1.What is growth hormone deficiency?
Growth hormone deficiency is a condition in which the anterior pituitary gland does not secrete enough growth hormone to cause stunted growth and short stature in children. Primary growth hormone deficiency is mostly seen in boys, whose height and weight are normal at birth, but growth retardation appears after a few weeks, and gradually becomes obvious after 2-3 years old. The height is more than 2 standard deviations lower than normal children of the same age. The lack of secondary sexual characteristics and sexual organ dysplasia may appear with age. Secondary growth hormone deficiency can occur at any age, and in addition to the above symptoms, there are also signs and symptoms of the primary disease. Once the disease is diagnosed, the younger the age at which treatment is started, the better the results. At present, domestic recombinant human growth hormone has been widely used.
2.Clinical manifestations of growth hormone deficiency
A small number of primary growth hormone deficiency is hereditary and can be autosomal recessive, dominant or sex-linked recessive, with several members of the family suffering from the disease.
(1) Normal height and weight at birth, with a slowed growth rate of less than 4 cm per year after 3-6 months of age, and a height significantly lower than that of children of the same age at 2-3 years of age.
(2) Proportional dwarfism.
(3) Infantile facial appearance, subcutaneous fat abundance, and shrill voice.
(4) Delayed bone age.
(5) Delayed pubertal development.
(6) Normal intelligence.
(7) Growth hormone excitation test: growth hormone peak <5ng/ml for complete growth hormone deficiency, 5-10ng/ml for incomplete growth hormone deficiency.
(8) Insulin-like growth factor IGF-I and growth factor binding protein IGFBP3 are lower than normal.
(9)The cranial pterygoid saddle X-ray may reveal a small volume of the pterygoid saddle, and the cranial MRI may show a shrinking pituitary gland, displacement and disappearance of the posterior pituitary lobe and disappearance of the pituitary stalk.
(10) If there is insufficient secretion of thyroid hormone or adrenal sebaceous hormone, the corresponding clinical manifestations may appear.
3.Main diagnostic basis
(1) Short stature, height lags behind the third percentile or below of normal children of the same age and sex.
(2) Slow growth, growth rate <4cm/year.
(3)bone age more than 2 years behind the actual age.
(4) GH stimulation test shows partial or complete GH deficiency.
(5) Normal intelligence, proportional to age.
(6) Exclude the influence of other diseases.
4.Growth hormone stimulation test
The diagnosis of growth hormone deficiency relies on GH measurement, the normal human serum GH value is very low and pulsatile secretion, affected by various factors, so the random blood measurement of blood GH is not meaningful for diagnosis, but if the arbitrary blood GH level is significantly higher than normal (>10μg/L), GHD can be excluded, therefore, children suspected of GHD must make GH stimulation test to determine the function of pituitary secretion of GH.
The physiological test is a screening test and the drug test is a confirmatory test. It is generally considered that during the test, a peak GH value <10μg/L is considered as abnormal secretion function, a peak GH value <5μg/L is considered as no complete GH deficiency, and a peak GH value 5-10μg/L is considered as partial GH deficiency. The diagnosis of GHD can be confirmed only when the results of two or more drug stimulation tests are abnormal, because of the limitations of various GH stimulation tests, and generally arginine plus colistin or levodopa tests are chosen. In addition, if the lesion is located in the hypothalamus or pituitary gland, GHRH stimulation test is required.