66 - Diagnosis of Adrenal Disorders

Question 1

Structure of all steroids (including aldosterone and cortisol)

Answer 1

Four ring structure

Question 2

Alternative name for cortisol

Answer 2

Hydrocortisone

Question 3

Cortisone

Answer 3

Biologically-inactive metabolite of cortisol.

Metabolised in the liver back into cortisol.

Question 4

Three main synthetic pathways of steroids

Answer 4

1) Sex hormones
2) Mineralocorticoids (EG aldosterone)
3) Glucocorticoids (EG cortisol)

Question 5

Actions of glucocotricoids
1
2
3
4

Answer 5

• Stimulation of gluconeogenesis (liver)
• Mobilisation of amino acids (muscle)
• Stimulation of lipolysis (adipose tissues)
• Immunosuppression

Question 6

Effects of too much cortisol
1
2
3
4
5

Answer 6

· Weight gain
· Wasting of muscle, skin and bone
· Hyperglycaemia (muscle amino acid → glucose)
· Hypertension (salt retention)
· Inhibition of linear growth

Question 7

Two forms of hypercortisolism

Answer 7

1) ACTH dependent

2) ACTH independent

Question 8

ACTH dependent hypercortisolism common causes
1
2

Answer 8

– Pituitary adenoma (“Cushing’s disease”)

– Ectopic ACTH syndrome

Question 9

ACTH-independent hypercortisolism common causes
1
2
3

Answer 9

– Adrenal adenoma or carcinoma
– ACTH-independent nodular hyperplasia
– Administration of glucocorticoids (common side effect of treatment)

Question 10

Most common cause of hypercortisolism

Answer 10

Taking exogenous glucocorticoids

Question 11

Cushing’s disease
2
3
4

Answer 11

Hyperadrenocortisolism
Leads to:
– hypertension
– apparent obesity
– muscle wasting, thin skin, metabolic derangements
(eg. diabetes)

Question 12

Symptoms of Cushing's disease (in descending order of incidence)
1
2
3
4
5
6
7
8
9
10

Answer 12

Moon face (with red cheeks)
Obesity 
Hypertension
Menstrual disorders
Hirsutism (in females)
Weakness (leads to thin arms and legs)
Easily bruised
Osteoporosis
Ankle oedema
Buffalo hump
Acne

Question 13

Basic manner in which hormone tests are carried out

Answer 13

1. Biochemical Testing first then radiology
2. Repeat the test
3. Do not measure random hormones
   - hormone and trophic hormone
   - stimulation if underactive
   - suppresion if overactive
   - regulated reagent and hormone (ca/PTH), glc/insulin
   - 24hr urine assay

Question 14

Investigation of suspected Cushing's
1
2
3
4

Answer 14

• 24h urine free cortisol
• Check diurnal variation: serum cortisol & plasma ACTH at 0800 and midnight
• Check that negative feedback loop is working: dexamethasone suppression test (cortisol, ACTH should drop with administration of dexamethasone)
• Cranial MRI/ adrenal CT as indicated

Question 15

Disease of low cortisol

Answer 15

Addison’s disease

Question 16

Symptoms of Addison's disease
1
2
3
4
5
6

Answer 16

· GI symptoms (anorexia, nausea, vomiting, diarrhea, weight loss)
· Low blood pressure (salt wasting)
· Darkening of the skin (if ACTH secretion is stimulated, as affects melanocytes)
· Muscle weakness (both skeletal and cardiac muscle)
· Increased susceptibility to infection
· Death

Question 17

Causes of adrenal insufficiency

1-4

Answer 17

• Genetic: Enzyme defect in cortisol biosynthesis
• Genetic: metabolic defect: adrenoleukodystrophy
• Autoimmune adrenal destruction (most common cause)
• Infectious disease: adrenal destruction by tuberculosis (other countries)

Question 18

Very dangerous effect of Addison’s disease

Answer 18

Salt-wasting state results in low serum sodium and high serum potassium. Can lead to arrhythmias

Question 19

Location of Addison’s pigmentation

1-4

Answer 19

• Knuckles of hands
• Knees
• Gums & oral mucosa
• General pigmentation

Question 20

Cause and effects of congenital adrenal hyperplasia
1
2
3
4
5

Answer 20

• Due to 21-hydroxylase deficiency in 90% of cases
• Autosomal recessive
• Variable impairment of cortisol and aldosterone biosynthesis
• Prenatal ACTH stimulation → adrenal hyperplasia
• ↑androgen → virilisation

Question 21

CAH effects in males
1
2

Answer 21

• Adrenal crisis in a baby aged 2-3 weeks
OR
• Premature sexual development at age 2-3 years

Question 22

Treatment for CAH

Answer 22

Give cortisol early (get negative feedback)

Question 23

Glucocorticoids (clinical), in order of least to most potent
1
2
3

Answer 23

1) Cortisol/cortisone
2) Prednisolone
3) Dexamethasone

Question 24

Activity of cortisol and cortisone

Answer 24

Have equal mineralocorticoid and glucocorticoid activity

Question 25

Effects of aldosterone

Answer 25

Causes K+ loss (excretion into the kidney distal tubule), Na+ and water retention.

Question 26

Main stimulus for aldosterone release

Answer 26

Salt and water deficit

Question 27

Effect of excessive aldosterone
1
2

Answer 27

1) Hypertension (Na+ retention)

2) Weakness (hypokalaemia)

Question 28

Effect of deficient aldosterone
1
2

Answer 28

1) Dehydration, salt depletion & postural hypotension.

2) Cardiac arrhythmias (hyperkalaemia)

Question 29

What would someone die of if the adrenals were removed?

Answer 29

No aldosterone

Question 30

Syndrome of excessive aldosterone 
1
2
3
4

Answer 30

Conn’s syndrome
• Adrenocortical tumour secreting aldosterone
• Present with hypertension or with weakness due to low potassium
• High sodium, low potassium, low renin
• Cured by surgery

Question 31

Name for primary tumours of the adrenal medulla

Answer 31

Pheochromocytoma