Paediatric Endocrinology 2

Question 1

Why do you get hypocalcaemia in 22q.11?

Answer 1

Parathyroid aplasia/hypoplasia

Question 2

What is the most common cause for acquired overt hypothyroidism?

Answer 2

• Autoimmune thyroiditis (Hashimoto disease)

- Elevated thyroid peroxidase (TPO) antibody concentration is most consistent with this diagnosis

Question 3

What does aldosterone do?

Answer 3

• Conserves sodium and water

- Decreases potassium

Question 4

Abnormal levels of carrier proteins are most likely to have clinically significant effects on the activity of which hormones?

Answer 4

• testosterone and oestradiol

- mostly bound to sex hormone binding globin, free form = active

Question 5

What is the most likely cause of neonatal hypothyroidism?

Answer 5

Thyroid dysgenesis

Question 6

Premature puberty: female with height >97th centile, tanner 3 breast development, tanner 1 pubic hair, no skin markings, elevated bone age. What is the most likely diagnosis?

Answer 6

• not true precocious puberty as breast development =/= pubic hair development
• elevated bone age/height/breast development, most likely sexual precocity as a consequence of oestrogen secretion therefore ovarian cyst

Question 7

What are you likely to find if you test insulin/ketones in the infant of diabetic mother with hypoglycaemia?

Answer 7

• High insulin (due to newborn being in hyperglycaemic environment)
• Low serum ketones (due to high insulin)
• Negative urinary reducing substances (as not metabolic)

Question 8

The growth promoting effects of Growth Hormone (GH) are mostly mediated by…?

Answer 8

IGF1 (Insulin-like Growth Factor One)

Question 9

What are the most common DM1 autoantibodies?

Answer 9

• Glutamic acid decarboxylase antibody
• GAD is present in islet cells, CNS, testes
• 70% patients with type 1 DM at time of diagnosis

Question 10

Which syndrome is associated with elevated calcium?

Answer 10

Williams

Question 11

What are the typical features of phaeochomocytoma?

Answer 11

• hypertension (may be symptomatic with headache)
• 90% from adrenal medulla, R>L, 6-14yo
• elevated plasma normetanephrine (no caffeine/pamol)
• Episodic sweating, tachycardia, or palpitations
• Abdominal pain or distension, or back pain

Question 12

What is falsely elevated by consumption of vanilla?

Answer 12

Vanillylmandelic acid (3-methoxy-4-hydroxymandelic acid) - hence we don’t use it to look for phaeo!

Question 13

What is Schmidt syndrome?

Answer 13

Association of autoimmune Addison/adrenalitis
WITH
T1DM or thyroiditis
same HLA types as like...coeliac
HLA-DQ2, HLA-DQ8 and HLA-DR4

Question 14

What is the mechanism of action of Leuprorelin acetate?

Answer 14

GnRH agonist

Question 15

Why do we change to glargine insulin?

Answer 15

No peak, less nocturnal hypoglycaemia

Question 16

What happens to your bloods and urine chemistry with cerebral salt wasting?

Answer 16

• Cerebral salt wasting results in a low serum sodium level due to the effect of ANP secretion
• ANP increases renal loss of sodium so urinary Na is HIGH, HIGH urine output->HYPOvolemia
• ANP directly inhibits ADH release so ADH levels are LOW.

Question 17

Which peptide hormone binds directly to intracellular receptors?

Answer 17

T4

Question 18

What happens to your bloods and urine chemistry with central diabetes insipidus?

Answer 18

• HIGH serum sodium
• HIGH urine output so HYPOvolemia
• LOW urine sodium and LOW ADH

Question 19

What is ‘sick day treatment’ for a child with pan-hypo-pit on: hydrocortisone tds, DDAVP BD, thyroxine and GH?

Answer 19

Triple the hydrocortisone, omit the DDAVP and let the child drink freely

Question 20

What factors stimulate and suppress growth hormone?

Answer 20

Suppressed by: glucose, bromocriptine, somatostatin

Stimulated by: insulin, glucagon, exercise, arginine, clonidine, l-dopa

Question 21

What factors stimulate and suppress cortisol level?

Answer 21

Suppress: dex, exogenous steroids
Stimulate: insulin, glucagon, ACTH (synacthen
test), vasopressin