Persistently raised thyroid stimulating hormone in adequately treated congenital hypothyroidism on long-term follow-up.
OBJECTIVE
To determine the percentage of patients with inappropriate secretion of TSH (ISTSH) in a large cohort of patients with congenital hypothyroidism (CH), and to examine a probable influence of the pretreatment T4 or TSH levels and the etiology of CH on ISTSH by describing the clinical features of these patients.


METHODS
We retrospectively examined the records, including anthropometric data, clinical findings, and thyroid function tests (TFT), of 500 children diagnosed with CH. Inclusion criteria of ISTSH were appropriate doses of L-T4, improvement of clinical findings, normalization of serum total T4 levels and persistently high TSH concentrations. A group of patients who demonstrated adequate suppression of TSH (<6 mU/l) with therapy among 500 CH patients were chosen randomly as a control group. Both groups were compared with regard to the etiology of CH, and TFT at baseline and during the treatment period.


RESULTS
Overall, 27 (5.4%) out of the 500 patients with CH had ISTSH. Nine patients (1.8%) with ISTHS did not show TSH normalization during the follow-up period. Four out of 27 patients with ISTSH had organic lesions (three empty sella, one corpus callosum agenesis) on cranial imaging. No statistically significant difference was found between the groups for etiological classification. The pretreatment T4 and TSH levels in ISTHS and control groups were not significantly different.


CONCLUSIONS
Our results suggest that a minority (5.4%) of adequately treated children with CH have persistently raised TSH levels. The delay in normalization of TSH is not related to pretreatment T4 and TSH values or the etiology of CH.
Department of Pediatric Endocrinology, Ankara University, School of Medicine, Ankara, Turkey. cengizkara68@yahoo.com
Cengiz
C
Kara
Gönül
G
Ocal
Merih
M
Berberoğlu
Zeynep
Z
Siklar
Pelin
P
Adiyaman
D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003409:Congenital Hypothyroidism / Q000097:blood* / Q000188:drug therapy*; D004563:Electrochemistry; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008163:Luminescent Measurements; D008297:Male; D015997:Neonatal Screening; D012189:Retrospective Studies; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood / Q000627:therapeutic use*; D013997:Time Factors
D013972:Thyrotropin; D013974:Thyroxine