Hyperthyroidism in children: all the information 2026

Lathyroid is a small gland located under the skin and muscles, found in the front and lower part of the neck. It has a shape similar to the bow of a tie, it wraps around the trachea (near the most important nerves for the voice), and it has a brownish red color, with two lobes - left and right halves -, reminiscent of the shape of a butterfly's wings.

Despite its small size, it is actually a tremendously important gland for our body, since it is responsible for both producing and releasing the different thyroid hormones, T3 or triiodethyronine and T4 or thyroxine, which are involved in the regulation of metabolism, growth and the maintenance of most of the body's functions.

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Although different diseases can affect it, when the gland becomes overactive, releasing too much thyroid hormone into the bloodstream, it is known as hyperthyroidism. Which, finally, means that the body consumes energy much faster than it really should, and the chemical activity - such as metabolism - present in the cells ends up speeding up excessively.

What is hyperthyroidism and what are its causes?

When hyperthyroidism exists, it means that the thyroid gland produces too much thyroid hormone. Thus, when a child or person is diagnosed with this condition, it means that the gland has become overactive, pushing the body's metabolism to unhealthy levels. Ultimately, the thyroid produces a greater amount of thyroid hormone, much more than the body actually needs.

Given that one of the main functions of thyroid hormones is to help control metabolism (that is, the speed at which the body carries out different processes, such as the heartbeat), when the body has too much, its excess can end up accelerating these processes, and cause the different symptoms that arise when there is hyperthyroidism, such as weight loss for no apparent reason and nervousness.

One of the most common causes of hyperthyroidism is Graves' disease, an autoimmune disorder. Although it is true that children can develop it, it is known that it is less common in children than in adults.

What are your symptoms?

We must keep in mind that thyroid hormone tends to affect almost all cells and tissues in our body, since it controls a wide variety of metabolic processes. For example, it influences growth, mental development and the body's energy.

Therefore, when the thyroid becomes overactive, and produces or releases too much thyroid hormone, the body's processes accelerate and end up affecting: breathing, brain development, functions of both the nervous system and the heart, body temperature, weight, cholesterol, menstrual cycles and the skin.

On the other hand, the symptoms vary depending on the stage in which the child is.

Symptoms of hyperthyroidism in newborns:

• Rapid heartbeat.
• Goiter (enlarged thyroid gland).
• Irritability.
• Bulging eyes.
• Poor weight gain.

Symptoms of hyperthyroidism in children and adolescents:

• Irritability, anxious nervousness.
• Poor weight gain, or weight loss.
• Increased energy (or hyperactivity).
• Trembling of the hands.
• Rapid heartbeat.
• High blood pressure.
• Bulging eyes.
• Enlarged thyroid gland.
• Diarrhea.

How is hyperthyroidism in children diagnosed?

On the first visit, the endocrinologist is the specialist who will be in charge of analyzing the child's medical history and, in addition, carrying out a physical examination of the child. Later, you may need a blood test to determine how much thyroid-stimulating hormone is in your bloodstream. This test is tremendously useful, since it is capable of detecting the presence of even mild hyperthyroidism.

Sometimes there may be a need to perform other tests, such as measuring levels of T4 (thyroxine) or T3 (triiodothyronine), or searching for an antibody known as thyroid-stimulating immunoglobulin, when the possible existence of Graves' disease is suspected.

What are its causes and how is it treated?

Almost all cases of hyperthyroidism diagnosed in children and adolescents are caused by Graves' disease. Although it is true that, among children, hyperthyroidism tends to be diagnosed more frequently in adolescents.

There are also other related causes, such as: thyroiditis (inflammation of the thyroid), thyroid nodules, treatment for underactive thyroid (excessive iodine consumption and overmedication with synthetic thyroid hormone). Although they are actually rare causes.

In newborns, hyperthyroidism occurs when a thyroid-stimulating antibody passes through the placenta from the mother who has or had Graves' disease. In this case, it is a type of transient hyperthyroidism, requiring medication for only a few months, so it is a very treatable condition.

However, medical treatment varies depending on the age of the child, and the presence - or not - of other medical conditions or diseases. So hyperthyroidism can be treated in different ways.

For example, antithyroid medication can be administered, which are drugs taken continuously and daily. Thyroidectomy is surgery in which all or part of the thyroid gland is removed. Or, radioactive iodide ablation, which is a procedure that prevents the thyroid from producing too much thyroid hormone.

Generally, medical treatment begins with the administration of an antithyroid drug, which is capable of slowing down the production of thyroid hormone. It can be taken once or twice a day, and hormone levels usually return to the normal range within a few weeks or months, although the average time is actually between one to two years.