Hashimoto Thyroiditis

Hashimoto thyroiditis is another name for the thyroid disorder autoimmune thyroiditis. This is an autoimmune condition in which the body’s immune system — which protects the body against infections — mistakenly attacks and causes inflammation in the thyroid gland. Over time, this inflammation can damage the thyroid so that it can’t produce enough thyroid hormone, which causes hypothyroidism (underactive thyroid). If this happens, your child may need medication to keep their thyroid hormone levels normal. Autoimmune thyroiditis is the most common cause of hypothyroidism in children and adolescents. However, many children with autoimmune thyroiditis have normal thyroid function and do not develop hypothyroidism for many years.

Autoimmune thyroiditis develops slowly and often causes no symptoms early on, especially if thyroid hormone levels remain normal.

Enlargement of the thyroid gland (also known as a “goiter”) can be caused by the inflammation in the thyroid. This enlargement sometimes can be visible or cause discomfort or difficulty swallowing.

If hypothyroidism (underactive thyroid) occurs, other symptoms may include:

• Fatigue
• Constipation
• Dry skin
• Feeling cold
• Irregular or heavy menstrual periods
• Slowed growth
• Hair loss
• Weight gain

Autoimmune thyroiditis is an autoimmune condition in which the body’s immune system mistakenly attacks the thyroid gland, causing inflammation. This inflammation also causes the body to make antibodies that can be detected in the blood, which helps make the diagnosis of autoimmune thyroiditis. Exactly what causes autoimmune thyroiditis is not known. The cause is partly genetic, and autoimmune thyroiditis often runs in families, but often some family members are affected while others are not. It occurs more often in women than in men. It is more common in adults but can occur in children.

To diagnose autoimmune thyroiditis your child’s doctor will discuss your symptoms and do a full exam. They may order blood tests including 

• Thyroid-stimulating hormone level (TSH)
• Free thyroxine level (free T4)
• Thyroid peroxidase antibodies (TPO)
• Thyroglobulin antibodies

The TSH and free T4 levels show how the thyroid is working and whether hypothyroidism (underactive thyroid) is present.

Elevated TPO or thyroglobulin antibodies means that there is autoimmune inflammation in the thyroid. If antibodies are present, that confirms the diagnosis of autoimmune thyroiditis.

An ultrasound of the thyroid usually is not necessary to diagnose autoimmune thyroiditis, but your child’s doctor may order one in some situations.

Children with autoimmune thyroiditis do not always require treatment. Whether treatment is needed depends on whether the disease has caused hypothyroidism (underactive thyroid) and on the specific thyroid hormone levels. Treatment does not depend on the level of thyroid antibodies (TPO or thyroglobulin). These antibodies help diagnose autoimmune thyroiditis, but they do not affect how well the thyroid works.

Here are some possible scenarios:

• If your child’s TSH and free T4 are normal, their thyroid is still working normally and no treatment is needed. There is a risk of developing hypothyroidism in the future, so monitoring of thyroid levels may be needed.
• If your child’s TSH is very elevated (above 10 mIU/L) or if their free T4 is low, treatment usually is needed. A daily medication (levothyroxine) is used to replace the body’s natural thyroid hormone. The dosage is adjusted based on TSH levels in the blood. Since levothyroxine is the same as the body’s natural thyroid hormone, it has no significant side effects.
• If your child’s TSH levels are slightly elevated (below 10 mIU/L) but their free T4 is normal, treatment usually is not needed right away. Monitoring of thyroid hormone levels is needed, and treatment may be necessary in some cases, depending on individual symptoms and how thyroid levels change over time.