Sesh 9- Adrenal Glands and Disorders

Question 1

Why do patients with Cushing’s syndrome have purple striae?

Answer 1

• Increased cortisol causes redistribution of fat to the abdomen, stretching the skin
• Cortisol causes proteolysis…the skin is weaker

Question 2

Why do patients with Addison’s disease get skin hyper pigmentation?

Answer 2

• Reduced cortisol means loss of negative feedback on anterior pituitary
• More of ACTH precursor POMC produced, so more MSH to activate melanocortin receptors on melanocytes, to increase melanin synthesis
• Increased ACTH- can also activate melanocytes

Question 3

What is the most common cause of primary hyperaldosteronism?

Answer 3

Bilateral adrenal hyperplasia

Question 4

What is Conn’s syndrome?

Answer 4

Primary hyperaldosteronism due to an Aldosterone-secreting adrenal adenoma

Question 5

How would you distinguish between primary and secondary hyperaldosteronism?

Answer 5

Via the aldosterone:renin ratio

• Primary- high
• Secondary- low

Question 6

How would you treat hyperaldosteronism?

Answer 6

• Surgery if caused by tumour

- Spironolactone

Question 7

What is Cushing’s syndrome?

Answer 7

Chronic excessive exposure to cortisol

Question 8

Name the 2 ACTH-dependent cause of Cushing’s syndrome.

Answer 8

1. Cushing’s disease- benign pituitary adenoma

2. Ectopic ACTH produced by tumour e.g. small cell tumour of lung

Question 9

In which syndrome/disease would patients have a high blood pressure with hypokalaemia?

Answer 9

Cushing’s syndrome

Question 10

What is Addison’s disease?

Answer 10

Chronic adrenal insufficiency most commonly caused by autoimmune destruction of the adrenal cortex

Question 11

How would you treat Cushing’s syndrome caused by long-term steroid use?

Answer 11

GRADUALLY reduce their steroid dosage

Question 12

Why would sudden steroid withdrawal be dangerous?

Answer 12

Can lead to Addisonian crisis, as steroids deplete ACTH stores.

Question 13

What would a low serum cortisol with high ACTH indicate?

Answer 13

Addison’s disease

Question 14

How would you treat an Addisonian crisis?

Answer 14

• Fluid replacement

- IV hydrocortisone

Question 15

What are the general effects of cortisol in the body?

Answer 15

• Catabolic- increased proteolysis, lipolysis
• Anti inflammatory
• Glucose sparing
• Increased glycogen storage
• Re-distribution of fat

Question 16

What are some classic signs of Cushing’s syndrome?

Answer 16

• Moon face
• Buffalo hump (fat in dorso-cervical fat pad)
• Purple abdominal striae

Question 17

Where in the adrenal glands are glucocorticoids produced?

Answer 17

The zona fasciculate of the adrenal cortex

Question 18

Where in the adrenal glands are mineralocorticoids produced?

Answer 18

The zona glomerulosa of the adrenal cortex

Question 19

Which part of the adrenals produce catecholamines?

Answer 19

Adrenal medulla

Question 20

What does the zona reticularis of the adrenal cortex produce?

Answer 20

Androgens (sex steroid hormones)

Question 21

How do steroid hormones exert their effects on cells?

Answer 21

• Diffuse through plasma membrane
• Bind to nuclear receptors
• Modulate gene transcription

Question 22

How is most aldosterone transported in plasma?

Answer 22

Bound to serum albumin

Question 23

How is most cortisol transported in plasma?

Answer 23

Bound to transcortin

Question 24

Name 2 common steroids

Answer 24

• Prednisolone

- Dexamethasone

Question 25

Which enzyme converts NA to Adrenaline in chromaffin cells?

Answer 25

N-methyl Transferase

Question 26

What is a phaeochromocytoma?

Answer 26

Tumour of chromaffin cells in the adrenal medulla

Question 27

In which disease would patient ACTH levels be increased, and cortisol levels be suppressed by a Dexamethasone suppression test?

Answer 27

Cushing’s disease

Question 28

In which disease would patients have a ‘flat’ synacthen response?

Answer 28

Addison’s-chronic adrenal insufficiency

Question 29

In which disease would 9am basal cortisol levels be low?

Answer 29

Addison’s

Question 30

At what time would you do a cortisol test if testing for Cushing’s syndrome, and how is this different if testing for Addison’s disease?

Answer 30

• Test at midnight for Cushing’s (cortisol should be at lowest but will be high if have Cushing’s)
• Test at 9am for Addison’s (cortisol should be at highest, but will be low if have Addison’s)

Question 31

Which enzyme is deficient in patients with congenital adrenal hyperplasia (CAH)?

Answer 31

21-hydroxylase

Question 32

What are steroid hormones synthesised from?

Answer 32

Cholesterol

Question 33

What are catecholamines synthesised from?

Answer 33

Tyrosine

Question 34

What other state are the symptoms of phaeochromocytoma indistinguishable from?

Answer 34

Panic attack

Question 35

Why do patients with Cushing’s syndrome have thin arms and legs?

Answer 35

Excess cortisol causes muscle proteolysis and fat redistribution

Question 36

Why are patients with Cushing’s more susceptible to bacterial infections?

Answer 36

Cortisol has a general anti-inflammatory and immunosuppressive effect

Question 37

Name some disorders steroids are commonly prescribed for.

Answer 37

• Asthma
• Irritable bowel disease
• RA
• Dermatological conditions except acne
• Organ transplant patients

Question 38

Why can cortisol have mineralocorticoid and androgenic effects?

Answer 38

Steroid receptors have have relatively high sequence homology, so at high levels, cortisol can bind mineralocorticoid and androgen receptors.

Question 39

A normal response to the synacthen test excludes what diagnosis?

Answer 39

Addison’s disease

Question 40

Why does Cushing’s cause hypertension?

Answer 40

Excess cortisol can’t all be converted to cortisone. So cortisol acts on renal mineralocorticoid R to exert effects the same as Aldosterone.

Question 41

How can excess liquorice cause secondary hypertension?

Answer 41

Inhibits the enzyme that converts cortisol to cortisone in the kidney. This means there is excess cortisol present, which then activates the mineralocorticoid R.

Question 42

What are the effects of Aldosterone on the kidney?

Answer 42

• Increases Na and H2O reabs, by increasing no of ENaC, Na/K ATPase
• Increases K secretion by up-regulating ROMK channels