The presence of positive anti-thyroid antibodies may suggest more severe hypothyroidism in children who present with anti-thyroid peroxidase and/or anti-thyroglobulin antibodies, say researchers who presented at ENDO 2021 last month.
The study, presented by Rasha Alradadi, MBBS, of Saudi Arabia, sought to explain the common characteristics of pediatric patients with antibody negative primary hypothyroidism in a retrospective chart review of pediatric patients with hypothyroidism. The patients were treated at the pediatric endocrine clinic at Riley Hospital for Children in Indianapolis, Indiana between August 2016 and December 2019.
After a review of age at diagnosis, signs and symptoms at presentation, height, weight, BMI, TSH, FT4, T4, thyroid peroxidase and anti-thyroglobulin antibodies, family history of thyroid disease, physical exam at diagnosis, and associated diseases, Alradadi et al. concluded that a hypothryroid diagnosis with positive antibodies usually lead to a more severe case of hypothyroidism.
“Patients with positive anti-thyroid antibodies had more severe hypothyroidism and were more likely to report extreme fatigue than those with negative antibodies. It is unknown why some children with acquired primary hypothyroidism presumed due to autoimmune thyroid disease have negative antibodies,” the authors wrote.
The study included 173 patients between 3.9 years old and 10.6 years. Of these, 128 (74% of 173) patients (80% female) had positive antibodies and 44 (26%) patients (53% female) had negative antibodies.
Of patients with positive antibodies, having a family history of thyroid disease was a factor in 45% of cases with positive antibodies and in 22% of patients with negative antibodies (P=0.006). In terms of fatigue, which affects most patients with hypothyroidism, 45% of patients with positive antibodies reported excessive fatigue and 31% of these patients had a goiter.
Fatigue was less of a factor for patients with negative antibodies as only 22.7% reported having mild intermittent fatigue (P=0.006) and 15.9% of these patients had a goiter (P=0.04).
Patients with positive antibodies also had extremely high TSH levels. A TSH higher than 4.0 mU/L usually suggests a hypothyroid. In this group, patients had TSH levels of 129± 230 mcu/ml. Patients with negative antibodies had TSH levels of 48 ± 131 mcu/ml (P=0.04).
Similar patterns were found with FT4 which, in healthy subjects, are generally 0.7-1.9 ng.dL. But the levels were low for hypothyroid patients with positive antibodies (0.68±0.37 vs 0.85±0.27, P=0.050).
The presence or absence of antibodies did not have an effect on the incidence of obesity or Down syndrome in hypothyroid patients.
“Long-term follow-up will be needed to determine whether the natural history of thyroid disease in children with primary hypothyroidism is associated with antibody status,” the authors wrote.
Rasha Alradadi, MBBS, Erica A. Eugster, MD. “What Are the Common Characteristics of Pediatric Patients With Antibody Negative Primary Hypothyroidism?” ENDO Society 2021. P52-10. March 20, 2021