Definition of short stature
Short stature is defined as individuals of the same race, sex and age who are less than 2 standard deviations (-2SD) of the mean height of the normal population or less than the 3rd percentile (-1.88SD) in similar life circumstances, some of which are normal physiological variants, and for proper diagnosis, appropriate clinical observations and laboratory tests must be performed in children with growth retardation.
Etiology
There are many factors leading to short stature, and many of them interact with each other, and the mechanism of short stature due to many diseases has not been clarified so far.
Diagnosis
A comprehensive examination of children with short stature is necessary to identify the cause and facilitate treatment.
I. Medical history
The following should be carefully investigated: the pregnancy of the child’s mother; the birth history of the child; the birth length and weight; the growth history; the parents’ youth development and the short stature in the family, etc.
Physical examination
In addition to the routine physical examination, the following items should be measured and recorded correctly.
① Current height and weight measurement values and percentile;
②The annual growth rate of height (at least 3 months of observation);
③Target height measured from the height of the parents;
④BMI value;
⑤ Sexual development staging.
III. Laboratory tests
Blood and urine tests and liver and kidney function tests should be routinely performed; blood gas and electrolyte analysis are recommended for suspected renal tubular toxicity; karyotype analysis is required for girls; to exclude subclinical hypothyroidism, thyroid hormone levels should be routinely tested.
Bone Age (BA) is a good indicator to assess the development of an organism. Bone age is the maturity of bone at each age, and is determined by observing the growth and development of each ossification center on ortho-X-rays of the left wrist, palm and finger bones. The most used methods at home and abroad are the G-P method (Greulich & Pyle) and the TW3 method (Tanner-Whitehouse), and the G-P method is mostly used in our clinic. Under normal circumstances, the difference between bone age and actual age should be between ±1 year, and being too far behind or too far ahead is considered abnormal.
3.Special examination
(1) Indications for special examination
(1) The height is lower than the normal reference value minus 2 SD (or lower than the 3rd percentile);
②Bone age below the actual age of 2 years or more;
③Height growth rate below the 25th percentile (according to bone age), i.e. <7CM/rh for children <2 years old;
(iv) Those with clinical symptoms of endocrine disorders or dysmorphic syndrome;
(5) Those who need pituitary function examination for other reasons.
(2) Growth hormone-insulin-like growth factor-1 axis (GH-IGF-1) function determination The physiological screening tests such as exercise and sleep that were used in the past are rarely used nowadays, and most of them are directly used for drug stimulation tests (see Table 2).
(3) Measurement of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) The serum concentrations of both increase with age and development, and are related to nutrition and other factors, so each laboratory should establish its own reference data.
(4) IGF-1 production test For children with suspected GH resistance (Laron syndrome), this test can be used to detect GH receptor function.
Method 1: rhGH was injected subcutaneously at 0.075-0.15U/(kg・d) every night for 1 week, and blood samples were collected once before and once on the 5th and 8th day after the injection to determine IGF-1;
Method 2: Subcutaneous rhGH was administered at 0.3 U/(kg・d) every night for 4 days, and blood samples were collected once before and once after the last injection for the determination of IGF-1.
(5) Testing of other endocrine hormones Depending on the clinical manifestations of the child, testing of other hormone choices of the child can be performed as needed
(6) Imaging of hypothalamus and pituitary gland MRI should be performed in children with short stature to exclude the possibility of congenital developmental abnormalities or tumors.
(7) Karyotype analysis Karyotype analysis should be performed in all children suspected of having chromosomal aberrations.