Diagnosis and Management of Fetal and Neonatal Thyrotoxicosis

Neonatal Thyrotoxicosis in Infants of Mothers with Graves' Disease Treated for Radioiodine-Induced Hypothyroidism: A Literature Review

Fetal and neonatal thyrotoxicosis occurs in up to 5% of pregnancies in mothers with Graves' disease (GD). This condition is caused by stimulating antibodies against the thyrotropin receptor (TRAbs) that cross the placenta and may stimulate the fetal thyroid, typically in the second half of pregnancy. GD is often treated with radioiodine, resulting in hypothyroidism in most patients, but TRAbs can persist for several years. Even if a pregnant mother is hypothyroid after radioiodine therapy or surgery, her TRAbs can still, although rarely, induce fetal hyperthyroidism. In this review, we first present two cases of neonatal hyperthyroidism in mothers with GD who became hypothyroid after prior radioiodine therapy, identified through a 10-year analysis of the National Perinatal System in Slovenia. Based on these cases, we provide an overview of existing data on this rare clinical condition in neonates. We also discuss the underlying mechanisms and clinical outcomes based on currently available data. In conclusion, our review highlights the importance of careful monitoring during pregnancy in all women with GD, even in those well managed after radioiodine therapy or surgery.

Thyroid stimulating receptor autoantibodies

Thyroid-stimulating hormone receptor autoantibodies (TRAbs) play a crucial role as pathogenic antibodies in both the diagnosis and management of Graves' disease (GD). GD, an autoimmune disease resulting from a combination of genetic and environmental factors, is the most common cause of hyperthyroidism. With advancements in technology for TRAb detection and the availability of automated commercial kits, TRAb has become an essential clinical laboratory marker for the diagnosis of GD, as well as extra-thyroidal manifestations like Graves' ophthalmopathy (GO). This article provides a comprehensive review of TRAb, encompassing its clinical assays along with its significance in the clinical setting.

Diagnosis and Management of Fetal Arrhythmias in the Current Era

Diagnosis and management of fetal arrhythmias have changed over the past 40-50 years since propranolol was first used to treat fetal tachycardia in 1975 and when first attempts were made at in utero pacing for complete heart block in 1986. Ongoing clinical trials, including the FAST therapy trial for fetal tachycardia and the STOP-BLOQ trial for anti-Ro-mediated fetal heart block, are working to improve diagnosis and management of fetal arrhythmias for both mother and fetus. We are also learning more about how "silent arrhythmias", like long QT syndrome and other inherited channelopathies, may be identified by recognizing "subtle" abnormalities in fetal heart rate, and while echocardiography yet remains the primary tool for diagnosing fetal arrhythmias, research efforts continue to advance the clinical envelope for fetal electrocardiography and fetal magnetocardiography. Pharmacologic management of fetal arrhythmias remains one of the most successful achievements of fetal intervention. Patience, vigilance, and multidisciplinary collaboration are key to successful diagnosis and treatment.

The tortuous diagnosis of one case of neonatal hyperthyroidism

OBJECTIVE

To outline the clinical signs, diagnosis, and course of care for a single case of neonatal hyperthyroidism while also summarizing common diagnostic errors related to this condition.

METHODS

Medical records of the neonate of hyperthyroidism were collected and analyzed in combination with literature.

RESULTS

The neonate's mother had thyroid disease, but her thyrotropin receptor antibody (TRAb) levels were not monitored during pregnancy. The neonate exhibited typical symptoms of hyperthyroidism on the day of birth but was not diagnosed until 15 days later. Impaired liver (cholestasis, elevated liver enzymes) and cardiac function (pulmonary hypertension, right heart enlargement) are the main manifestations. Treatment with methimazole (1.0 mg /kg·d) and propranolol (2.0 mg /kg·d) led to recovery, and the neonate stayed in the hospital for 27 days before being discharged with medication. The diagnosis was temporary hyperthyroidism, and the medication was discontinued at 72 days of age.

CONCLUSION

It is important to strengthen the management of high-risk pregnant women with thyroid disease. Monitoring TRAb levels in both mothers and neonates should be done dynamically to enable early prediction and diagnosis of neonatal hyperthyroidism. Most neonates with hyperthyroidism have a good prognosis when timely and appropriate medical treatment is provided.