Growth disorders in children

Growth disorders in children are primarily divided into growth retardation (short stature) and excessive growth. Knowledge of growth physiology and diagnosis of its abnormalities is a key component for fault detection.

Physiology of child growth
The human growth model is characteristic and is referred to as the sandwich because there is a period of steady growth (childhood; years 2 to 11) between the period of rapid postnatal growth and pubertal growth of life). This model is different from other biological species. Described as the ICP growth model by Swedish auxologist Karlberg:
 * I (infancy), infantile component of growth - from the 2nd half of intrauterine development to the 3rd to 4th year of life; IGF-I applies in particular;
 * C (childhood), the child component of growth - begins before the end of the 1st year of life and lasts until the end of physical growth; the dominant effect of growth hormone and the persistence of IGF-I;
 * P (puberty), pubertal growth component - puberty-induced additional growth phase; it accelerates to the age of highest growth rate, it slows down until the end of growth; influence of sex hormones.[1]

Diagnostics
The basis is an accurately measured body height stadiumiometer and a reconstruction of the anamnestic growth curvefrom previous data - this will allow us to retrospectively assess growth rate. We compare the current height with the parent height prediction, assess the stage of puberty (we estimate the future adult height of the child by projecting the current position of the child in the percentile graph on the right margin at the age of 18). Parental prediction: This reveals a possible "benign" familial growth retardation.
 * for boys: (father's height + mother's height + 13)/2;
 * for girls: (father 's height + mother' s height - 13)/2.

It is best to use a tiered diagnostic algorithm. The next step is routine laboratory tests (blood count, inflammatory parameters) supplemented by an X-ray of the hand to assess bone age. Subsequently, we purposefully direct our efforts:
 * high sedimentation may indicate Crohn's disease;
 * increased creatinine reveals chronic renal failure;
 * a disorder of calcium-phosphate metabolism indicates the possibility of vitamin D resistant rickets or  pseudohypoparathyroidism;
 * metabolic acidosis raises suspicion of renal tubular acidosis;
 * antiendomysial Ig as signs celiac disease;
 * TSH, fT4.

Growth hormone secretion testing is usually indicated in decreased IGF-1, which correlates with mean growth hormone levels. It is performed by a stimulation test in which it should be washed out - different variants with different substances (clonidine, pyridostigmine). The insulin hypoglycemia stimulation test is reliable but risky. The final step in children with growth hormone deficiency is MRI.[2]

Genetic testing
In the case of short stature without a known organic cause, it is recommended to supplement the genetic examination. Especially in girls, it is necessary to rule out Turner's syndrome (the only manifestation of which may be a small increase in the prepubertal period). Karyotype examination can also be indicated in boys (to exclude rare 45, X / 46, XY mosaicism). In both sexes, a SHOX gene examination is then indicated to rule out idiopathic short stature associated with SHOX deficiency.

Growth retardation
By growth retardation we mean a child's height below the 3rd percentile for a given age or growth rate below the 25th percentile for a given age ( calculated from two measurements at least 6 months apart.)

Etiology
There are 4 main groups: They make up the largest part, about 80% - their height is small, but the growth rate is usually normal. It has two main forms: A common feature is the absence of a demonstrable medical condition associated with growth retardation. It is considered a variant of normal, special treatment.
 * Children small but healthy ("short-normal")
 * familially small stature ( familially small stature ,FSS);
 * constitutional growth retardation and puberty ( constitutional growth retardation and puberty , CDGA).

Children with endocrine disorder

This is a fraction of low-growth children (1-2%). Early differentiation is important because normal height can be achieved with early treatment. Their general condition is seriously disturbed, but the disorders are usually well treatable. Disorders include growth hormone deficiency, hypothyroidism or unknown diabetes mellitus.

Children with chronic systemic diseases

Most chronic conditions lead to growth retardation. The spectrum of diseases is wide - most of them offer an axis (IGF-I), or calcium phosphate metabolism or bone growth directly. Growth adjustment is usually dependent on the successful treatment of the basic treatment, the mechanism of influencing IGF is applied (production in the liver decreases during proteoenergetic malnutrition, hypoxia, acidosis…). Its production of growth hormone (whose secretion can be reduced even in psychosocial hardship). The effect of growth hormone treatment has been demonstrated in some diagnoses (especially in chronic renal insufficiency).

Children with primary skeletal growth disorder:

Completely normal levels of hormones, including IGF, are typical. Growth is mostly disproportionate - the classic defect is achondroplasia (or a milder variant of hypochondroplasia) - disruption due to FGFR-3, and other bone dysplasia. Also common in most chromosomal abnormalities - eg Turner syndrome.

Growth retardation therapy
In children with growth factor deficiency - substitution treatment, every night  s.c.  injections. Successful treatment has been demonstrated in Turner syndrome or, for example, chronic renal failure. Puberty also needs to be regulated in Turner syndrome.

Excessive growth
Body height above the 97th percentile for a given age, or growth rate above the 75th percentile for a given age, are less likely to be examined than insufficient growth, as the physiological variant of a taller figure is perceived as socially beneficial. Growth disorders associated with overgrowth are significantly less common.

Etiology and diagnostics

 * Physiological variants: familial growth, constitutional growth acceleration, and puberty.
 * True premature puberty - idiopathic or organically conditioned.
 * Premature pseudopuberty - adrenal tumor, gonadal tumor, congenital adrenal hyperplasia, testotoxicosis, McCune-Albright syndrome, ectopic production of gonadotropins (eg hepatoblastoma).
 * Endocrinopathy - thyrotoxicosis, acromegalogigantism.
 * With dysmorphic symptoms:
 * Marfan's syndrome - long slender limbs, arachnodactyly, scoliosis, aortic dissection…
 * Homocystinuria - marfanoid body habitus, mental retardation…
 * Cerebral gigantism - macrosomy at birth, prominent body, large arms and legs…
 * Klinefelter's syndrome - disproportionately long limbs (eunuchoid growth)…

Therapy
Sometimes parents of girls with a physiological "tall-normal" body variant come with a request for height reduction - theoretically this can be done with estrogen, but it is necessary to start inducing puberty before the age of 10, and the risk of tumors remains an issue. Similarly, testosterone can theoretically reduce adult height.

Source

 * BENEŠ, Jiří. Studijní materiály [online]. ©2007. [cit. 2009]. .

Literature

 * HRODEK, O a J VAVŘINEC, et al. Pediatrie. 1. vydání. Praha : Galén, 2002. 767 s. ISBN 80-7262-178-5.


 * ŠAŠINKA, M, et al. Pediatria, zv. I a II. 1. vydání. Košice : Satus, 1998. ISBN 80-967963-0-5.


 * LEBL, J, K. PROVAZNÍK a L. HEJCMANOVÁ, et al. Preklinická pediatrie. 1. vydání. Praha : Galén, 2003. 248 s. ISBN 80-7262-207-2.