ABSTRACT

Congenital hypothyroidism (CH) is still the most common cause of mental retardation. ln this study, etiology, laboratory findings, treatment doses, durations of permanent and transient CH cases were compared.

106 patients (42 female, 64 male) who had been treated for CH for at least 3 years were included. Patients’ files were retrospectively scanned. TSH, FT4, FT3, height, weight and treatment doses, findings at the first time of diagnosis, first, second, and third year of treatment and 4-6 weeks after the treatment was ended, were noted.

Permanent CH was found in 41.5% of patients and transient CH was found in 58.5% of patients. The most common cause of permanent hypothyroidism was thyroid dysgenesis (34%). dyshormonogenesis (38.7%) was the most frequent cause in patients with transient CH. The most common symptoms were hyperbilirubunemia and constipation. 27 % of the patients were referred to the outcome screening program and 27% of the patients were visited for routine control. Serum TSH, FT4 and FT3 levels at diagnosis were not significantly different between the groups (p = 0.955, p = 0.532, p = 0.23). The level of thyroglobulin was significantly higher in the transient CH group (p =0,026). FT3 levels of patients with permanent CH were significantly lower during follow-up.( p= 0.003, p = 0.017, p = 0.032).

In our study, it is found that the ratio of transient CH is higher and most of the transient cases were attributed to dyshormonogenesis. It is shown that the thyroid hormone levels at the time of diagnosis is not significantly different in the differential diagnosis of permanent and transient CH. However, it is concluded that the need for higher dose in the treatment during follow up and the higher TSH levels, and the lower fT3 levels can be used in diagnosis of permanent CH.