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[Somatotropin secretion during sleep in 60 cases of growth retardation in children]
Insights
Nocturnal growth hormone (GH) secretion analysis in children with growth retardation helps differentiate true partial deficiencies from false ones. Sleep polygraphy provides valuable insights beyond standard stimulation tests.
Area of Science:
- Pediatric Endocrinology
- Sleep Medicine
- Growth Hormone Research
Background:
- Growth retardation in children necessitates accurate assessment of growth hormone (GH) secretion.
- Pharmacologic stimulation tests are standard but may not fully capture dynamic GH release patterns.
- Nocturnal GH secretion patterns during sleep offer a complementary diagnostic approach.
Purpose of the Study:
- To evaluate nocturnal somatotropic secretion in children with growth retardation using sleep polygraphy.
- To compare sleep-derived GH secretion data with pharmacologic stimulation test results.
- To differentiate true partial GH deficiency from other causes of growth failure.
Main Methods:
- Sixty children (1-18 years) with growth retardation (≥ -2SD) underwent polysomnography.
- Growth hormone (GH) secretion analyzed by peak value, number of peaks >5 ng/ml, and integrated concentration.
- Children categorized into four groups based on pharmacologic stimulation test responses.
Main Results:
- Sleep secretion and pharmacologic tests showed concordance in normal and complete GH deficiency groups.
- Sleep secretion analysis distinguished true partial GH deficiencies from "false partial deficiencies" or abnormal responders.
- Correlation analysis revealed GH peaks occurred across various sleep stages and sleep cycles, not exclusively during stage IV or the first cycle.
Conclusions:
- Nocturnal GH secretion assessment via sleep polygraphy is crucial for accurately diagnosing partial GH deficiency in children.
- Sleep studies offer a more nuanced understanding of GH secretion dynamics compared to stimulation tests alone.
- The relationship between GH peaks, specific sleep stages (like stage IV), and sleep cycles is not absolute, highlighting the complexity of GH regulation during sleep.
Abstract:
A study of nocturnal somatotropic secretion with sleep polygraphic recording was performed in 60 children, aged 1 to 18 years and presenting with growth retardation greater than or equal to -2SD. GH secretion was analysed according to the peak value, the number of peaks greater than 5 ng/ml and the integrated concentration (surface under the curve divided by the duration of the test). The children were studied in four groups according to the responses to pharmacologic stimulation tests: a normal group (n = 7), a group with complete somatotropic deficiency (n = 4), a group with partial somatotropic deficiency (n = 39) and a group with dissociated responses (n = 12). Results are concordant between sleep secretion and pharmacologic tests in the first two groups. On the contrary, in the two last, the study of the sleep secretion allows to differentiate children with hyposecretion ("true partial deficiencies") from children with normal secretion ("false partial deficiencies") or abnormal responders). In other respects, correlations between LH maximum peak and stages of sleep are analysed. The maximum peak was observed in only 33.9% of cases during stage IV, 21.5% of cases during stages I, II, III, in 19.6% of cases during wakefulness and in 25% of cases during paradoxical stage. The maximum peak was observed in only 48% of cases during the first cycle of sleep and in 52% of cases during the other cycles. These results show that the correlation between maximum peak, stage IV and first cycle of sleep is not absolute.