Thyroid function in the neonatal period
- An estimated 1% of babies with Down syndrome have a raised TSH on newborn screening, but classical congenital hypothyroidism due to thyroid dysgenesis is not common.
- Raised TSH should prompt further investigation, and consideration of treatment with thyroxine.
- Borderline thyroid dysfunction in the neonate may be transient, and when treatment is started in these cases , treatment should be stopped after the age of 2 years and thyroid function reassessed off treatment.
- At present there is no hard evidence to justify routinely treating infants with Down syndrome with thyroxine, if they have normal thyroid function.
Thyroid function beyond the neonatal period
- Thyroid dysfunction , mainly hypothyroidism occurs more commonly in people with Down syndrome at all ages, when compared with the general population.
- The prevalence of autoimmune thyroiditis increases with age in Down syndrome.
- Clinical diagnosis of hypothyroidism may be unreliable in Down syndrome because of overlap with features commonly seen in the syndrome e.g. dry skin, thin hair and constipation.
- Screening for thyroid dysfunction is required throughout life.
- Capillary TSH testing is a practical reliable method. This can be done by fingerprick samples and on the same cards as used for newborn screening.
- Mild elevation of TSH with normal fT4 and no symptoms may not require treatment.
- Hyperthyroidism is less common than hypothyroidism, but occurs more frequently than in the general population.
Guideline for Basic Essential Medical Surveillance
DSMIG’s evidence-based guideline for basic essential medical surveillance.
Last updated: 2001
Presentations at DSMIG Meetings
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Book Chapter -Â Endocrine Disorders – Thyroid Disorder
Malcolm Donaldson and Kath Leyland
Edited by Richard Newton , Shiela Puri and Liz Marder