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OBJECTIVES: To test whether early treatment with a high initial dose of levothyroxine can prevent suboptimal mental development in all neonates with congenital hypothyroidism (CH). STUDY DESIGN: Sixty-one patients, 27 with severe CH and 34 with mild CH, were treated either early (<13 days) or late (> or =13 days) with either a high initial dose of levothyroxine (> or =9.5 microg/kg/d) or a low initial dose (<9.5 microg/kg/d). With these criteria, 4 treatment groups were formed. The results of the Bayley test, performed at the age of 10 to 30 months and expressed as mental developmental index (MDI) and psychomotor developmental index (PDI), were related to socioeconomic status, treatment group, initial free thyroxine (FT(4)) concentration, and mean FT(4) concentration during the first 3 months of treatment (FT(4)-A) and the ensuing 9 months (FT(4)-B). RESULTS: Mean (+/- SD) MDI was 113 +/- 14, and mean PDI was 114 +/- 12. In the severe CH group, only the patients treated early with a high initial dose had normal MDI scores (124 +/- 16), whereas the scores of the other groups ranged from 97 to 103. In contrast, all patients in the mild CH group had normal scores (range, 122-125), except those in the group treated late with a low initial dose, whose score was 110 +/- 10. Forty-three percent of the variance in MDI and PDI scores was explained by treatment factors, such as the treatment group, initial FT(4) concentration, FT(4)-A, and FT(4)-B. CONCLUSIONS: Our data suggest that optimal treatment includes achievement of euthyroidism before the third week of life by initiation of therapy before 13 days with a levothyroxine dose above 9.5 microg/kg/d and maintenance of FT(4) concentrations in the upper normal range during the first year. Thus treated, patients with CH can achieve normal psychomotor development at 10 to 30 months, irrespective of the severity of the disease.

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OBJECTIVE: To assess the effects of long-term growth hormone (GH) treatment for short stature on left ventricular (LV) dimensions and systemic blood pressure (BP) in girls with Turner's syndrome without clinically relevant cardiac abnormalities. STUDY DESIGN: LV dimensions measured by echocardiography and systemic BP were assessed before and during 7 years of GH treatment in 68 girls with Turner's syndrome participating in a randomized dose-response study. These previously untreated girls, age 2 to 11 years, were randomly assigned to 1 of 3 GH dosage groups: group A, 4 IU/m(2)/d; group B, first year 4 IU/m(2)/d, thereafter 6 IU/m(2)/d; group C, first year 4 IU/m(2)/d, second year 6 IU/m(2)/d, thereafter 8 IU/m(2)/d. After the first 4 years, girls >/=12 years of age began receiving 17beta-estradiol, 5 microg/kg body weight per day, for induction of puberty. RESULTS: At baseline the LV dimensions of almost every girl were within the normal range, and the mean SD scores were close to zero. During 7 years of GH treatment, the growth of the left ventricle was comparable to that of healthy girls. No signs of LV hypertrophy were found. Before the start of GH treatment, mean BP was within the normal range but significantly higher than in healthy control subjects. Diastolic BP and systolic BP were above the 90th percentile in 23% and 28% of the girls, respectively. After 7 years of treatment, these percentages were 14% and 36%, respectively (not significantly different from baseline). The SD score of the diastolic BP showed a small decrease after 7 years of treatment. The growth of the left ventricle and the development of BP were not different between the GH dosage groups. CONCLUSIONS: Long-term GH treatment, even at dosages up to 8 IU/m(2)/d, does not result in LV hypertrophy or hypertension in girls with Turner's syndrome. Continued observation into adulthood is recommended to monitor the further development of the relatively high BP and to ensure that GH treatment has no long-term negative effect on the heart.

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Thirty short, slowly growing children with normal plasma growth hormone response to standard provocation tests were randomly assigned to a group (n = 20) undergoing therapy with methionyl growth hormone, 2 IU/m2 subcutaneously once daily, (group 1) or a control group (n = 10, group 2). The mean (+/- SD) height velocity increment in group 1 was 3.0 +/- 1.9 cm/yr in the first year, compared with -0.2 +/- 0.7 cm/yr in group 2. Of the 18 children who completed the first year of treatment, 12 had a height velocity increment of more than 2 cm/yr and 11 of them continued treatment for a second year (group 1A). The remaining six children also reached height velocities greater than the mean for bone age, but because of a low height velocity increment they were termed nonresponders and their growth hormone dosage was increased to 4 IU/m2/day (group 1B). Of the 10 children in the control group, seven received authentic biosynthetic growth hormone in the second year of the study (group 2); the remaining three received no therapy (group 3). The mean height velocities (measured in centimeters per year) before and during the first and second years of therapy were 3.6, 7.6, and 6.1 in group 1A; 5.7, 6.9, and 7.3 in group 1B; 4.2, 4.0, and 6.7 in group 2; and 5.0, 4.9, and 5.2 in group 3. The effect of doubling the dosage was a further increase of 1.9 cm/yr. Bone age advance paralleled growth acceleration, resulting in an unchanged height standard deviation score for bone age and ambiguous results on final height prediction. Growth hormone therapy in such short children appears to be safe and efficacious in increasing growth velocity for 2 years, but its efficacy in terms of increasing final height is uncertain.

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