Thyroid stimulating immunoglobulin is often negative in children with Graves' disease

Approach to the Patient: Management and the Long-term Consequences of Graves' Disease in Children

In children, Graves' disease (GD) is the most common cause of hyperthyroidism. Most pediatric patients with GD will not go into lasting remission, even following many years of antidrug therapy. Thus, most pediatric patients will require radioactive iodine (RAI) or surgery. When antithyroid drugs are used, methimazole is the drug of choice. When methimazole is used in children, up to 20% will have minor adverse reactions and serious adverse events occur in up to 1%. RAI is an effective form of therapy when the thyroid size is less than 80 g. Because of concerns of whole-body radiation exposure, it is recommended that RAI be avoided in children under 5 years of age, and dosages less than 10 mCi be used between 5 and 10 years of age. Surgery is an effective treatment in children if performed by a high-volume thyroid surgeon. Because of the scarcity of high-volume pediatric thyroid surgeons, a multidisciplinary approach using pediatric surgeons and endocrine surgeons can be considered. Whereas there is a trend toward long-term antithyroid drug therapy in adults, for several reasons, this approach may not be practical for children. Determining the optimal treatment for the pediatric patient with GD, requires consideration of the risks and benefits relating to age and likelihood of remission.

Differential Diagnosis of Thyrotoxicosis by Machine Learning Models with Laboratory Findings

Differential diagnosis of thyrotoxicosis is essential because therapeutic approaches differ based on disease etiology. We aimed to perform differential diagnosis of thyrotoxicosis using machine learning algorithms with initial laboratory findings. This is a retrospective study through medical records. Patients who visited a single hospital for thyrotoxicosis from June 2016 to December 2021 were enrolled. In total, 230 subjects were analyzed: 124 (52.6%) patients had Graves’ disease, 65 (28.3%) suffered from painless thyroiditis, and 41 (17.8%) were diagnosed with subacute thyroiditis. In consideration that results for the thyroid autoantibody test cannot be immediately confirmed, two different models were devised: Model 1 included triiodothyronine (T3), free thyroxine (FT4), T3 to FT4 ratio, erythrocyte sediment rate, and C-reactive protein (CRP); and Model 2 included all Model 1 variables as well as thyroid autoantibody test results, including thyrotropin binding inhibitory immunoglobulin (TBII), thyroid-stimulating immunoglobulin, anti-thyroid peroxidase antibody, and anti-thyroglobulin antibody (TgAb). Differential diagnosis accuracy was calculated using seven machine learning algorithms. In the initial blood test, Graves’ disease was characterized by increased thyroid hormone levels and subacute thyroiditis showing elevated inflammatory markers. The diagnostic accuracy of Model 1 was 65–70%, and Model 2 accuracy was 78–90%. The random forest model had the highest classification accuracy. The significant variables were CRP and T3 in Model 1 and TBII, CRP, and TgAb in Model 2. We suggest monitoring the initial T3 and CRP levels with subsequent confirmation of TBII and TgAb in the differential diagnosis of thyrotoxicosis.

Prognostic factors of restrictive myopathy in thyroid eye disease

To investigate the prognostic factors of extraocular muscle restriction in patients with thyroid eye disease (TED), 65 patients with TED and restrictive myopathy were evaluated. Demographics, clinical activity score (CAS), smoking status, thyroid disease status, thyroid hormone status, thyroid autoantibody status, orbital computed tomography (CT) scan at initial presentation, and treatment regimens were assessed. The movements of the most severely affected extraocular muscles were categorized into five grades. The patients were divided into the improved and the not-improved group based on the improvement in the limitation of the extraocular muscle excursion (LOM) throughout the follow-up, and the groups were compared using clinical factors. The mean LOM significantly improved from 2.3 ± 1.1 to 1.7 ± 1.2 after 1 year of follow-up. The excursion of the most restricted muscle improved in 32 patients but not in 33 patients during the follow-up. The initial concentration of the thyroid-stimulating antibody (TSAb) was significantly lower in the improved (229.3 ± 114.1) than in the not-improved group (345.0 ± 178.6) (P = 0.02) Age, sex, smoking status, CAS, thyroid status, and muscle thickness on the CT scan did not significantly differ in the groups. This study showed that the initial concentration of TSAb is a factor affecting the recovery of restrictive myopathy.

Thyroid Stimulating Hormone Receptor Antibodies in Thyroid Eye Disease-Methodology and Clinical Applications

BACKGROUND

Thyroid stimulating hormone receptor antibodies (TSHR-Ab) cause autoimmune hyperthyroidism and are prevalent in patients with related thyroid eye disease (TED).

PURPOSE

To provide a historical perspective on TSHR-Ab and to present evidence-based recommendations for clinical contemporary use.

METHODS

The authors review the recent literature pertaining to TSHR-Ab in patients with TED and describe the various immunoassays currently used for detecting TSHR-Ab and their clinical applications.

RESULTS

We provide a historical summary and description of the various methods used to detect TSHR-Ab, foremost, the functional TSHR-Ab. Increasing experimental and clinical data demonstrate the clinical usefulness of cell-based bioassays for measurements of functional TSHR-Ab in the diagnosis and management of patients with autoimmune TED and in the characterization of patients with autoimmune-induced hyperthyroidism and hypothyroidism. Thyroid stimulating hormone receptor antibodies, especially the functional stimulating antibodies, are sensitive, specific, and reproducible biomarkers for patients with autoimmune TED and correlate well with clinical disease activity and clinical severity. Unlike competitive-binding assays, bioassays have the advantage of indicating not only the presence of antibodies but also their functional activity and potency.

CONCLUSIONS

Measurement of TSHR-Ab (especially stimulating antibodies) is a clinically useful tool for the management of patients with TED.

Thyroidectomy in a two-year old for graves' disease

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The most common cause of hyperthyroidism in children is graves’ disease.

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Surgery is utilized as a therapy for graves’ disease but rarely employed in children.

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This case report represents the youngest patient to undergo thyroidectomy for graves’ disease.

Introduction

The most common cause of hyperthyroidism in children is graves’ disease – an autoimmune disorder in which antibodies stimulate the thyrotropin receptor to signal growth thyroid gland by increasing thyroid hormone synthesis and release. It can be treated with medical therapy, radioactive iodine, or surgery.

Presentation of case

JD was a two year old male who presented with severe diarrhea and diffuse neck enlargement. Laboratory work up was consistent with graves’ disease.

Discussion

Despite maximal outpatient and inpatient treatment with methimazole, atenolol, prednisone, and SSKI, he suffered persistent thyrotoxicosis. He underwent near-total thyroidectomy without complication.

Conclusion

This case is notable as it may represent the youngest patient in the literature who has undergone thyroidectomy for graves’ disease.

Diagnosis of pediatric hyperthyroidism: technetium 99 uptake versus thyroid stimulating immunoglobulins

BACKGROUND

Treatment with antithyroid drugs is effective in conditions of increased thyroid hormone production (mostly Graves' Disease; GD), but not in subacute thyroiditis (SAT) or autoimmune thyroiditis (AIT). Positive thyroid stimulating immunoglobulins (TSI) make GD likely. However, not all children with GD have increased TSI. Uptake studies with (123)I or (99)Tc ((99m)Tc) provide accurate and rapid diagnosis but are expensive and involve radiation exposure. Our objective was to compare TSI with (99m)Tc uptake for diagnosis of pediatric hyperthyroidism.

METHODS

We performed a retrospective chart review of hyperthyroid children who had both TSI estimation and (99m)Tc uptake assessment at presentation. Based on subsequent laboratory studies and follow-up, 37 had GD and 10 had non-GD thyroiditis. The TSI index was considered positive (TSI+) when it was above the upper limit of normal. (99m)Tc uptake was considered positive (Tc+) for any uptake >0.4% and negative (and low) (Tc-) for uptake ≤0.4%.

RESULTS

Forty-seven youth (83% females), aged 12.3±4.6 years, presented with a suppressed thyrotropin (TSH) and elevated free thyroxine and total triiodothyronine. All 37 patients with GD were Tc+ (100% sensitivity and specificity). The sensitivity of TSI for diagnosing GD was 84%, and the specificity was 100%. Six patients with GD were discordant with Tc+ but TSI-. Elevated TSI correlated with Tc+ (p=0.01) with a degree of agreement (kappa) of 0.69.

CONCLUSION

(99m)Tc has excellent specificity and sensitivity in diagnosing GD. Given additional costs of (99m)Tc (two and a half times as much as TSI), it is reasonable to reserve (99m)Tc uptake assessment for hyperthyroidism of unclear etiology and negative TSI.

Long-Term Follow-Up of a Child with Autoimmune Thyroiditis and Recurrent Hyperthyroidism in the Absence of TSH Receptor Antibodies

Hashitoxicosis is an initial, transient, hyperthyroid phase that rarely affects patients with Hashimoto thyroiditis. We present here an unusual case of a child with Hashimoto thyroiditis and recurrent hyperthyroidism. A 4 yr 6/12 old male was diagnosed by us with autoimmune subclinical hypothyroidism (normal free T4, slightly elevated TSH, and elevated TG antibody titer). Two years and 6/12 later he experienced increased appetite and poor weight gain; a laboratory evaluation revealed suppressed TSH, elevated free T4, and normal TSI titer. In addition, an I¹²³ thyroid uptake was borderline-low. A month later, the free T4 had normalized. After remaining asymptomatic for 3 years, the patient presented again with increased appetite, and he was found with low TSH and high free T4. Within the following 3 months, his free T4 and TSH normalized. At his most recent evaluation, his TSH was normal and the free T4 was borderline-high; the TG antibody titer was still elevated and the TSI titer was negative. To our knowledge, this is the first patient reported with Hashimoto thyroiditis and recurrent hyperthyroidism. This case exemplifies the variability of the manifestations and natural history of Hashimoto thyroiditis and supports the need for a long-term evaluation of patients with autoimmune thyroid disease.

Clinical relevance of thyroid-stimulating autoantibodies in pediatric graves' disease-a multicenter study

CONTEXT AND OBJECTIVE

The incidence of TSH receptor (TSHR) stimulating autoantibodies (TSAbs) in pediatric Graves' disease (GD) is controversial. This large, multicenter study evaluated the clinical relevance of TSAbs in children with GD both with Graves' orbitopathy (GO) and without orbital disease.

DESIGN

We conducted a cross-sectional retrospective study.

SETTING

Sera were collected in seven American and European academic referral centers and evaluated in a central laboratory. PATIENTS AND SAMPLES: A total of 422 serum samples from 157 children with GD, 101 control individuals with other thyroid and nonthyroid autoimmune diseases, and 50 healthy children were studied.

MAIN OUTCOME MEASURES

TSAbs were measured using a novel, chimeric TSHR bioassay and a cAMP response element-dependent luciferase. TSH binding-inhibitory Ig (TBII) and parameters of thyroid function were also determined.

RESULTS

In 82 untreated children with GD, sensitivity, specificity, and positive and negative predictive values for TSAb and TBII were: 100 and 92.68% (P = .031), 100 and 100%, 100 and 100%, and 100 and 96.15%, respectively. TSAb and TBII were present in 147 (94%) and 138 (87.9%) of the 157 children with GD (P < .039), respectively; and in 247 (94%) and 233 (89%) of the 263 samples from this group (P < .0075), respectively. In children with GD and GO, TSAb and TBII were noted in 100 and 96% (P < .001), respectively. Hyperthyroid children with GD and GO showed markedly higher TSAb levels compared to those with thyroidal GD only (P < .0001). No significant differences were noted for TBII between the two groups. After a 3-year (median) medical treatment, the decrease of TSAb levels was 69% in GD vs 20% in GD and GO (P < .001). All 31 samples of euthyroid children with GO were TSAb positive; in contrast, only 24 were TBII positive (P = .016). All children with Hashimoto's thyroiditis, nonautoimmune hyperthyroidism, type 1 diabetes, and juvenile arthritis and the healthy controls were TSAb and TBII negative.

CONCLUSIONS

Serum TSAb level is a sensitive, specific, and reproducible biomarker for pediatric GD and correlates well with disease severity and extrathyroidal manifestations.