علاج نقص اليود الخلقي مع انخفاض fT4 وانخفاض أو طبيعي TSH (قصور الغدة الدرقية المركزي الخلقي)

DOI: 10.1089/thy.2020.0333

• If the serum fT4 is low, and TSH is low, normal or slightly elevated, the diagnosis central CH should be considered.
• In neonates with central CH, we recommend to start LT4 treatment only after evidence of intact adrenal function; if coexistent central adrenal insufficiency cannot be ruled out, LT4 treatment must be preceded by glucocorticoid treatment to prevent possible induction of an adrenal crisis.
• In severe forms of central CH (fT4 < 5 pmol/L), we also recommend to start LT4 treatment as soon as possible after birth at doses like in primary CH (at least 10 μg/kg per day, see Section 3.1), to bring fT4 rapidly within the normal range.
• In milder forms of central CH, we suggest starting treatment at a lower LT4 dose (5–10 μg/kg per day) to reduce the risk of overtreatment.
• In newborns with central CH, we recommend monitoring treatment by measuring fT4 and TSH according to the same schedule as for primary CH; serum fT4 should be kept above the mean/median value of the age-specific reference interval; if TSH is low before treatment, subsequent TSH determinations can be omitted.
• The (biochemical) LT4 treatment aim is bringing and keeping the fT4 concentration in the upper half of the age-specific fT4 reference interval.