Paediatric Thyroid

Question 1

Q: What happens to thyroid levels at birth?

Answer 1

A:

1- A small amount of thyroxine is transferred from mother to fetus.

2- After birth, there is a surge in TSH, leading to a marked rise in T3 and T4 levels.

3- TSH levels decline to normal adult ranges within a week.

Question 2

Q: What are the main causes of congenital hypothyroidism?

Answer 2

1- Maldescent of the thyroid – lingual mass or unilobular gland.

2- Athyrosis – incomplete or absent development of the thyroid.

3- Dyshormonogenesis – errors in thyroid hormone synthesis (linked to consanguinity).

4- Iodine deficiency – rare in the UK, prevented by iodinated salt in maternal diet.

5- TSH deficiency – associated with panhypopituitarism.

Question 3

Q: What are the clinical features of congenital hypothyroidism?

Answer 3

Failure to thrive
Difficulty feeding
Constipation
Prolonged jaundice
Large tongue
Hoarse cry
Umbilical hernia
Coarse facies
Delayed development

Question 4

Q: How is congenital hypothyroidism treated?

Answer 4

• Oral levothyroxine started within 14 days of age (or by 21 days if repeat test required).
• Starting dose: 15-20 mcg/kg/day (max 50 mcg/day).
• Aim: Increase T4 levels and normalize TSH within the first month.
• Regular monitoring of TSH and T4 levels for dose adjustments.

Question 5

Q: What is juvenile hypothyroidism, and how does it present?

Answer 5

• Usually autoimmune and more common in females.
• Symptoms: Growth failure, delayed puberty, reduced bone age, cold intolerance, bradycardia, goitre, dry skin, constipation, and obesity.
• Treated with levothyroxine.

Question 6

Q: What is the most common cause of hyperthyroidism in children?

Answer 6

Grave’s disease.

Question 7

Q: How is hyperthyroidism treated in children?

Answer 7

• Carbimazole for 2-3 years, then stopped.
• Relapses managed with a second course of drugs or thyroid gland removal.

Question 8

Q: What causes neonatal hyperthyroidism?

Answer 8

Trans-placental transfer of Thyroid Stimulating Immunoglobulins (TSI) from mothers with Grave’s disease.

Question 9

Q: What are the signs of neonatal thyrotoxicosis?

Answer 9

Tachycardia (>160 bpm)
Jitteriness
Diarrhoea and vomiting
Sweating
Tachypnoea (>60 breaths/min)
Periorbital oedema or exophthalmos
Goitre
Hypertension and arrhythmias

Question 10

Q: How is neonatal hyperthyroidism managed?

Answer 10

• Babies born to mothers with Grave’s disease are placed on an enhanced surveillance pathway:
• Observation on postnatal ward for 24 hours.
• Review by a community midwife on day 5-7 (TFTs and FBC done).
• Paediatric review on day 10-14 (TFTs and FBC repeated).
• Discuss abnormal results with a Paediatric Endocrinologist for potential treatment.