Short stature is defined as height that is two standard deviations below the mean height for age and sex (less than the 3rd percentile) or more than two standard deviations below the mid-parental height. The child's rate of growth is important. A downward growth trend suggests a slowdown in growth and possibly a growth problem. A growth velocity disorder is defined as an abnormally slow growth rate, which may manifest as height deceleration across two major percentile lines on the growth chart. The causes of short stature can be divided into three broad categories:
- Familial short stature.
- Constitutional delay of growth and development.
- Chronic disease, including malnutrition and genetic disorders.
In some cases, short stature or slow growth is the initial sign of a serious underlying disease in an otherwise healthy child.
Causes of short stature
Endocrine diseases are rare causes of short stature. Most children with short stature will have constitutional delay of growth and puberty (CDGP) or familial short stature. Causes include:
- Normal variant:
- Familial short stature, constitutional short stature.
- Psychosocial deprivation, including hyperphagic short stature syndrome.
- Intrauterine growth restriction:
- Chronic disease:
- Skeletal dysplasias:
- Chondrodysplasias, osteogenesis imperfecta, rickets.
- Chromosomal abnormalities:
- Turner's syndrome, trisomy syndromes.
Obtaining the family history of growth patterns and direct measurement of the parents is crucial to determine the genetic potential for growth in the child. Short stature can also be the sign of a wide variety of pathological conditions or inherited disorders when it results from growth failure or premature closure of the epiphysial growth plates.
- A comprehensive history starting in the prenatal and perinatal periods should be obtained. Emphases of the history include maternal health and habits during pregnancy, the duration of gestation, birthweight and length, and growth pattern (centile charts if available).
- General nutrition, including problems with feeding, appetite, food science, special diets or any other indication of inadequate nutrition.
- Consider any chronic disease and medication. Careful review of physical symptoms suggesting underlying chronic disease, such as breathlessness, diarrhoea.
- Consider any signs of developmental delay or any features that may indicate an underlying syndrome such as Turner's syndrome.
- Any indication of possible child abuse, including interaction of the child with the parent.
A thorough examination is essential to establish accurate height and weight and any indication of a possible underlying cause for short stature.
- Accurate measurement of height (using a calibrated stadiometer) and weight. Sitting as well as standing height are important in order to consider asymmetry and skeletal disproportion, eg achondroplasia.
- A thorough physical examination helps differentiate abnormal growth patterns from normal variants and identifies specific dysmorphic features of genetic syndromes.
- Growth hormone deficiency from hypopituitarism: other features of pituitary hormone deficiency, eg hypogonadism, and possible features of a pituitary tumour, eg papilloedema and visual field defections.
- Consider any indications of other possible underlying causes, eg Cushing's syndrome, chronic kidney disease, hypothyroidism or fetal alcohol syndrome.
- Features of Turner's syndrome in girls.
- Skeletal causes, eg rickets (craniotabes, bulbous wrists and bowing of the extremities), achondroplasia.
Calculate expected final height
- The mid-parental height provides an estimation of the expected final height. If a child's height lies within the target centile range, then their height is normal with regard to their genetic potential.
- A calibrated stadiometer should be used for measuring standing height and the heights of the parents should be accurately measured rather than rely on reported heights. The mid-parental height is unreliable if the parents' heights are very different.
- In a boy:
- Mid-parental height (cm) = (Father's height + (Mother's height + 14)) divided by 2.
- Target centile range: ± 10 cm around the mid-parental height.
- In a girl:
- Mid-parental height (cm) = ((Father's height - 14) + Mother's height) divided by 2.
- Target centile range: ± 8.5 cm around the mid-parental height.
Investigations are indicated to confirm or exclude possible underlying causes based on the clinical assessment.
- Initial tests:
- FBC: anaemia blood dyscrasia, and infections.
- Renal function tests and electrolytes: renal disease and electrolyte abnormalities, eg Bartter's syndrome, diabetes insipidus and other renal and metabolic disorders.
- LFTs and TFTs.
- Urinalysis and urine pH level: renal tubular acidosis.
- ESR and CRP: chronic inflammatory conditions.
- Karyotyping (particularly considering Turner's syndrome) should be performed in all girls with short stature.
- Specific tests for suspected underlying or associated diseases, eg coeliac disease, Cushing's disease, cystic fibrosis, growth hormone deficiency, hypothyroidism, vitamin D deficiency.
- Bone age:
- Bone age can help to predict the final adult height by estimating skeletal maturation from an assessment of the ossification of the epiphyseal centers.
- The most widely used method is based on comparing a frontal radiograph of the left hand and wrist with standards from the Greulich-Pyle atlas.
- Overemphasis of bone age evaluation can be misleading if not used in the proper settings. The predictions do not apply to children with endocrine or bone pathologies affecting growth.
- Bone age is considered delayed if it is two standard deviations below the chronological age.
- Bone age is usually normal for age in children with familial short stature. In children with constitutional delay of growth and puberty (CDGP) the bone age corresponds with height age and is delayed (up to two standard deviations). In children with pathological short stature, the bone age is severely delayed (more than two standard deviations).
- Dental age: can provide an indirect assessment of skeletal age. The eruption of primary and secondary teeth may be delayed for up to 1.3 years in children with growth hormone deficiency, up to 1.5 years in children with constitutional delay of growth and puberty, and more than two years in children with severe hypothyroidism.
Indications for referral include:
- Height: height fails to progress along the appropriate centile curve.
- Growth velocity: decreased growth velocity for age.
- Genetic potential: projected height varies from mid-parental height by more than 5 cm (2 in).
- Multiple syndromic or dysmorphic features: abnormal facies, midline defects, body disproportions.
- Bone age: delayed by more than two standard deviations.
Management of any underlying cause.
- Growth hormone of human origin (somatotrophin) has been replaced by a growth hormone of human sequence, somatropin, which is produced using recombinant DNA technology.
- The National Institute for Health and Clinical Excellence (NICE) recommends that somatropin be used for the treatment of growth failure for children with growth failure who:
- Treatment should be discontinued if:
- Growth velocity increases by less than 50% from baseline in the first year of treatment.
- Final height is approached and growth velocity is less than 2 cm total growth in one year.
- Adherence is poor and cannot be improved.
- Final height is attained.
Growth hormone therapy in children with idiopathic short stature seems to be effective in partially reducing the deficit in height as adults, although the magnitude of effectiveness is on average less than that achieved in other conditions for which growth hormone is licensed. Treated individuals remain relatively short when compared with peers of normal stature. Mecasermin, a recombinant human insulin-like growth factor-I (rhIGF-I), is licensed to treat growth failure in children and adolescents with severe primary insulin-like growth factor-I deficiency.
Further reading & references
- Nwosu BU, Lee MM; Evaluation of short and tall stature in children. Am Fam Physician. 2008 Sep 1;78(5):597-604.
- Ferry Jr et al; Short Stature, Medscape, Apr 2010
- Spadoni GL, Cianfarani S; Bone age assessment in the workup of children with endocrine disorders. Horm Res Paediatr. 2010;73(1):2-5. Epub 2010 Jan 15.
- Human growth hormone (somatropin) for the treatment of growth failure in children, NICE Technology Appraisal (May 2010)
- Deodati A, Cianfarani S; Impact of growth hormone therapy on adult height of children with idiopathic BMJ. 2011 Mar 11;342:c7157. doi: 10.1136/bmj.c7157.
- Bryant J, Baxter L, Cave CB, et al; Recombinant growth hormone for idiopathic short stature in children and Cochrane Database Syst Rev. 2007 Jul 18;(3):CD004440.
- British National Formulary; 62nd Edition (Sep 2011) British Medical Association and Royal Pharmaceutical Society of Great Britain, London
|Original Author: Dr Colin Tidy||Current Version: Dr Colin Tidy|
|Last Checked: 22/06/2011||Document ID: 13651 Version: 1||© EMIS|
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