Hypothyroidism%20(pediatric) Treatment

• Treatment should be started if obtained capillary thyroid stimulating hormone (TSH) concentration on neonatal screening is ≥40 mU/L and another venous blood sample has been obtained
• Treatment may be delayed until thyroid function test results are available if the capillary TSH concentration is <40 mU/L
• Patients with low venous free thyroxine (FT4) concentrations and venous thyroid stimulating hormone (TSH) concentration of >20 mU/L should receive treatment immediately
• Transient hypothyroidism (eg subacute and drug-induced thyroiditis) should be treated during the hypothyroid phase
• Newborns with elevated TSH should be treated empirically with thyroid hormone replacement until 2 years of age to avoid permanent cognitive deficits due to hypothyroidism
  • Treatment started within 2 weeks after birth increases better optimal long-term outcome

Treatment Goals

• To restore a euthyroid state by normalizing the serum TSH
• To improve the hypothyroid symptoms and decrease goiter size
• To restore normal growth, development and normal pubertal progression in children

Levothyroxine (T₄)

• Used as replacement therapy for hypothyroidism
• Available in pure form, stable and inexpensive, with half-life of 7 days
• Dose varies depending on the age, body weight, cardiac status, and disease severity
  
  • Neonates and children require larger replacement doses due to their rapid metabolism
  • Infants with very low total T₄ or FT₄ concentration prior to initiation of therapy should receive the highest initial dose
• In most patients with hypothyroidism, treatment can be initiated with the full estimated dose requirement and some patients with partial replacement with gradual dose increments adjusted based on serum TSH as the goal