A term neonate weighing 3 kg is confirmed to have primary congenital hypothyroidism (TSH 120 mIU/L, free T4 0.5 ng/dL). Treatment with oral levothyroxine is started. What is the recommended initial daily dose?

• A 2 to 4 microgram/kg
• B 5 to 8 microgram/kg
• C 10 to 15 microgram/kg ✓
• D 20 to 25 microgram/kg

Explanation

Current guidance recommends starting full replacement at 10 to 15 microgram/kg per day in infants to normalize T4 as rapidly as possible and protect neurodevelopment; for this 3 kg baby that is 30 to 45 micrograms daily. Lower doses such as 5 to 8 microgram/kg are used for mild or transient elevations and risk undertreatment. Doses above 15 microgram/kg carry a risk of overtreatment affecting craniosynostosis and temperament.

Reference: Nelson Textbook of Pediatrics, 22nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.