Don't Miss Thyroid Disease in Kids

Laurie Scudder, DNP, NP; Andrew Bauer, MD

Disclosures

December 05, 2016

Editorial Collaboration

Medscape &

In This Article

Hyperthyroidism: Less Common, More Often Missed

Medscape: Unlike hypothyroidism, hyperthyroidism is relatively uncommon in kids. However, the incidence is higher in the United States than in the United Kingdom or Ireland. Why is that?

Dr Bauer: This varying incidence is probably due to background genetics combined with environmental factors. Although many people in the United States are of European descent, a wide range of geographic and ethnic backgrounds is represented in this country. There is also a fair degree of ascertainment bias, because the means and accuracy to report the incidence and prevalence is varied. Most countries do not have registries for autoimmune disease and often rely on retrospective review of medical charts from their institute or of national health insurance data.

Differences in incidence between countries may also be partly explained by the hygiene hypothesis, as well as other environmental differences, such as iodine excess or deficiency. The simplified version of the hygiene hypothesis is that children in developed countries have fewer exposures to gastrointestinal parasites and other gastrointestinal infections, which seems to alter the immune system and increase the risk for autoimmune disease. So although there are innumerable advantages to a clean environment, there may be a negative impact on our immune system, leading to an increase in reactivity to autoantigens—self-proteins—with subsequent development of autoimmune diseases, including thyroid disease, type 1 diabetes, rheumatoid arthritis, multiple sclerosis, and the whole family of autoimmune diseases.

Iodine sufficiency may also play a role; some data suggest that iodine excess may have a similar impact, with a subsequent increased risk for autoimmune disease. This concern may be most significant in Asian cultures and countries; however, it is also a reason for persons seeking improved thyroid health and function to avoid taking excess supplemental iodine.

Medscape: You note that although children with Graves disease, the most common cause of hyperthyroidism, are indeed symptomatic—often with restlessness, fidgetiness, and anxiety—the diagnosis is often delayed because these findings are falsely attributed to other conditions. Can you discuss the key findings that would suggest an endocrine etiology, and hopefully lessen this delay?

 
In school-age children and teenagers, the two conditions most likely to be associated with a delay in the diagnosis of hyperthyroid disorder are attention-deficit/hyperactivity disorder (ADHD) and anxiety disorders.
 

Dr Bauer: In school-age children and teenagers, the two conditions most likely to be associated with a delay in the diagnosis of hyperthyroid disorder are attention-deficit/hyperactivity disorder (ADHD) and anxiety disorders. These neuropsychiatric disorders are very common.

Younger patients (under 10 years of age) often present with unexplained emotional lability and daytime or nighttime wetting (enuresis), and the delay in diagnosis may be secondary to families and providers not realizing that Graves disease may be diagnosed in children as young as 2-3 years of age. Teenagers often present with "late onset" ADHD, with a history of good school performance for years and then a sudden drop in grades, with or without symptoms of anxiety. There are multiple reasons why teens may have a decrease in grades, but one needs to consider Graves disease as a possibility.

When the child or teen is brought in for an evaluation, the physician should look for a couple of indicators of thyroid disease. The vital sign assessment will show an unexplained increased heart rate (tachycardia) and potentially unexpected weight loss. About 30% of children will have proptosis—the prominent eyes associated with Graves disease. The eye manifestation is usually more mild and not associated with an increased risk for decreased vision.

Next, have the child or teen look up, and see whether you can see their thyroid gland; it is a butterfly or H-shaped gland that is in the lower one third of the neck, just above the collar bones. Then, determine whether they have a tremor by holding their arms out in a stretched position to see if their hands shake.

If the child or teen has any of those symptoms or signs, then the provider should order a TSH measurement. TSH is a very simple screen and should be completed before a patient is referred for formal ADHD or anxiety testing— or even worse, starting them on a medication.

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