Congenital hypothyroidism

• Published in: Indian journal of endocrinology and metabolism Vol. 19; no. 2; pp. 221 - 227
• Main Authors: Agrawal, Pankaj, Philip, Rajeev, Saran, Sanjay, Gutch, Manish, Razi, Mohd Sayed, Agroiya, Puspalata, Gupta, Keshavkumar
• Format: Journal Article
• Language: English
• Published: India Medknow Publications and Media Pvt. Ltd 01.03.2015; Medknow Publications & Media Pvt. Ltd; Medknow Publications & Media Pvt Ltd; Wolters Kluwer Medknow Publications
• Subjects: Age; Births; Care and treatment; Congenital hypothyroidism; Defects; Developing countries; Diagnosis; Dyshormonogenesis; Genes; Health care; Hypothyroidism; Intellectual disabilities; Iodine; Laboratories; LDCs; Levothyroxine; Medical screening; Metabolism; Mutation; neonatal screening; Newborn babies; Review; Risk factors; Transcription factors; India; North America; Levothyroxine; Dyshormonogenesis; neonatal screening
• ISSN: 2230-8210; 2230-9500
• DOI: 10.4103/2230-8210.131748

Congenital hypothyroidism (CH) is the one of the most common preventable cause of mental retardation. In the majority of patients, CH is caused by an abnormal development of the thyroid gland (thyroid dysgenesis) that is a sporadic disorder and accounts for 85% of cases and the remaining 15% of cases are caused by dyshormonogenesis. The clinical features of congenital hypothyroidism are so subtle that many newborn infants remain undiagnosed at birth and delayed diagnosis leads to the most severe outcome of CH, mental retardation, emphasizing the importance of neonatal screening. Dried capillary blood is used for screening and it is taken from heel prick optimally between 2 and 5 days of age. Blood spot TSH or thyroxine (T4) or both are being used for CH screening in different programs around the world. Neonates with abnormal thyroid screening tests should be recalled immediately for examination and a venipuncture blood sample should be drawn for confirmatory serum testing. Confirmatory serum should be tested for TSH and free T4, or total T4. Serum TSH and T4 undergo dynamic changes in the first weeks of life; it is important to compare serum results with age-normal reference ranges. Treatment should be started promptly and infant should be rendered euthyroid as early as possible, as there is an inverse relationship between intelligence quotient (IQ) and the age at diagnosis. Levothyroxine (l-thyroxine) is the treatment of choice and American academy of pediatrics and European society of pediatric endocrinology recommend 10-15μgm/kg/day as initial dose. The immediate goal of therapy is to normalize T4 within 2 weeks and TSH within one month. The overall goal of treatment is to ensure growth and neurodevelopmental outcomes as close as possible to their genetic potential.