Chemical Pathology - Adrenals

Question 1

What are the different layers of the adrenal cortex and what do they produce?

Answer 1

GFR
1. Glomerulosa
- Mineralocorticoid (e.g. aldosterone)
2. Fasciculata
- Corticosteroid (e.g. cortisol)
3. Reticularis
- Sex steroids

Question 2

Where does Steroid production occur?

Answer 2

In the adrenal cortex

Question 3

What are some causes of Addison’s disease and which are most common?

Answer 3

• Autoimmune (most common in Europe)
• TB (most common worldwide)
• Tumour mets
• Adrenal haemorrhage (meningococcus)
• Amyloidosis

Question 4

What happens to the adrenal cortex in Addison’s disease?

Answer 4

Antibodies attack the adrenal cortex, causing hypoaldosteronism

Question 5

What are some signs and symptoms of Addison’s disease?

Answer 5

Signs:
- Increase potassium
- Decreased sodium
- Postural hypotension

Sx:
- Skin pigmentation
- Lethargy
- Depression
- Vomiting (from hyperkalaemia)
- Decreased arm + pubic hair

Can progress to Addisonian Crisis

Question 6

What investigations are used to diagnose Addison’s Disease?

Answer 6

Short SynACTHen Test

(+ 9am cortisol)

Question 7

What is the treatment of Addion’s Disease?

Answer 7

Hormone replacement
- Hydrocortisone OR fludrocortisone if primary adrenal lesion

Question 8

What are some causes of Cushin’s Syndrome and which are most common?

Answer 8

ACTH-dependent:
- Pituitary tumour (Cushing’s Disease) = 85%
- Ectopic ACTH-producing tumour (e.g. small cell lung cancer, carcinoid tumour) = 5%

ACTH-independent:
- Adrenal adenoma = 10%
- Adrenal nodular hyperplasia
- Iatrogenic
- Steroid-use

Question 9

What are some signs and symptoms of Cushing’s Syndrome?

Answer 9

Signs:
- HTN
- Central Obesity
- Moon face
- Buffalo hump

Sx:
- Striae
- Acne
- Diabetes
- Muscle weakness (proximal myopathy)
- Hirsutism
- Bruising
- Amenorrhoea

Question 10

What are the investigations for diagnosing Cushing’s Syndrome?

Answer 10

1. Overnight Dexamethasone suppression test OR 24hr urinary free cortisol (+ve = Cushing’s)
2. Low dose (0.5mg) or High dose (2mg) dexamethasone suppression test
   - Low dose fails to suppress cortisol in all causes
   - High dose succeeds to suppress in Pituitary Cushing’s (Cushing’s Disease)
3. CT/PET (identifies ectopic source of ACTH)

Question 11

What is the treatment for Cushing’s Syndrome?

Answer 11

Treat underlying cause

Cushing’s Disease = Transphenoidal resection

Question 12

What is the commonest cause of hyperaldosteronism?

Answer 12

Bilateral idiopathic hyperplasia of adrenal cortex

Question 13

What is the cause of Conn’s syndrome?

Answer 13

Adrenal adenoma

Question 14

What are some signs and symptoms of Conn’s syndrome?

Answer 14

• Uncontrollable hypertension
• Increased Sodium
• Decreased Potassium
• Polyuria
• Polydipsia

Question 15

How is Conn’s Syndrome diagnosed?

Answer 15

Raised Aldosterone:Renin ratio

Question 16

What is the management of Conn’s Syndrome?

Answer 16

Aldosterone antagonists/potassium sparing diuretics (e.g. spironolactone, eplerenone, amiloride)

IF >4cm, ?surgical excision

Question 17

What is the cause of a phaeochromocytoma?

Answer 17

Adrenal medullar tumour causing an increase in adrenaline

Question 18

What are the signs and symptoms of a phaeochromocytoma?

Answer 18

TRIAD:
- Headaches
- HTN
- Hyperhidrosis

• Arrhythmias
• Death (if untreated)

Question 19

How is a phaeochromocytoma diagnosed?

Answer 19

• Plasma + 24hr urinay metanephrines/catecholamines + VMA
• CT abdo

Question 20

What is the management of a phaeochromocytoma?

Answer 20

1. Α blockade (Phenoxybenzamine)
2. Β blockade
3. Surgery (when BP controlled)

Question 21

What is Waterhouse Friderichson Syndrome and how is it caused?

Answer 21

An infection/septicaemia picture causing haemorrhagic infarcts in the adrenal glands

• Caused by meningococcal septicaemia

Question 22

What are the Autoimmune Polyendocrine Syndromes (AIPE 1+2):

Answer 22

1 = Adrenal insufficiency + hypoparathyroidism
2 = Adrenal insufficiency + Hypothyroidism (Schmidt’s Syndrome)

Question 23

What is Schmidt’s syndrome?

Answer 23

Autoimmune polyendocrine syndrome 2
(Adrenal insufficiency + hypothyroidism)