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Subclinical hyperthyroidism when presenting as initial manifestation of juvenile Hashimoto's thyroiditis: first
Insights
Pediatric subclinical hyperthyroidism (SH) due to Hashimoto's thyroiditis (HT) often resolves within 24 months. Some children may develop hypothyroidism or Graves' disease, suggesting SH and overt hyperthyroidism (Htx) may be stages of the same condition.
Area of Science:
- Pediatric Endocrinology
- Thyroidology
- Autoimmune Diseases
Background:
- Limited data exist on the natural history of endogenous subclinical hyperthyroidism (SH) in children.
- Hashimoto's thyroiditis (HT) is a common cause of thyroid dysfunction in pediatric populations.
Purpose of the Study:
- To investigate the natural history of SH as an initial manifestation of HT in children.
- To compare the spontaneous evolution of HT-related SH with HT-related frank hyperthyroidism (Hashitoxicosis, Htx) in age-matched pediatric patients.
Main Methods:
- Retrospective analysis of two groups of children with HT.
- Group A: presented with SH (suppressed TSH, normal FT4).
- Group B: presented with Htx (suppressed TSH, elevated FT4).
- Follow-up assessment of thyroid function and antibody levels.
Main Results:
- TSH normalization occurred spontaneously within 1-24 months in the SH group and 3-9 months in the Htx group.
- In the SH group, the time to normalization correlated with baseline thyroid peroxidase antibodies.
- During follow-up, most patients remained euthyroid, but some developed hypothyroidism or Graves' disease.
Conclusions:
- Hashimoto's thyroiditis should be recognized as a cause of endogenous SH in children.
- Spontaneous TSH normalization in pediatric HT-related SH occurs within 24 months, similar to Htx.
- Deterioration of thyroid function can occur during follow-up in both conditions, suggesting they may represent stages of a continuum.
Background:
Due to the lack of specific pediatric studies, no data are available about natural history of endogenous subclinical hyperthyroidism (SH) in childhood.
Aims:
(a) To investigate for the first time the natural history of SH [suppressed thyrotropin (TSH) and normal free thyroxine free thyroxine (FT4) levels] when presenting as initial manifestation of Hashimoto's thyroiditis (HT) in childhood (group A); (b) to compare spontaneous evolution of HT-related SH with that observed in age-matched patients with HT-related frank hyperthyroidism (suppressed TSH and elevated FT4 levels), i.e., Hashitoxicosis Htx (group B).
Results:
In the 11 patients of group A, TSH normalization spontaneously occurred 1-24 months after diagnosis, while in the 10 patients of group B it occurred 3-9 months after diagnosis, with no differences between the 2 groups in terms of time interval from entry to TSH normalization. In group A, this time interval was related to baseline thyroid peroxidase antibodies (r=0.78, p = 0.04). During follow-up, eight patients of each group remained euthyroid, whereas two became hypothyroid (in both groups) and one developed Graves' disease (in group A).
Conclusion:
(a) HT should be included among the causes of endogenous SH in pediatric age; (b) in children with HT-related SH, spontaneous normalization of TSH levels occurs within the first 24 months after diagnosis, as well as in age-matched patients with Htx; (c) in both these conditions, a further deterioration of thyroid function might re-present in some patients during follow-up; (d) Ht-related SH and Htx might be possibly seen as different biochemical stages along the same continuum.
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