Hypothyroidism in Children

Question 1

Causes of hypothyroidism in children?

Why is it important?

Answer 1

Hypothyroidism in children can be congenital or acquired. Thyroid hormone is essential for the development and functioning of the brain and body. Undiagnosed hypothyroidism can lead to significant problems with neurodevelopment and intellectual disability.

Question 2

Congenital hypothyroidism?
Causes?
How does it present?

Answer 2

Congenital hypothyroidism is where the child is born with an underactive thyroid gland. This occurs in around 1 in 3000 newborns. It can be the result of an underdeveloped thyroid gland (dysgenesis) or a fully developed gland that does not produce enough hormone (dyshormonogenesis). Very rarely it can be the result of a problem with the pituitary or hypothalamus. This usually occurs without any other problems and the cause is not clear.

Congenital hypothyroidism is screened for on the newborn blood spot screening test. Where it is not picked up a birth, patients can present with:

Prolonged neonatal jaundice
Poor feeding
Constipation
Increased sleeping
Reduced activity
Slow growth and development

Question 3

Acquired hypothyroidism?
Cause?
How does it present?

Answer 3

Acquired hypothyroidism is where a child or adolescent develops an underactive thyroid gland when previously it was functioning normally.

The most common cause of acquired hypothyroidism is autoimmune thyroiditis, also known as Hashimoto’s thyroiditis. This causes autoimmune inflammation of the thyroid gland and subsequent under activity of the gland. It is associated with antithyroid peroxidase (anti-TPO) antibodies and antithyroglobulin antibodies. There is an association with other autoimmune conditions, particularly type 1 diabetes and coeliac disease.

This can lead to symptoms of:

Fatigue and low energy
Poor growth
Weight gain
Poor school performance
Constipation
Dry skin and hair loss

Question 4

Diagnosis + management of hypothyroidism in children?

Answer 4

Investigations include full thyroid function blood tests (TSH, T3 and T4), thyroid ultrasound and thyroid antibodies.

Levothyroxine orally once a day is used to replace the normal thyroid hormones. Doses are titrated based on thyroid function tests and symptoms.