Endocrine Problems in Children

Question 1

What can cause congenital hypothyroidism in children?

Answer 1

Congenital - these can be athyreosis, thyroid dysgenesis and dyshormonogenesis. Also maternal anti thyroid drugs such as propylthiouracil

Question 2

What can cause acquired hypothyroidism in children?

Answer 2

Acquired - prematurity, Hashimoto’s thyroiditis, hypopituartism and trisomy 21

Question 3

What are the clinical features of hypothyroidism in children?

Answer 3

Prolonged jaundice
Widely open posterior fontanelle
Poor feeding
Hypotonia
Dry skin
Inactivity, sleepiness, slow feeding, little crying and constipation
Coarse dry hair, flat nasal bridge, protruding tongue, umbilical hernia, slowly relaxing reflexes, bradycardia, poor growth and mental development.

Question 4

What investigations should be done in suspected hypothyroidism in children?

Answer 4

Screened for in the heel prick test in the Guthrie card
Low T4, high TSH
Test bone age against chronological age using x-ray of wrist and hand

Question 5

How is hypothyroidism managed in children?

Answer 5

Levothyroxine

Adult doses by 12 years

Question 6

What is the classic presentation of hyperthyroidism in children?

Answer 6

Classic presentation
Pubertal girl
Palpitation and tremor
Anxiety and tachycardia

Question 7

What investigations should be done in suspected hyperthyroidism in children?

Answer 7

Low TSH high T4

Fine needle aspiration of goitre

Question 8

How is hyperthyroidism managed in children?

Answer 8

Carbimazole

Propylthiouracil

Question 9

What is precocious puberty?

Answer 9

Puberty can start as early as 8yrs in girls and 9yrs in boys

If onset is earlier than this then refer to paediatric endocrinologist (10:1 female and male)

Question 10

Which specific physical signs of puberty equate to specific endocrine events?

Answer 10

Enlargement of testes = pulses of pituitary gonadotrophin
Breast and penis enlargement = gonadal sex steroids
Pubic hair = adrenal androgen production
Male growth spurt = tests volume reaching 10-12ml
Female growth spurt = after breast development
Menarche = stage 4 breast development

Question 11

What are the 2 classifications of precocious puberty?

Answer 11

Gonadotrophin dependent (central/true) and
• Due to premature activation of the hypothalamic-pituitary-gonadal axis
• FSH & LH raised
• Testes enlarged

Gonadotrophin independent (pseudo/false)
• Due to excess sex hormones
• FSH & LH low
• Testes may be small or unilaterally enlarged (Leydig cell tumour)

Question 12

What is usually the cause of precocious puberty in boys?

Answer 12

Males - uncommon and usually has an organic cause which are rare, associated with rapid onset, neurological symptoms, signs and dissonance. Examples of organic causes
• CNS lesions: craniopharyngioma, hydrocephalus, neuro fibroma and tuberous sclerosis
• hCG secreting hepatoblastoma
• primary hypothyroidism (increased TSH stimulates FSH receptors)

Question 13

How should suspected precocious puberty be investigated?

Answer 13

Tanner staging
Growth charts
Bone age from skeletal survey
Karyotyping
Thyroid function
Adrenal function

Question 14

How is precocious puberty managed?

Answer 14

Synthetic GnRH analogues
Note this will not reverse pubic hair as it won’t affect adrenal cortex
Anti androgens such as flutamide and spironolactone

Question 15

What controls sex development in humans?

Answer 15

Sexual development is controlled by the presence or absence of the SRY region on the Y chromosome. SRY regions triggers a series of events that results in the release of testosterone and anti-Mullerian hormone leading to male genitalia. Ambiguous gender at birth is an emergency for the family and well being of wider family.

Question 16

What causes ambiguous genitalia?

Answer 16

Exposure to progesterone, testosterone, phenytoin and aminoglutethimide
Genetic abnormalities e.g. 10q terminal deletion – region required for male development

Question 17

How should ambiguous genitalia at birth be investigated and managed?

Answer 17

Visual inspection – penis size and urethra position, are the labia fused, is there a vaginal opening, have the gonads descended
Note preterm girls have relatively prominent labia and clitoris whilst preterm boys have undescended testicles until 34 weeks gestation
Genetic test determination – FISH
Blood tests – electrolytes, glucose, adrenal androgens, LH and FSH
If genitalia are ambiguous do not rely on visual inspection to determine sex

Question 18

What is congenital adrenal hyperplasia?

Answer 18

Caused by a genetic defect in gene for enzyme involved in hormones production. Cortisol inadequately produced leading to rise of CRH, adrenal hyperplasia and an increase in cortisol precursors such as progesterone and consequently increased testosterone. Also issue with aldosterone production so large loss of salt.

Question 19

What are the clinical features of congential adrenal hyperplasia?

Answer 19

Boys – at birth there will be electrolyte imbalance but may also be extra masculinisation and precocious puberty
Girls – masculinisation (antenatal diagnosis possible and allows treatment in utero)
General – vomiting, dehydration and salt loss
Hyponatraemia with paradoxically high Na loss in urine
Hyperkalaemia also common

Question 20

How is congenital adrenal hyperplasia managed?

Answer 20

Glucocorticoid replacement in all patients, mineralocorticoid only in those with salt loss.
Surgical management – clitoral reduction and vaginoplasty.

Question 21

How should an adrenocortical crisis be managed?

Answer 21

May present with circulatory collapse, usually it is an exacerbation brought on by stressors that triggers a life-threatening emergency.
Symptoms – nausea, vomiting, lethargy, hypotension
Management – hydrocortisone, glucose and fludrocortisone.