He congenital hypothyroidism (HC) is an endocrinological disease that causes a decrease in the biological activity of thyroid hormones.
In some newborns this occurs well because they cannot produce enough hormones, because the gland does not work or because they were born without this gland.
Congenital hypothyroidism is the most frequent cause of preventable mental retardation in pediatrics. Brain damage directly depends on the time elapsed from the onset of hypothyroidism and the time of treatment.
For this reason, newborns who are detected and start treatment in the first days of life reach a normal or near-normal IQ, reducing morbidity, mortality and possible disabilities associated with said disease.
And this early detection is done thanks to the newborn screening testspopularly known as in newborns.
Increased incidence of congenital hypothyroidism
These types of tests have been carried out in Spain since 1978. But, despite this, in the last decade the incidence of this pathology has been increasing.
This is due, as explained by the doctor Rosa Mª López Galerafrom the Biochemistry and Molecular Genetics Service of the Hospital Clínic of Barcelona and the Neonatal Screening Program of Catalonia, to various factors.
“The greater risk of suffering from it in the premature newborn, low birth weight and univiteline twins (whose number has increased with advances in neonatology), or detection strategies that favor the detection of moderate forms of this pathology”.
Symptoms
Thanks to the heel test, performed 48-72 hours after birth and with which a few drops of blood are obtained, it is very rare to see symptoms of congenital hypothyroidism. Screening makes it possible to detect it and quickly start treatment.
Even so, as they explain from the , “thyroid hormone deficiency can also occur in older babies or young children, even if the tests at birth were normal.”
In these cases, the child may present symptoms such as:
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breathing difficulties
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Slow or irregular heartbeat (bradycardia).
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The skin takes on a bluish color (cyanosis).
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Persistent jaundice.
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umbilical hernia.
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Lethargy.
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Drowsiness.
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Lack of appetite.
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hoarse cry
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Constipation.
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Presence of a large open anterior or posterior fontanelle.
Consequences of congenital hypothyroidism
As indicated by the doctor Hugo Rochafrom the Neonatal Screening, Metabolism and Genetics Unit of the Department of Human Genetics of the Instituto Nacional de Saúde Doutor Ricardo Jorge de Portugal, “if it is not diagnosed and treated early (through hormone replacement treatment) the sequelae can be permanent”.
Among these sequels, the expert lists the “rdelayed growth and physical and mental development and that is manifested by short stature and short extremities, persisting infantile proportions and delayed bone maturation and dentition”.
“Intellectual retardation can be of variable intensity, from profound cognitive deficits to mild learning disorders.”
Advances and challenges in neonatal screening
Experts classify congenital hypothyroidism into three large groups. On the one hand, there is the primary one, whose cause is in the thyroid gland itself. On the other, the central one (the disorder is located in the pituitary gland or in the hypothalamus). And lastly the group of peripheral congenital hypothyroidisms.
Well then, as explained by , thanks to advances in this field, not only primary congenital hypothyroidism is currently detected, but also central hypothyroidism.
It is even possible to diagnose other moderate or transient secondary forms that may benefit from early diagnosis and treatment.
But the rest of the specialists in Laboratory Medicine go further. For doctor Rocha, “advances in the detection of this disease should be aimed at developing new strategies with more optimized adjustmentsimprovement of analytical methods, the inclusion of other markers in the detection, or the application of more specific analytical tools”.