The Heel Test
Ateneo Libre de Benalmádena
CONGENITAL HYPOTHYROIDISM: TEST OF THE HEEL
- Congenital Hypothyroidism (HC) is the most frequent cause of preventable mental retardation.
- The HC is a congenital deficiency of the thyroid gland that left to its natural evolution, causes physical and mental retardation, serious and irreversible.
- Before its eradication in developed countries it was known as cretinism.
- The important thing is to emphasize that if the HC is treated in time normal development is achieved.
- The treatment, which has to be for life, is easy and cheap.
- The central Nervous System of the human species reaches the fastest growth rate during the first week of life.
- In the perinatal period up to 500,000 neuronal connections per second are produced, for which thyroid hormone (thyroxine or T 4 ) is needed.
- The IQ of Congenital Hypothyroids treated correctly is not different from that of the general population.
- The Neonatal Screening Program for HC has been imposed because it is economically profitable.
- The incidence of HC is one for every 2,300 newborns, which amounts to about 8 to 10 cases each year in Malaga and about 200 in all of Spain.
THE TEST OF THE HEEL
- To detect the disease early, a test was used that was developed in Malaga and Zürich between 1974-76 and consists in measuring TSH (Thyroid Stimulating Hormone) in a drop of blood extracted from the heel and collected on a filter paper.
- TSH is the pituitary hormone responsible for stimulating the thyroid.
- What TSH does is tell the thyroid to make thyroxine.
- If the thyroid works normally, it answers the pituitary gland, through thyroxine, telling it that it is already working; but if it does not answer because it is failing, the pituitary gland continues to send the operating order through the TSH.
- When the thyroid does not work and does not produce thyroid hormone (thyroxine or T 4 ), which will slow down the production of TSH, it increases in blood.
- Therefore, when TSH is elevated in the blood, it is interpreted that the thyroid does not work well, that is, it does not respond to the TSH commands.
- The results should be ready as soon as possible because the treatment should begin within the first week of life.
- The treatment consists of administering the thyroid hormone (thyroxine or T 4 ) that the HC thyroid does not produce in sufficient quantity (therefore it does not slow down the TSH).
- The technique for measuring TSH uses delicate reagents.
- Some laboratory equipment is also required, such as photocolorimeters, centrifuges, refrigerators, automatic pipettes, etc.
SALVADOR PERAN MESA is Professor of Physiology and Biochemistry at the Faculty of Medicine of the University of Málaga. He has been the first protocolist, and therefore the introducer, of the Heel Test in clinical practice in Spain, which is routinely followed in every hospital in the country, which makes him worthy of our recognition.
He is a prolific and committed writer, author of numerous books and related writings, beyond his specialty, to social coexistence.