Low free thyroxine and normal thyroid-stimulating hormone in infants and children: possible causes and diagnostic work-up

Conclusion: Here we discuss a number of rare congenital HPT axis disorders in which TSH is normal, but FT4 is low, and provide a clinical algorithm to distinguish between these disorders.What is Known:• A single thyroid-stimulating hormone (TSH) measurement is an appropriate screening method for primary hypothyroidism.• For central hypothyroidism and rare thyroid hormone receptor and transporter defects a free thyroxine (FT4) measurement is essential for the diagnosis because TSH is usually normal.What is New:• Here we present a new problem-oriented clinical algorithm including a diagnostic flow-chart for low FT4 and normal TSH in infants and children.
Source: European Journal of Pediatrics - Category: Pediatrics Source Type: research