The evaluation of follow-up and prognosis the patients with congenital hypothyroidism in Division of Endocrinology, Department of Pediatrics, Faculty of Medicine, Dokuz Eylul University

Aim: Congenital hypothyroidism (CH) is one of the most frequent preventable reasons of mental retardation in children. The entity can present with thyroid dysgenesis, alterations in synthesis and effect of thyroid hormones, central hypothyroidism or transient hypothyroidism. Here, the etiological factors, diagnostic approaches, and dose and duration of treatment were compared between cases with transient and permanent hypothyroidism with respect to prognosis.Subjects and Methods: One hundred and twelve patients (59 males, 63 females) who received treatment with the diagnosis of CH between 1997 and 2007 in Division of Endocrinology, Department of Pediatrics, Faculty of Medicine, Dokuz Eylul University were included in the study. The records of the patients were reviewed retrospectively. Data of all patients regarding age, gestational age, height SDS, weight SDS, medical family history, symptoms and age at the time of diagnosis were evaluated. Total T4, total T3, free T4, free T3, and TSH levels obtained at the onset of the treatment, by the end of first, second, and third years of treatment and, in whom treatment was ceased, after one month of discontinuation. The cases with thyroid ultrasonography and Tc 99m scintigraphy were noted. The results of the cases underwent WISC-R or Denver developmental tests, according to their age, were obtained. Those evaluations were made by a psychologist working in Department of Pediatric Psychiatry. The statistical analysis of the data was made with SPSS software, version 11.5. A p-value of <0.05 was chosen to represent statistical significance.Results: When the cases were evaluated, the rate of symptoms at the time of diagnosis was found to be 20.4% in cases with permanent CH while this rate was 3.4% in cases with transient CH and this difference was statistically significant (p=0.041). The most frequent presenting symptom was prolonged jaundice in both groups. The rate of normal thyroid ultrasonography and scintigraphy studies was significantly higher in cases with transient CH compared to those with permanent CH (p<0.001).Serum TSH and total T4 levels at the time of diagnosis were found to be significantly higher in permanent CH group in comparison to transient CH group (p<0.001). Statistically significant difference was present between the groups regarding treatment doses both at the onset of the treatment and by the end of first, second, and third years of therapy. Significant difference was detected between the permanent and transient CH groups regarding the time needed for TSH decrease to below 5 mIU/mL following L-thyroxine treatment (p=0.004). Significant difference was present between the two groups regarding the TSH and FT4 levels obtained one month after discontinuation of the treatment that was tried at the age of three (p<0.0001 and p=0.041, respectively). When the association between age at the time of initiation of treatment and results of Denver developmental test was analyzed, all of the patients, to whom the treatment was started after two months of age due to a group of reasons, were found to be negatively influenced while none of the patients who were started treatment before two months of age had abnormal results and this difference was noted to be statistically significant (p=0.016).Conclusion: The noticeably high frequency of transient CH in our region leads to the result that some of the patients were considered to have permanent hypothyroidism and had to be unnecessarily treated with L-thyroxine for a long time. In particular, normal thyroid ultrasonography and scintigraphy and TSH and T4 levels at the time of diagnosis have important impact in differential diagnosis. Additionally, the importance of screening program for our country emerges once more given the late admission to medical care observed in some cases with CH during our study period.Key Words: Congenital hypothyroidism, thyroid hormone, transient hypothyroidism