NCLEX Review Guide: Neonatal Hypothyroidism

Understanding Congenital Hypothyroidism

• Congenital hypothyroidism occurs when the thyroid gland fails to produce adequate thyroid hormones (T3 and T4) from birth, affecting 1 in 3,000-4,000 newborns. Early detection through newborn screening is critical as untreated hypothyroidism leads to irreversible intellectual disability and growth retardation.
• The condition can result from thyroid dysgenesis (absent or underdeveloped gland), dyshormonogenesis (enzyme defects), or maternal factors like iodine deficiency. Most affected newborns appear normal at birth due to maternal thyroid hormones crossing the placenta.

Assessment Findings

• Early signs (first few weeks): Prolonged physiologic jaundice lasting >2 weeks, feeding difficulties, excessive sleeping, constipation, and hypothermia. The infant may appear lethargic and have poor muscle tone.
• Later signs (if untreated): Macroglossia (enlarged tongue), umbilical hernia, coarse facial features, dry skin, brittle hair, and developmental delays. Growth retardation becomes apparent with short stature and delayed fontanelle closure.

Medication Administration

1. Administer levothyroxine (Synthroid) as the standard treatment, typically 10-15 mcg/kg/day orally once daily in the morning.
2. Crush tablet and mix with small amount of breast milk, formula, or water - avoid mixing with soy formula or iron supplements as they decrease absorption.
3. Give medication 30-60 minutes before feeding for optimal absorption and maintain consistent timing daily.
4. Monitor for signs of overtreatment including tachycardia, irritability, poor weight gain, and advanced bone age.

Family Education & Support

• Educate parents that lifelong hormone replacement therapy is necessary and emphasize the importance of medication compliance to prevent intellectual disability. Stress that with proper treatment, children can achieve normal growth and development.
• Teach proper medication administration techniques and storage requirements, emphasizing consistency in timing and avoiding certain foods/medications that interfere with absorption. Schedule regular follow-up appointments for monitoring and dose adjustments.