Childhood hypothyroidism
The infantile hypothyroidism affects between one and three percent of the child population. After birth, most congenital hypothyroidism can be diagnosed and treated quickly. Thyroid hormones are necessary for the development of the central nervous system. In such a way that the lack of these hormones in the last months of gestation and first days of life, causes an irreversible mental retardation.
The important role of thyroid hormones
That is why, for the correct development of the fetus, every pregnant woman must have normal thyroid hormone values, which means having adequate levels of iodine. In addition, thyroid hormones are necessary for the proper functioning of certain organs and systems (metabolism, heart, digestive system, reproductive system, etc.), which are affected when you do not have adequate levels.
In the pediatric population, hypothyroidism is the most frequent thyroid dysfunction, with a prevalence-according to the latest published studies-of between 1% and 3%. On the other hand, it is estimated that 5% of children have mild or subclinical hypothyroidism. The diagnosis of the largest number of infantile hypothyroidism mild is due to the completion of the diagnosis and the initiation of treatment at an appropriate time, and to the improvement of the detection of some false negative cases, such as twins, thanks to the repeated heel test at 15 days.
Diagnosis of childhood hypothyroidism
Through the diagnosis in childhood it is possible to prevent future alterations of the thyroid in adulthood. In fact, more and more works of thyroid pathology are being published in adulthood whose origin is in childhood.
The diagnosis of congenital hypothyroidism is well documented and is not technically complicated, since the level of TSH in the whole blood sample is simply determined (heel test performed in Neonatal Screening). The study of thyroid dysfunction by the biochemistry laboratory is also not complex.
What does present more complications is knowing the cause that causes this dysfunction. In this sense, it would be very useful to know which genes are responsible for many of these thyroid diseases, both for diagnosis and treatment.
Types of childhood hypothyroidism
There are two differentiated forms of hypothyroidism. On the one hand congenital, in which in turn differentiate those that have genetic origin and need treatment throughout their lives, and transients, in which the origin of thyroid dysfunction may be due to the mother, or because of certain thyroid pathologies, or for certain treatments, likewise an excess or defect of iodine could be the cause. In these cases the treatment can be suspended once the correct thyroid function has been recovered. The most affected population are premature children.
On the other hand, there are acquired ones, whose prevalence increases with age. The symptoms in this type depend on the degree of dysfunction, although the main ones are short stature, obesity, constipation, dry skin and drowsiness. In this group, the clearly pathological hypothyroid tumors usually have an autoimmune origin, not so the subclinical ones that have a genetic origin in 29% of the cases.
Lines of work in hypothyroidism
The detection of congenital hypothyroidism through the measurement of TSH in the capillary blood of the newborn obtained in the heel test has yielded spectacular results in the prevention of the onset of the disease, however several aspects remain pending whose better knowledge we will allow to detect it and diagnose it better.
Another important issue is to deepen the knowledge of transient hypothyroidism, since these temporary alterations of the normal functioning of the thyroid gland create a high degree of anxiety in families and its pathophysiology is not well known yet.
Teresa Pereda
Advice: Perinatal Diagnosis Commission of the Spanish Society of Clinical Biochemistry and Molecular Pathology (SEQC)
