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Context: Congenital hypothyroidism (CH) is the most prevalent endocrine disorder in the newborn and is routinely treated with life-long levothyroxine replacement therapy. Although several studies have demonstrated that such therapy may impact on the cardiovascular system, little is known with regard to the effects of long-term levothyroxine administration in patients with CH. Objective: The aim of the current study was to evaluate whether long-term levothyroxine replacement therapy in young adults with CH is associated with cardiovascular abnormalities. Patients and Methods: Thirty young adults with CH aged 18.1 ± 0.2 yr and 30 age- and sex-matched controls underwent cardiac and carotid Doppler ultrasound and symptom-limited cardiopulmonary exercise testing. Hypothyroidism was diagnosed by neonatal screening, and levothyroxine treatment was initiated within the first month of life and carefully adjusted to maintain TSH levels in the normal range and free T4 in the high-normal range. Results: Compared with controls, hypothyroid patients exhibited left ventricular diastolic dysfunction, impaired exercise capacity, and increased intima-media thickness. At multiple regression analysis, the number of episodes of plasma TSH levels less than 0.5 mU/liter and greater than 4.0 mU/liter from the age of 1 yr onward, and mean TSH plasma levels during puberty were independent predictors of diastolic filling and cardiopulmonary performance indexes (multiple r values: 0.61–0.75). Conclusions: Long-term levothyroxine treatment in young adults with congenital hypothyroidism is associated with impaired diastolic function and exercise capacity and increased intima-media thickness.

Background Occasional and transient increase in liver enzymes is reported during growth hormone (GH) treatment in girls with Turner syndrome (TS). Methods Retrospectively, the specific role of GH treatment on liver and muscular enzymes was evaluated in 78 patients (48 boys; age range 4.0-20.8 years) affected by GH deficiency (GHD) who had been treated with GH for at least 1 year (range: 1-15 years). All patients had normal serum levels of liver and muscular enzymes before GH therapy was started. Results A clinically asymptomatic and mild increase in serum transaminase levels was observed in 6 of 78 patients with GHD during GH treatment; 3 (3.8%) of the patients showed an isolated, transitory and self-limiting increase in serum liver transaminase levels which was noticed 6 to 12 months after GH treatment was started, and normalized spontaneously within 3 to 6 months, without stopping the therapy. Three additional patients showed a transitory mild increase both in aspartate aminotransferase (AST) and creatine phosphokinase (CK) which also normalized spontaneously within 3 to 6 months. The increase in transaminase levels was not related to the brand of GH preparations nor to the dosage administered. Conclusions A mild, transient, self-limiting increase in serum transaminase may occur during GH treatment. Concomitant determination of CK serum levels may quickly differentiate muscular from hepatic hypertransaminasemia. Except for persistent cases, this condition does not generally require further investigations.

OBJECTIVE: To evaluate longitudinal growth, pubertal development and final height in patients with congenital hypothyroidism (CH) detected by a neonatal screening programme, and to identify factors potentially affecting growth outcome. PATIENTS: Fifty-five patients (41 females) detected by neonatal screening and followed longitudinally from the time of diagnosis and treatment (25+/-5 days) up to the age of 17+/-0.5 years were evaluated retrospectively. RESULTS: Pubertal development began and progressed normally in both males and females. In boys, a testicular volume of 4 ml was reached at 11.3+/-1.0 years. In girls breast enlargement (B2) occurred at a mean age of 10.3+/-1.2 years and the mean age of menarche was 12.5+/-1.2 years. The onset and the progression of puberty were independent of the aetiology, the severity of CH and the timing of the beginning of treatment. Girls treated with an initial amount of L-thyroxine (L-T4) greater than 8 microg/kg per day showed an earlier onset of puberty (B2 9.4+/-0.9 years; menarche 11.5+/-0.8 years) compared with girls treated with a lower initial dose of L-T4 (B2 10.5+/-1.2 years; menarche 12.6+/-1.2 years; P