A 10-day-old female neonate is found on national newborn screening to have TSH 180 mIU/L and free T4 of 0.4 ng/dL. She is clinically asymptomatic with no goitre. The most appropriate management is:

• A Repeat TSH at 6 weeks before starting treatment
• B Start iodine supplementation to the mother
• C Perform thyroid scintigraphy before initiating therapy
• D Commence levothyroxine 10–15 mcg/kg/day immediately ✓

Explanation

Congenital hypothyroidism (CH) with elevated TSH >40 mIU/L and low T4 confirmed on newborn screen requires immediate levothyroxine at 10–15 mcg/kg/day (usually 37.5–50 mcg/day) to prevent irreversible intellectual disability. Delaying for repeat testing or imaging is inappropriate given the urgency; IQ loss occurs with each week of untreated CH. Thyroid scintigraphy can be performed after 2–3 years to determine etiology without compromising treatment. Iodine deficiency is a rare cause in India where universal salt iodization exists.

Reference: Ghai Essential Pediatrics, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.