Konjenital Hipotirodi: Tanı, Tedavi ve Yenidoğan Tarama Programının Önemi
Özet
Konjenital hipotiroidi (KH), yenidoğan döneminde tiroid bezinin gelişimsel anomalileri veya hormon sentez kusurları nedeniyle ortaya çıkan, erken tanı konulup tedavi edilmediğinde geri dönüşümsüz zeka geriliği ve büyüme yetersizliğine yol açan kritik bir endokrin bozukluktur. Hastalık yenidoğan döneminde genellikle nonspesifik bulgular sergilediği için klinik olarak gözden kaçabilmektedir; bu durum, topuk kanından TSH veya T4 ölçümüne dayanan tarama programlarının hayati önemini ortaya koymaktadır. Türkiye’de 2006 yılından bu yana ulusal tarama programı kapsamında yürütülen süreç, bebeklerin yaşamın ilk haftalarında tespit edilmesini hedeflemektedir. Prematüreler ve düşük doğum ağırlıklı bebeklerde fizyolojik immatürite nedeniyle gecikmiş TSH yükselmesi görülebilmekte, bu da tarama testlerinin takibinde hassasiyet gerektirmektedir. Tanı doğrulaması serum tiroid hormon düzeyleri, ultrasonografi ve sintigrafi gibi yöntemlerle yapılarak etiyolojide kalıcı primer, geçici veya santral KH ayrımı gerçekleştirilir. Tedavinin temelini, tanı konur konmaz vakit kaybetmeden başlanan yüksek doz sodyum L-tiroksin (Na-L-T4) replasman tedavisi oluşturur. Postnatal ilk haftalarda başlanan optimum hormon replasmanı ve düzenli takiple, hastaların uzun dönem nörobilişsel, motor ve fiziksel gelişim düzeylerinin sağlıklı akranlarıyla benzer seviyelere ulaştığı ve kalıcı morbiditelerin büyük ölçüde önlendiği kohort çalışmalarıyla kanıtlanmıştır.
Congenital hypothyroidism (CH) is a critical endocrine disorder arising from developmental anomalies of the thyroid gland or defects in thyroid hormone synthesis, leading to irreversible intellectual disability and growth restriction if not diagnosed and treated promptly. Since the disease often presents with non-specific symptoms during the neonatal period, clinical detection can be challenging, underscores the vital importance of newborn screening programs based on heel-prick TSH or T4 measurements. Integrated into Turkey's national screening framework since 2006, this program aims to identify affected infants within the first weeks of life. Premature and low-birth-weight infants may exhibit delayed TSH elevation due to hypothalamic-pituitary-thyroid axis immaturity, requiring careful monitoring. Diagnostic confirmation involves evaluating serum thyroid hormones, ultrasonography, and scintigraphy to differentiate between permanent primary, transient, or central CH etiologies. The cornerstone of management is immediate initiation of high-dose sodium L-thyroxine (Na-L-T4) replacement therapy upon diagnosis. Cohort studies demonstrate that optimum hormone replacement started in early postnatal weeks, combined with regular follow-ups, enables long-term neurocognitive, motor, and physical development to match healthy peers, successfully preventing permanent morbidities.
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