Adrenal Disease

Question 1

In the adrenal medulla, what cells produce what type of catecolamines?

Answer 1

Chromafin cells produce noradrenaline and adrenaline.

Question 2

Name the 3 layers of the adrenal cortex and what they produce.

Answer 2

From Out to In (The deeper you go the sweeter it gets)

1. Zona Glumerulosa (Salt - Mineralocorticoids)
2. Zona Fasciculata (Sugar - Glucocorticoids)
3. Zona Reticularis. (Sex Hormones)

Question 3

Name the 4 main adrenal disorders.

Answer 3

1. Cushings Disease - Increased glucocorticoids.
2. Primary Hyperaldosteronism (Conn’s) - Increased mineralocorticoids.
3. Addison’s disease (Adrenal failure)
4. Phaeochomocytoma (Increased adrenalin)

Question 4

What is the most common cause of Cushing’s disease?

Answer 4

Exogenous cortisol/steroid use.

Question 5

Describe the difference between ACTH dependent and ACTH indepdenet cushing’s syndrome?

Answer 5

1/ Corticotropin-dependent (ACTH dependent) causes account for about 80-85% of cases:

• 80% are due to pituitary adenomas (Cushing’s disease).
• The remaining 20% are due to ectopic corticotropin syndrome, which is usually due to small-cell carcinoma of the lung and bronchial carcinoid tumours, but may occur with almost any endocrine tumour, eg phaeochromocytoma, pancreaticneuroendocrine tumours, medullary thyroid cancer, gut carcinoids.​

​2/ Corticotropin-independent Cushing’s syndrome is most often due to a unilateral tumour: adrenal adenoma in 60% and adrenal carcinoma in 40% of cases.

Question 6

Who should we test for Cushing’s disease?

Answer 6

1. People with multiple fractures
2. Children with low height and increased weight.
3. Unusual features for age (OP, HTN)

Question 7

What are the first line investigations for Cushing’s disease?

Answer 7

1. 24 hour urinary free cortisol (2 samples required)
2. Late night salivary cortisol (2 samples required)
3. Dexamethasone suppression test.

Question 8

What are the treatment options for ACTH dependent and ACTH independent Cushing’s syndrome?

Answer 8

1. ACTH depdenent - Pituitary surgery or treatment for cancerous cause.
2. ACTH independent - unlateral adrenelectomy

Question 9

What is the most common cause of primary hyperaldosteronism (Conn’s syndrome)?

Answer 9

Bilateral adrenal hyperplasia.

Question 10

What electrolyte imbalance occurs in hyperaldosteronism?

Answer 10

High Sodium (salt retention)

Water retention

Low Potassium.

ALSO Low Renin

Question 11

Who should we suspect might have primary hyperaldosteronism?

Answer 11

If they are hypertensive AND

• BP is not responding to 3 agonists.
• Low potassium
• < 40 years.
• Incidental adrenal mass on imaging.

Question 12

How does one investigate for primary hyperaldosteronism?

Answer 12

Aldosterone to Renin Ratio

Take mid morning after patient has been up for atleast 2 hours.

Question 13

In what situations can you get false positives and false negatives in the Aldosterone-to-Renin Ratio?

Answer 13

False positives - methyldopa, clonidine, B-Blockers, NSAIDs.

False negatives - ACE-i, CCB, AR2B, Diuretics.

Switch antihypertensives to Doxazosin or Verapamil whilst test is carried out.

Question 14

What is a phaeochromocytoma?

Answer 14

A neuroendocrine tumour of the chromafin cells.

Question 15

What is a paraganglioma?

Answer 15

Tumour of the sympathetic and parasympathetic tissue in the head and neck. (It can rarely secrete catecholamines)

Question 16

What are some signs and symptoms of a phaeochromocytoma?

Answer 16

Headache, palpitations, Sweating, HTN, Hyperglycaemia.

Symptoms are often transitory and not constant.

Question 17

What investigations can be done when investigating for phaeochromyctoma?

Answer 17

1. 24 hour urinary catecholamine collection
2. Plasma or urinary metanephrines

Plasma metanephrines is most sensitive and specific.

Question 18

Testing for plasma/urinary metanephrines can produce false positives (15% of positive results). Why is this?

Answer 18

Physical stress and a number of drugs may interfere with the assay and cause false elevation of metanephrines. Drugs include tricyclic antidepressants, alcohol, levodopa, labetalol, sotalol, amfetamines, benzodiazepines and chlorpromazine.

Question 19

What age group does Addison’s disease most commonly occur in?

Answer 19

30 to 40 years.

Question 20

What is the most common cause of Addison’s disease worldwide?

Answer 20

Tuberculosis

Question 21

What is the most common cause of Addison’s disease in the developed world?

Answer 21

Autoimmunity.