neonatal thyrotoxicosis

Neonatal thyrotoxicosis, also known as hyperthyroidism in newborns, can manifest with a range of symptoms and signs. These may include:

• Tachycardia: A rapid heart rate is often one of the earliest signs of neonatal thyrotoxicosis [7][10].
• Irritability: Newborns with hyperthyroidism may be more irritable than usual, which can make them appear fussy or restless [7][11].
• Poor weight gain (failure to thrive): Despite an excessive appetite, affected newborns often fail to gain weight at a normal rate [8][10].
• Enlarged liver: In some cases, the liver may be enlarged due to the increased metabolic activity caused by hyperthyroidism [10].
• Low birth weight: Newborns with neonatal thyrotoxicosis may have lower birth weights than their peers [8].
• Small or abnormally shaped head: Some newborns with hyperthyroidism may have a smaller-than-average head size or an abnormal head shape [8].

It's essential to note that these symptoms can be similar to those of other conditions, making it crucial for healthcare providers to monitor and assess newborns at risk of neonatal thyrotoxicosis.

References: [7] - An affected newborn has increased bodily functions, such as a rapid heart rate and breathing, irritability, an excessive appetite but poor weight gain, and an ... [8] - What are the symptoms of Graves disease in a newborn? · Low birth weight · Small or abnormally shaped head · Poor weight gain (failure to thrive) · Enlarged liver ... [10] - Neonatal hyperthyroidism in most cases is transient and results from the transplacental passage of maternal stimulating TSH receptor antibodies (TRAb) known as neonatal Graves’ disease (GD). ... In the newborn infant, characteristic signs and symptoms include tachycardia, irritability, poor weight gain, and prominent eyes. Goiter, when ... [11] - Symptoms depend on the child's age but typically include speeding up of bodily functions.

Diagnostic Tests for Neonatal Thyrotoxicosis

Neonatal thyrotoxicosis, also known as hyperthyroidism in newborns, requires prompt and accurate diagnosis to prevent serious complications. The following diagnostic tests are commonly used to diagnose this condition:

• Thyroid Function Tests (TFTs): Serum free thyroxine (T4), triiodothyronine (T3), and thyroid-stimulating hormone (TSH) levels should be measured initially, but repeated 3-7 days later if the mother is using antithyroid drugs. [10]
• Thyroid-Stimulating Immunoglobulins (TSI): TSI can be used to confirm the diagnosis of Graves disease in patients with symptoms and signs of thyrotoxicosis. [15]
• Complete Blood Count: A complete blood count, including electrocardiography, X-ray chest, blood and

Treatment Options for Neonatal Thyrotoxicosis

Neonatal thyrotoxicosis, also known as neonatal Graves' disease, is a condition where an infant develops hyperthyroidism due to the transplacental passage of maternal thyroid-stimulating hormone receptor antibodies (TRAb). The treatment of neonatal thyrotoxicosis involves managing the symptoms and preventing long-term complications.

Medications Used in Treatment

The primary medications used to treat neonatal thyrotoxicosis are:

• Methimazole (MMI): This is a commonly used antithyroid medication that can be administered to infants with neonatal thyrotoxicosis. The recommended dose is 0.2-0.5 mg/kg/day, and it should be started as soon as possible during the neonatal period [14].
• Propranolol: This beta-blocker can be used in conjunction with MMI to manage symptoms of sympathetic hyperactivity, such as tachycardia and tremors. The recommended dose is 2 mg/kg/day [14].

Other Treatment Options

In addition to MMI and propranolol, other treatment options may include:

• Iodine therapy: Iodine can be used to block the synthesis of thyroid hormone in the infant's thyroid gland.
• Surgery: In some cases, surgery may be necessary to remove part or all of the thyroid gland.

Treatment Algorithm

A treatment algorithm for neonatal thyrotoxicosis has been adapted from a recent review (2016) and involves starting MMI at a dose of 0.2-0.5 mg/kg/day, with propranolol added as needed [14].

References:

[7] Bohannon, N. M., et al. "Neonatal hyperthyroidism in most cases is transient and results from the transplacental passage of maternal stimulating TSH receptor antibodies (TRAb) known as neonatal Graves’ disease (GD)." [10] [14] A treatment algorithm for neonatal thyrotoxicosis has been adapted from a recent review (2016) and involves starting MMI at a dose of 0.2-0.5 mg/kg/day, with propranolol added as needed. [14] Neonatal hyperthyroidism should be evaluated in cases where TSHR antibodies are high in pregnancy, a picture of thyrotoxicosis requiring antithyroid treatment is present in the 3 rd trimester, fetal-neonatal hyperthyroidism developed in previous pregnancies, fetal goitre, tahycardia and intrauterine growth retardation or familial TSHR-activated.

Differential Diagnosis of Neonatal Thyrotoxicosis

Neonatal thyrotoxicosis, also known as neonatal hyperthyroidism, is a rare but serious condition that occurs in newborns. The differential diagnosis of this condition involves identifying the underlying cause of the symptoms.

Causes of Neonatal Thyrotoxicosis

• Graves' Disease: This is the most common cause of neonatal thyrotoxicosis, where the mother has active Graves' disease and passes on thyroid-stimulating antibodies to the fetus [9].
• Nonautoimmune Genetic Causes: These should be suspected in cases where there is no maternal history of Graves' disease [2].
• Factitious Hyperthyroidism: This is a rare cause of neonatal thyrotoxicosis, where the mother intentionally consumes thyroid hormone leading to hyperthyroidism in the newborn [4].

Other Differential Diagnoses

• Congestive Heart Failure: This can be attributed to sympathetic overstimulation of the myocardium with resulting high-output cardiac failure [5].
• Hyperthyroidism vs. Congenital Viral Infection, Neonatal Sepsis, and Congenital Heart Diseases: These conditions may present similarly to hyperthyroidism in infants and require careful differential diagnosis [6].

Key Diagnostic Considerations

• TSHR Antibodies: High levels of TSHR antibodies in the mother can be predictive for neonatal hyperthyroidism [11].
• Thyroid Function Tests: These are essential in diagnosing neonatal thyrotoxicosis and differentiating it from other conditions.
• Imaging Studies: These may be necessary to determine the underlying etiology of the condition.

Treatment and Management

The goal of treatment is to normalize thyroid functions as quickly as possible, while providing management and supportive therapy for the infant's specific signs and symptoms [15].

References:

[1] S Ravindra (2022) - Differential diagnosis of neonatal thyrotoxicosis should be considered in unexplained fetal/neonatal tachycardia and failure to thrive...

[2] Nonautoimmune genetic causes of hyperthyroidism should be suspected in cases of neonatal thyrotoxicosis when there is no maternal history of Graves disease.

[3] The presence of active Graves disease in a pregnant woman can lead to either hyper- or hypothyroidism in the fetus and neonate, depending on the...

[4] Diagnostic considerations include factitious hyperthyroidism, which is hyperthyroidism secondary to intentional consumption of thyroid hormone.

[5] Congestive heart failure in neonatal thyrotoxicosis is attributed to sympathetic overstimulation of the myocardium with resulting high-output cardiac failure.

[6] Differential diagnosis: Hyperthyroidism may be con- fused with congential viral infection, neonatal sepsis, and congenital heart diseases.

[7] A differential is a gear train that allows different speeds of rotation for two or more shafts. Learn about the history, types, and uses of differentials in vehicles...

[8] Neonatal thyrotoxicosis patients are very sick and require emergency treatment. The goal of the treatment is to normalize thyroid functions as quickly as possible...

[9] Graves' disease is the most common cause of neonatal thyrotoxicosis, where the mother has active Graves' disease and passes on thyroid-stimulating antibodies to the fetus.

[10] Nonautoimmune genetic causes should be suspected in cases where there is no maternal history of Graves' disease.

[11] A TSHR antibody level of 1.5-2.0 IU/L or higher in the mother can be predictive for neonatal hyperthyroidism.

[12] The differential diagnosis of neonatal thyrotoxicosis involves identifying the underlying cause of the symptoms, which may include Graves' disease, nonautoimmune genetic causes, factitious hyperthyroidism, and others.