Congenital Hypothyroidism
Inborn Thyroid Hormone Deficiency Disorder
Primary risk age: Neonates (Screened at birth; symptoms develop in the first few weeks if untreated)
- Urgency
- Severe
- Typical age
- Neonates (Screened at birth; symptoms develop in the first few weeks if untreated)
- Body system
- Endocrine & Metabolic
Typical course: This is a lifelong genetic or developmental endocrine disorder requiring continuous daily hormone replacement.
Reviewed against AAP · CDC · WHO · NHS guidance Last reviewed 2026-06-13
1. Summary & Pathophysiology
Inborn Thyroid Hormone Deficiency Disorder
Pathophysiology (Development Path)
The absence or failure of the thyroid gland to produce adequate thyroxine (T4). Thyroxine is essential for early brain development and skeletal growth. Deficiencies lead to irreversible intellectual disability and growth failure.
Primary Causes & Etiology
Thyroid dysgenesis (absence or underdevelopment of the thyroid gland) in 85% of cases; thyroid dyshormonogenesis (inborn errors of thyroid hormone synthesis) in 15%.
2. Symptom Continuum
- Early Onset Signs
Term infants are often asymptomatic due to maternal thyroid hormone crossing the placenta. A prolonged physiological jaundice is the earliest indicator.
- Progressive Phase
Poor feeding, lethargy (sleeping too much), constipation, hypothermia, cold extremities, and a hoarse or weak cry.
- Severe Indicators
Classic cretinism: coarse facial features, large protruding tongue (macroglossia), umbilical hernia, dry skin, wide cranial sutures, and severe developmental delay.
3. Clinical Verification
Newborn screening showing an elevated Thyroid Stimulating Hormone (TSH) and low free thyroxine (T4) from a heel stick blood spot. Confirmed with serum thyroid labs.
4. Care & Elements Plan
Primary Care Treatment Plan
Initiate daily oral replacement of Levothyroxine immediately. Dosing must begin within the first 2 weeks of life to prevent developmental delay. Monitor TSH and free T4 levels closely to adjust dosage as the child grows.
Home Support Elements
Administer the tablet crushed in a small amount of breast milk or water at the same time every day. Never mix it with soy formula or iron/calcium supplements, which impair absorption.
Generic Active Ingredients (No Brands)
- Levothyroxine sodium (generic active thyroid hormone replacement ingredient).
Lists active elements only. Never administer self-designed therapies.
5. Doctor Critical Lines
Critical Thresholds: When to See a Doctor
Consult a pediatrician if newborn screening results are delayed, or if a young infant develops persistent jaundice, constipation, or sleeps excessively.
6. Vaccine & Prevention
Routine Prophylaxis (Prevention)
Ensure adequate maternal iodine intake during pregnancy; no direct prevention exists for dysgenesis.
Immunization Context
No specific immunizations are associated with this endocrine disorder; follow standard schedules.
7. Timelines & Outlook
Active Timeline
This is a lifelong genetic or developmental endocrine disorder requiring continuous daily hormone replacement.
Expected Prognosis
Excellent if treatment is started within the first 2 weeks of life. Untreated infants develop severe, irreversible intellectual disabilities.
Potential Untreated Complications
Intellectual disability, short stature, delayed bone age, cardiac enlargement, and motor coordination problems.
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