Adrenal Disease

Question 1

What is the function of aldosterone?

Answer 1

Acts on the mineralocorticoid receptors on the distal tubule and collecting duct causing sodium retention and potassium excretion

Question 2

What is Cushing’s syndrome and what are the causes of it ?

Answer 2

A clinical state produced by chronic glucocorticoid excess from any cause

Causes:
Oral steroids
Endogenous causes
ACTH dependent: conditions that have high ACTH levels (Cushing’s disease, ectopic ACTH production)
ACTH independent: excessive cortisol secretion by adrenal glands despite a suppressed ACTH level (adrenal adenomas, bilateral adrenal hyperplasia)

Question 3

What is Cushing’s disease?

Answer 3

A pituitary tumour secreting ACTH

Question 4

What is the management of Cushing’s disease?

Answer 4

1) Mifepristone (glucocorticoid receptor antagonist) 300mg PO once daily before surgery
2) Transphenoidal pituitary adenectomy
3) Post surgery: hydrocortisone 10-25mg PO in 2-3 divided dose

Question 5

What can often mimick Cushing’s disease?

Answer 5

Alcohol excess

Question 6

What is Addison’s disease?

Answer 6

Destruction of the adrenal cortex causing cortisol and aldosterone deficiency. 80% due to autoimmunity

Question 7

Name some causes of Addison’s disease

Answer 7

Autoimmunity
Adrenal metastases from breast, lung and renal cancer
Tuberculosis
Lymphoma
Secondary: exogenous steroids (suppresses the HPA axis)

Question 8

What are symptoms of Addison’s disease?

Answer 8

Lean, tanned, pigmented palmar creases and buccal mucosa, tired, tearful

Anorexia, unexplained vomiting and abdominal pain

Depression, psychosis

Question 9

What are the investigations of Addison’s disease and what will they show?

Answer 9

Serum electrolytes: low sodium, high potassium

Urea may be elevated

9am serum cortisol (100-500 should prompt a short synacthen test)

Short synacthen test: gold standard, plasma cortisol measured before and after 30mins after giving synacthen 30mg IM

Question 10

What is the management of Addison’s disease

Answer 10

Hydrocortisone 20-30mg per day in 2-3 divided doses
Fludracortisone
If ill, the glucocorticoid dose should be doubled

Question 11

What happens in an Addisonian crisis?

Answer 11

Severe adrenal insufficiency
Causes:
Sepsis or surgery causing an acute exacerbation
Adrenal haemorrhage (Waterhouse-Friedrich syndrome)
Steroid withdrawal

Question 12

What is the management of an Addisonian crisis?

Answer 12

Hydrocortisone 100mg IM or IV

IL normal saline over 30-60 minutes

Question 13

What is a pheochromocytoma?

Answer 13

Tumour of the adrenal medulla, originates in the chromaffin cells. Secretes catecholamines (adrenaline and noradrenaline).

Symptoms: triad: episodic headache, tachycardia, sweating. Also get palpitations and anxiety

Question 14

What are the investigations and treatment of a pheochromocytoma?

Answer 14

Investigations: 24 hour urinary collection to measure metanephrines, abdominal CT/MRI

Treatment: alpha blocker (phenoxybenzamine) and beta blocker (propranolol)

Question 15

What are the primary causes of hyperaldosteronism?

Answer 15

Idiopathic: zona glomerulosa has an increased number of aldosterone secreting cells

Conn’s syndrome: adenoma secreting aldosterone

Familial hyperaldosteronism (genetic)

Question 16

What are the secondary causes of hyperaldosteronism?

Answer 16

Chronic low blood pressure (congestive heart failure, or cirrhosis)
Leads to increased levels of renin
Leads to excess aldosterone production

Question 17

What are the investigations of hyperaldosteronism and what do they show?

Answer 17

1) Aldosterone/renin ratio
2) High resolution CT abdomen following 1)

Electrolytes: hypokalaemia, hypernatraemia
The increased sodium in blood leads to hypertension
Metabolic alkalosis will also occur

Headaches and facial flushing will be seen due to hypernatraemia
Constipation and arrythmias will be seen due to hypokalaemia

Question 18

How do you diagnose primary hyperaldosteronism?

Answer 18

Will show low renin and high aldosterone due to the negative feedback effect

Question 19

How do you diagnose secondary hyperaldosteronism?

Answer 19

High renin and aldosteronism

Question 20

How do you treat hyperaldosteronism?

Answer 20

Potassium sparing diuretics (spironolactone) in particular

Treat underlying cause (e.g. excision of tumour in Conn’s)

Question 21

What occurs in congenital adrenal hyperplasia?

Answer 21

A group of autosomal recessive conditions that affect adrenal steroid synthesis. Low resultant cortisol leads to excess ACTH production by the pituitary, and this stimulates adrenal androgens.

Question 22

What is the main cause of congenital adrenal hyperplasia and what are the features of it?

Answer 22

21-hydroxylase deficiency (90%)

Virilisation in females
Precocious puberty in males 60-70% patients will have a salt losing crisis at 1-3 weeks