LHRH analogue and growth hormone did not improve the final height of a patient with juvenile hypothyroidism accompanied by precocious puberty

Evaluation of catch-up growth in severe pediatric Hashimoto's hypothyroidism

BACKGROUND

We aimed to evaluate catch-up growth in children with severe Hashimoto's hypothyroidism (HH) after thyroid hormone replacement therapy (HRT).

METHODS

A multicenter retrospective study was conducted including children referred for growth slowdown that led to the diagnosis of HH between 1998 and 2017.

RESULTS

A total of 29 patients were included, with a median age of 9.7 years (13-172 months). Median height at diagnosis was -2.7 [-4.6; -0.1] standard deviation score (SDS), with a height loss of 2.5 [0.7; 5.4] SDS compared to height before growth deflection (p<0.0001). At diagnosis, the median TSH level was 819.5 mIU/L [100; 1844], the median FT4 level was 0 pmol/L [undetectable; 5.4], and the median anti-thyroperoxidase antibody level was 1601 UI/L [47; 25,500]. In the 20 patients treated only with HRT, there were significant differences between height at diagnosis and height at 1 year (n = 19, p<0.0001), 2 years (n = 13, p = 0.0005), 3 years (n = 9, p = 0.0039), 4 years (n = 10, p = 0.0078), and 5 years (n = 10, p = 0.0018) of treatment but not in the case of final height (n = 6, p = 0.0625). Median final height was -1.4 [-2.7; 1,5] SDS (n = 6), with a significant difference between height loss at diagnosis and total catch-up growth (p = 0.003). The other nine patients were also given growth hormone (GH). They were smaller at diagnosis (p = 0.01); however, there was no difference in final height between those two groups (p = 0.68).

CONCLUSION

Severe HH can lead to a major height deficit, and catch-up growth seems to be insufficient after treatment with HRT alone. In the most severe cases, administration of GH may enhance this catch-up.

Gonadotropin-releasing hormone analog therapy for central precocious puberty and other childhood disorders affecting growth and puberty

Gonadotropin-releasing hormone (GnRH) analog therapy relies primarily on the ability of these compounds to bind to and modulate GnRH-receptor activity. GnRH analogs have been used in pediatric patients where endogenous gonadotropin release is undesirable or potentially harmful, such as in: (i) patients with central precocious puberty (CPP); (ii) healthy short children where pubertal delay would provide an opportunity to supplement pre-pubertal linear growth; and (iii) children with malignancies and other disorders where treatment requires the use of gonadotoxic compounds. In the first two groups of patients, GnRH agonists may be used alone or in conjunction with somatropin (growth hormone [GH]) to prevent early skeletal maturation and increase the subsequent adult height, while in the latter case, GnRH agonists are used alone or in conjunction with GnRH antagonists in an attempt to preserve gonadal function.In children and adolescents with CPP, timely use of GnRH agonists alone can result in an adult height within the genetic potential of the individual (target height); however, minimal height is gained when GnRH agonist therapy is commenced after a marked advancement of skeletal age. This provides the rationale for combined therapy with GnRH agonists and somatropin in such patients, and studies have shown improved growth with this approach compared with GnRH agonists alone. Combination therapy with GnRH agonists and somatropin has also been shown to increase adult heights to a greater extent than GnRH agonists alone in pediatric patients with concomitant CPP and GH deficiency, those with idiopathic short stature, and those born small for gestational age; however, such combination therapy has shown no increased benefit over somatropin alone in pediatric patients with GH deficiency. Limited results in children and adolescents with congenital adrenal hyperplasia and chronic primary hypothyroidism have also shown increased growth rates, while no growth benefit was seen in pediatric renal transplant recipients.GnRH analogs also have potential as gonadoprotective agents; studies of GnRH agonists used alone and in combination with GnRH antagonists in women undergoing cytotoxic therapy have shown increased preservation of reproductive potential in patients who were receiving GnRH analog therapy versus those who were not.The adverse effects of GnRH analogs mainly consist of menopausal-like complaints. Increases in bodyweight and body mass index in children receiving GnRH agonist therapy have been shown; however, these increases do not persist after discontinuation of therapy. Adult bone mineral density and fertility are also not adversely affected by childhood GnRH agonist therapy.GnRH analog therapy appears to be both well tolerated and effective in pediatric patients, as it allows the preservation or improvement of adult height, and shows no longstanding negative effects on body composition, bone density, reproductive function, or endocrine physiology. These agents may also be useful for preservation of gonadal function in children and adolescents undergoing cytotoxic therapy.

Does clinical management impact height potential in children with severe acquired hypothyroidism?

BACKGROUND

Severe acquired hypothyroidism often results in significant height deficit due to rapid bone age advancement following treatment. Whether gradual correction of hypothyroidism and/or adjunctive growth-promoting therapies (GPTs) augment final adult height (FAH) is controversial.

OBJECTIVE

To investigate time to euthyroidism, pace of bone age advancement (deltaBA/deltaCA), and impact of GPTs on FAH.

METHODS AND PATIENTS

Retrospective review of 21 children (10.1 +/- 3.0 years) with profound hypothyroidism.

RESULTS

Baseline bone age standard deviation score (SDS) was -4.1 +/- 1.8, whereas height SDS was -3.0 +/- 1.1. Average time to euthyroidism was 9.7 months (2.3-33.7 months). Average deltaBA/deltaCA was 2.3 +/- 0.9. Six of 13 patients at FAH received GPTs. No correlation was found between time to euthyroidism and rate of skeletal maturation. No difference in height outcome was seen between those who received GPTs and those who did not.

CONCLUSIONS

Neither time to euthyroidism nor use of GPTs significantly affected height potential in our patients.

Growth hormone therapy

Since 1958 growth hormone (GH) has been used as substitution treatment for children with GH deficiency. At present, it is clear that a dose of 0.23 mg/kg/week can lead to a final height close to target height, but in view of the wide inter-individual variation, alternative regimens based on invidualizing the dosage with the help of prediction models are being investigated. The best strategy during puberty (increase the dosage, delay puberty) is still uncertain. The value of GH in idiopathic short stature is still heavily debated, although the average final height gain on 0.33 mg/kg/week is 5-7 cm. GH is efficacious in short stature due to chronic renal failure and Prader-Willi syndrome. In other conditions insufficient data are available. There are few side-effects.