Outcomes of children with hashitoxicosis

AIM: To investigate hashitoxicosis outcome in 14 children with persistent absence of thyrotropin receptor autoantibodies who were followed for 1.3-8.8 years (mean 3.5 ± 2.5). Due to a more severe presentation, 4 patients required methimazole (subgroup A1), whilst in the remaining 10 cases (subgroup A2) no treatment was given. RESULTS: A definitive resolution of hyperthyroidism was recorded 8.3 ± 6.3 months after diagnosis, even though there was a wide variability between subjects (3-23 months). In subgroup A2, hyperthyroidism resolution occurred spontaneously and earlier with respect to subgroup A1 (4.8 ± 2.0 months after diagnosis vs. 17.0 ± 4.5, p = 0.00001). After hyperthyroidism resolution, no relapses were recorded in any patients. Hyperthyroidism duration positively correlated with thyroid peroxidase autoantibody (TPOAb) levels at presentation (r = 0.729, p = 0.002). CONCLUSIONS: In all the 14 hashitoxicosis children with persistently absent thyrotropin receptor autoantibodies, the hyperthyroid phase was widely variable and always followed by definitive resolution with no relapses and persistent euthyroidism or hypothyroidism. In the few patients with a more severe presentation, methimazole treatment was required, and definitive hyperthyroidism resolution was delayed. In this subgroup, TPOAb levels at diagnosis were higher than in the subgroup with less severe presentation and earlier hyperthyroidism resolution, suggesting a relationship between TPOAb levels and severity of the disease.