Hypothyroidism means the thyroid gland is under-reactive or produces too little thyroid hormone. The most common cause is an autoimmune disorder known as Hashimoto’s thyroiditis, which usually runs in the family and there is nothing that can be done to prevent it.
There are two main types of hypothyroidism. The first is congenital hypothyroidism, which is often diagnosed during mandatory newborn screening tests. One in 2000 - 4,000 babies are born with the disease.
The second is acquired hypothyroidism, which usually appears in adolescence but can happen at any age. One in 2,000 children are diagnosed with the disorder. Hashimoto’s thyroiditis is the most common cause of acquired hypothyroidism.
Symptoms and diagnosis
Babies with hypothyroidism will usually not have any symptoms since it is diagnosed soon after birth with the newborn screening. Older children could experience modest weight gain (between 5-10 lbs.), fatigue, tiredness, constipation, cold intolerance, dry hair and menstrual irregularity. An enlarged thyroid gland could also be visible and can be felt, and a simple blood test can determine if the child has hypothyroidism.
An important thing to note is that while hypothyroidism can cause weight gain, weight gain in itself doesn’t mean the child has a thyroid problem. We know obesity and weight gain can cause mildly abnormal thyroid levels, but it doesn't mean the child needs to be treated. Also, if a child is obese or overweight, but otherwise healthy and growing well, the chances of hypothyroidism are very low.
Treatment is very simple. Children, whether diagnosed with congenital hypothyroidism or acquired hypothyroidism, need to take one pill a day. For babies, the pill can be crushed and put in formula, breast milk or water. There are no side effects of the medication.
Some toddlers with congenital hypothyroidism can be weaned off treatment after 2-3 years old. Children with more severe cases will need to be treated for life. Treatment for acquired hypothyroidism is also lifelong.
Why treatment is important
If not treated, congenital hypothyroidism can cause developmental delays and poor growth in babies. Adolescents and older kids may experience chronic fatigue, constant modest weight gain, poor growth, short stature, mental irregularities and learning difficulties.