Management of foetal hyperthyroidism in a mother with autoimmune hypothyroidism: A case report

Foetal hyperthyroidism is mediated by transplacental passage of thyroid stimulating antibodies (TSAbs) and affects mothers with autoimmune (AI) thyroid disease. We report a case of a 33-year-old woman with a history of AI hypothyroidism and raised TSI after 2 stillbirths with suspect foetal hyperthyroidism. At 20.5 gestational weeks (GW) of her third pregnancy, foetal tachycardia and goitre were detected. TSI levels were 30.9mUI/mL. Methimazole (MMI) was started and adjusted based on ultrasound signs (foetal heart rate and thyroid gland vascularisation). The neonate was born at 35GW and cord blood revealed decreased TSH and normal free T4. MMI was started in the neonate at 2 days of life due to the appearance of asymptomatic hyperthyroidism. This case illustrates a rare recurrence of foetal hyperthyroidism in a mother with AI hypothyroidism. Pregestational thyroidectomy, TSAbs determination, early ultrasound diagnosis and foetal therapy helped us to improve obstetric outcomes.

Update on Pediatric Hyperthyroidism

Typical symptoms which should lead to suspicion of hyperthyroidism are unintentional weight loss, tachycardia, and palpitations, heat intolerance, and hyperactivity. It is diagnosed by suppressed thyroid-stimulating hormone (TSH) with elevated thyroid hormone (TH) levels. Graves' disease (GD) due to antibodies stimulating the TSH receptor is the leading cause, and first-line treatment is with methimazole (MMI). Emerging data suggest MMI treatment, up to 8 years is effective and safe in improving the rate of remission. Radioactive iodine (RAI) and thyroidectomy offer definitive treatment and induce permanent hypothyroidism. Thyroid storm is a life-threatening condition with systemic decompensation and hyperpyrexia. Neonates of mothers with current or past GD are at risk for neonatal hyperthyroidism (NH). Appropriate identification and follow-up of at-risk neonates will reduce complications.

A hypothyroid mother after subtotal thyroidectomy delivered a newborn with hyperthyroidism from fetal stage: a case report

BACKGROUND

Neonatal hyperthyroidism is an extension of fetal disease. Most cases of neonatal hyperthyroidism are transient but may excessively harm multiple organ functions through the actions of maternal thyroid-stimulating hormone receptor antibodies on the neonatal thyroid gland.

CASE PRESENTATION

The hyperthyroid mother underwent subtotal thyroidectomy before pregnancy and regularly took levothyroxine to avoid hypothyroidism, but still had a high-level thyroid-stimulating hormone receptor antibody (TRAb). The neonate suffered from hyperthyroidism due to the transplacental TRAb. After a regular medication schedule of an antithyroid drug, combined with a β-blocker to control the ventricular rate, the infant gradually recovered, allowing normal motor and intellectual development.

CONCLUSIONS

Maternal subtotal thyroidectomy cannot prevent the secretion of thyroid receptor antibodies, which may cause either hypothyroidism or hyperthyroidism. The balance between antithyroid drugs and levothyroxine is critical in clinical practice.

TSHRV656F Activating Variant of the Thyroid Stimulating Hormone Receptor Gene in Neonatal Onset Hyperthyroidism: A Case Review

An activating variant of the thyroid stimulating hormone receptor (TSHR) gene is one of the rare causes of neonatal hyperthyroidism. This disorder may occur as a result of an autosomal dominant inheritance or sporadically through de novo variation. Here we present a case of neonatal onset congenital non-autoimmune hyperthyroidism (NAH) with a sporadic germline activating TSHRV656F variant. A female infant with tachycardia, who was transferred due to hyperthyroidism in the first week of life, displayed no other symptoms or signs. The patient’s mother did not have Graves’ disease, and TSHR stimulating antibodies were not present in the mother or baby. Imaging showed thyroid gland hyperplasia and left ventricular hypertrophy, the patient was subsequently put on methimazole treatment. After six months undergoing treatment, a heterozygous p.Val656Phe (V656F) (c.1966G>T) variant was detected on exon 10 of the TSHR gene. The variant was not identified in the mother and father, so the case was assumed to be sporadic. In conclusion, although the literature describes V656F variant as a somatic variant in children and adults with toxic thyroid nodule(s) that results in the structural activation of the TSH receptor, no previous cases of neonatal hyperthyroidism due to TSHRV656F variant have been reported. This study is the first case review that highlights the relationship between TSHRV656F variant and neonatal onset NAH.

Hemodynamic changes in neonates born to mothers with Graves' disease

PURPOSE

Cardiac insufficiency is a major morbidity in neonatal hyperthyroidism. It is important to assess the hemodynamics in neonates born to mothers with Graves' disease (GD). This study prospectively evaluated the hemodynamic changes in neonates born to mothers with GD.

METHODS

Overall, 80 newborns were enrolled. Thirty-six neonates were born to mothers with GD who were positive for thyroid-stimulating hormone (TSH) receptor antibody (TRAb), and 44 were born to mother negative for TRAb. The serum levels of TSH, free triiodothyronine (FT₃), free thyroxine (FT₄), and N-terminal-pro-B-type natriuretic peptide (NT-proBNP), the cardiac output, and cardiac index (CI) evaluated by echocardiography were compared between the two groups at several postnatal points (day of delivery and 5, 10, and 30 days of life).

RESULTS

The TRAb-positive newborns had higher FT₄ levels and CI on Day 5 (both p < 0.05) and higher FT₃ (p < 0.05) and FT₄ levels (p < 0.01) and CI (p < 0.01) but lower TSH levels (p < 0.05) on Day 10 than the TRAb-negative newborns. The TRAb-positive newborns had significantly higher NT-proBNP levels on Days 5 (median 752 vs. 563 pg/mL, p = 0.034) and 10 (median 789 vs. 552 pg/mL, p = 0.002) than the TRAb-negative newborns.

CONCLUSIONS

Hemodynamic changes in neonates born to TRAb-positive mothers with GD resulted in a higher CI and NT-proBNP levels than in those with TRAb-negative mothers from postnatal days 5 to 10.

Neonatal Thyroid Disease: Testing and Management

"Thyroid dysfunction that requires prompt diagnosis and treatment often becomes evident in the newborn period because of testing that is done as part of universal newborn screening. Primary congenital hypothyroidism is the most common treatable cause of mental retardation, requiring immediate treatment to prevent abnormal brain development. However, many of the abnormal thyroid test results are less abnormal and difficult to interpret, with a need for repeat testing and careful follow-up before initiation of treatment. Less often, neonatal hyperthyroidism is encountered. This article reviews and discusses management of thyroid dysfunction that may present in the first month after birth."

Graves' hyperthyroidism in pregnancy: a clinical review

Background

Graves’ hyperthyroidism affects 0.2% of pregnant women. Establishing the correct diagnosis and effectively managing Graves’ hyperthyroidism in pregnancy remains a challenge for physicians.

Main

The goal of this paper is to review the diagnosis and management of Graves’ hyperthyroidism in pregnancy. The paper will discuss preconception counseling, etiologies of hyperthyroidism, thyroid function testing, pregnancy-related complications, maternal management, including thyroid storm, anti-thyroid drugs and the complications for mother and fetus, fetal and neonatal thyroid function, neonatal management, and maternal post-partum management.

Conclusion

Establishing the diagnosis of Graves’ hyperthyroidism early, maintaining euthyroidism, and achieving a serum total T4 in the upper limit of normal throughout pregnancy is key to reducing the risk of maternal, fetal, and newborn complications. The key to a successful pregnancy begins with preconception counseling.

Biochemical Hyperthyroidism in a Newborn Baby Caused by Assay Interaction from Biotin Intake

We describe a case of biochemical neonatal thyrotoxicosis caused by biotin supplementation. Biotin may interact with thyroid function testing to imitate thyrotoxicosis with low thyroid-stimulating hormone and elevated triiodothyronine and thyroxine levels.