortisol levels
How is the ACTH stimulation test used to differentiate between Addison’s disease and other causes of adrenal insufficiency?
Plasma ACTH levels
What plasma ACTH levels in the ACTH stimulation test indicate Addison’s disease? Explain
Increased plasma ACTH levels
This is due to the fact that Addison’s disease is a primary cause of hypoadrenalism, and therefore ACTH levels are elevated to stimulate cortisol production
What plasma ACTH level in the ACTH stimualtion test indicates secondary adrenal insufficiency? Explain this
Decreased plasma ACTH levels
This is due to the fact that pituatary dysfunction results in inadequate ACTH levels stimualting the adrenal glands
How are MRI scans used to investigate Addison’s disease?
They are used to exclude other causes of adrenal insufficiency, such as adrenal tumours, haemorrhage or structural pathology
What are the two pharmacological management options of Addison’s disease?
Hydrocortisone
Fludrocortisone
When is hydrocortisone used to manage Addison’s disease?
It is the first line management option, alongside fludrocortisone
How is hydrocortisone used to manage Addison’s disease?
It is used to replace glucocorticoids – cortisol
How do we administer hydrocortisone - in terms of dosage?
In most cases, individuals require 20 – 30 mg of hydrocortisone daily, which is administered in two divided doses per day - morning and evening
What hydrocortisone dose is greater - morning or evening? Why?
The morning dose is usually greater than the evening dose
This is to mimic the normal 24 hour fluctuation of cortisol levels
What should all Addison’s disease patients be administered to treat adrenal crisis?
Hydrocortisone injections with needles and syringes
When is fludrocortisone used to manage Addison’s disease?
It is the first line management of Addison’s disease, alongside hydrocortisone
How is fludrocortisone used to manage Addison’s disease?
It is used to replace mineralocorticoids – aldosterone
How do we administer fludrocortisone - in terms of dosage?
In most cases, individuals require 50 – 300 mg of fludrocortisone daily, which is adjusted according to their clinical status, U&Es and plasma renin level
What should all Addison’s disease patients wear at all times? Why?
MedicAlert bracelets and steroid cards
This is to allow emergency services to quickly identify their steroid dependency
How is pharmacological management adjusted in Addison’s disease when individuals are ill?
We advise them that their glucocorticoid dose should be doubled, with the fludrocortisone dose remaining the same
This is to match the normal steroid response
How is pharmacological management adjusted in Addison’s disease when individuals are ill - with vomiting?
They should administer IM corticosteroids until the vomiting stops
What is a complication of Addison’s disease?
Addisonian Crisis
What is addisonian crisis?
It is defined as a life threatening deterioration of Addison’s disease, in which there is significantly reduced steroid levels
What are the four causes of addisonian crisis?
Sepsis
Surgery
Adrenal Haemorrhage (Waterhouse-Friderichsen Syndrome)
Steroid Withdrawal
What are the four clinical features associated with Addisonian crisis?
Confusion
Severe Weakness
Delirium
Hypotension
What are the three management options of addisonian crisis?
IM/IV 100mg Hydrocortisone 6 Hrly Until Stable
IL Normal Saline Infused 30 – 60 Minutes
Dextrose Infusion If Hypoglycaemia
What is primary adrenal insufficiency?
It is defined as adrenal gland dysfunction leading to direct reduced cortisol and aldosterone levels
What are the eight other causes of primary adrenal insufficiency?
Tuberculosis
HIV
Meningococcal Sepicaemia
Renal Cancer
Lung Cancer
Breast Cancer
Antiphospholipid Syndrome
Postadrenalectomy
What is another term for meningococcal septicaemia?
Waterhouse-Friderichsen syndrome
What is secondary adrenal insufficiency?
It is a result of pituatary gland dysfunction resulting in inadequate ACTH stimulating the adrenal glands
This results in reduced cortisol levels ONLY
What are the three causes of secondary adrenal insufficiency?
Pituatary Adenoma
Sheehan’s Syndrome
Steroids
What clincial feature differentiates between primary and secondary adrenal insufficiency?
Hyperpigmentation
It is only present in primary adrenal insufficiency
