Relationship between infant hypothyroidism and maternal thyroid disease

Background: Due to the very high complications of neonatal hypothyroidism in the country, neonatal screening program is performed for timely diagnosis and treatment of neonates. The aim of this study to investigate the relationship between infant hypothyroidism and maternal thyroid disease. Methods: This cross-sectional study was done on 195 neonates with a diagnosis of hypothyroidism. Necessary data were collected by a checklist and then analyzed by statistical methods in statistical package for the social sciences (SPSS) version 21 by statistical methods. Results: Of all mothers, 21.0% had a history of thyroid disease. There was no statistically significant relationship between maternal age and infant thyroid stimulating hormone (TSH). There was no significant relationship between the history of maternal hypothyroidism and maternal hypothyroidism (during experiments) with the amount of TSH in the newborn. There was a direct and significant relationship between maternal TSH level and maternal free T4. But there was no statistically significant relationship between infant TSH level and maternal TSH level and free T4. There was no significant difference in neonatal TSH levels with maternal anti-TPO status. There was no significant relationship between the history of maternal diabetes and the history of maternal hypertension with neonatal TSH. There was no significant difference in neonatal TSH levels by maternal thyroid status. Conclusions: In the present study, no significant relationship was found between the incidence of neonatal hypothyroidism and the presence of thyroid disease in mothers. The existence of different genetic and environmental factors and the significant impact of each of these factors can justify this result.

Hipotiroidismo neonatal: fisiopatogenia, aspectos moleculares, metabólicos y clínicos / Neonatal hypothyroidism: Pathophysiogenic, molecular and clinical aspects

This review provides an updated summary on both the clinical and diagnostic aspects of neonatal hypothyroidism (NeH); as well as on the molecular and pathophysiologic processes known to be involved in the installment of this important hormonal deficiency. Current information regarding its etiology and pathogenesis has allowed classigying NeH in three major groups: endemic, transient, and sporadic hypothyroidism. The later corresponds to congenital hypothyroidism and encompasses a broad spectrum of hereditary disorders causing hypothyroidism in newborns and young children. These congenital disorders include hypothalamic-pituitary or thyroid dysgenesis and/or dyshormonogenesis, as well as hyporesponsiveness or resistance to either TRH, TSH or to thyroid hormones. The introduction of national screening programs for NeH have overcome the difficulties in the early diagnosis thus helping to prevent its serious and irreversible consequences on intellectual and physical development. Concomitantly, an increase in the need for complementary etiologic and molecular diagnosis has risen. The current capability to perform a fine and precise diagnose is crucial both for treatment of the affected infant and for genetic counseling of the family. Although incomplete, available epidemiological information in Mexico indicates that NeH prevalence can be as high as twice that in other developed world countries. On these bases, national public health policies and epidemiological surveyance must be strengthen not only to identify, diagnose and timely treat, but to prevent and eradicate endemic NeH.

Este trabajo revisa algunos aspectos del conocimiento actual sobre la fisiopatogenia, los hallazgos clínicos y el diagnóstico bioquímico y molecular del hipotiroidismo neonatal (HNe). El término HNe denota un conjunto de entidades clínicamente pleomórficas, que invariablemente cursan con una disminución en el aporte; o bien, en la disponibilidad celular y/o en la respuesta a las hormonas tiroideas (HT) durante la etapa perinatal. Las HT o yodotironinas son indispensables para la morfogénesis y maduración funcional normal de prácticamente todos los tejidos en el organismo, y su participación es crucial en el caso del sistema nervioso. La información actual permite realizar una clasificación del HNe tanto en términos etio y fisiopatogénicos, como en el contexto del substrato genético que los determina. Así, se reconocen tres grandes tipos de HNe: el endémico, el transitorio y el esporádico. Este último grupo de HNe incluye los defectos hipotálamo-hipofisiarios, los trastornos ontogenéticos o disgenesias tiroideas, la resistencia periférica a las HT y las dishormonogénesis. Por otra parte, en la comunidad internacional existe una creciente preocupación por la contaminación ambiental debida a órgano-halógenos antropogénicos. Estos compuestos han mostrado su potencial como agentes distiroideos en animales de experimentación y en algunos estudios clínicos. En México, tanto la distribución geográfica y prevalencia del HNe, como la deficiencia de yodo y otros micronutrimentos en la dieta, se han analizado de manera esporádica y no sistemática. Aunque incompleta, la información disponible sugiere que en nuestro país la prevalencia de HNe es sensiblemente mayor que la reportada mundialmente. Contar con información completa y confiable acerca de estos aspectos no es trivial, puesto que su conocimiento permitirá establecer políticas razonadas de salud pública para identificar, diagnosticar y tratar oportunamente el padecimiento; así como para prevenir y erradicar el HNe endémico.

A Case of Transient Neonatal Hypothyroidism Due to Maternal TSH-Binding Inhibitor Immunoglobulins / 대한소아내분비학회지

Recognition of transient forms of neonatal hypothyroidism is very important to prevent the complications of congenital hypothyroidism. Transplacental passage of TSH-binding inhibitory immunoglobulins(TBII) may result in transient congenital hypothyroidism. Transient neonatal hypothyroidism was found in a daughter of 25-yr-old mother who was receiving levothyroxine for primary hypothyroidism due to Hashimoto's thyroiditis. The neonate was treated with thyroxine which was discontinued at 24 months of age. Thyroid scanning during the neonatal period failed to identify functional thyroid tissue, suggesting thyroid agenesis, whereas thyroid scan performed on subsequent follow-up revealed a normal gland. Sequential measurements of serum autoantibodies directed towards the TSH receptor were made in the patient and her mother. High titers of blocking antibodies were present in the mother(TBII, 82.1%) and newborn(TBII, 85.5%) at 19 days after birth. The levels remained persistently high in the mother, whereas they declined and undetectable in the patient at 23 months of age. The above laboratory and clinical data were compatible with blocking nature of TBII, resulting in transient neonatal hypothyroidism and an athyreotic appearance on scan. The TBII measurement can be a useful predictor of neonatal hypothyroidism as well as confirming the nature of the disease in newborn.