Approach to a child with short stature

Approach to a child with short stature

Introduction:

• Short stature is not a disease; it is a term applied to a child who is 2SD (Standard Deviations) or more below the mean height for children of that sex and chronologic age (and ideally of the same racial-ethnic group). This translates into being below the 3rd percentile for height. [1]

• Growth failure denotes a slow growth rate regardless of stature.

• A single measurement of height is much less important in assessing growth than is the pattern of growth over a period of time.

• Our main goal in evaluation of short stature; is to distinguish pathological short stature from non-pathological.

Important points to be addressed in history:

• Size at birth & pattern of growth:

· Approximately 90 percent of term small for gestational age (SGA) infants without intrinsic fetal abnormalities display sufficient catch-up growth to attain a height above -2SDS (Standard Deviation Score) by the age of 2 years, whereas 10 percent remain short throughout childhood and adolescence. [2-4]

· Familial and constitutional short stature typically have normal birth size then decelerate in the first 2 years of life.

• Family history & parental height:

· Family history of short stature: for suspected familial short stature.

· Family history of delayed puberty: for constitutional short stature.

• Pregnancy problems:

· Maternal disease (pre-eclampsia, SLE… etc.)

· Intrauterine infections.

· Exposure to drugs, alcohol, smoking, radiation.

• Nutritional history: adequate caloric intake and drinking & eating habits (for under-nutrition).

• Age of puberty (for constitutional delay).

• History of chronic disease:

· Endocrine: uncontrolled Diabetes Mellitus. [5]

· GI: Celiac, inflammatory bowel disease.

· Renal: chronic kidney disease.

· Pulmonary: cystic fibrosis, asthma.

· Cardiac: congestive heart failure, left to right shunt.

· Immunodeficiency: opportunistic/recurrent infections.

• Symptoms of hypothyroidism (cold intolerance, weight gain …etc.)

· The most common manifestation of hypothyroidism in children is declining growth velocity, resulting in short stature. [6]

• Glucocorticoid therapy. [7]

• Visual symptoms, headache & menstrual irregularities: suspected pituitary tumors.

• Polyuria, polydipsia, vomiting, early morning nausea: for suspected CNS masses.

• Milestones delay: for GH deficiency.

• Psychological problems (emotional deprivation, social withdrawal…etc.): for Psychological short stature.

Physical exam:

• Growth parameters: Height, weight, head circumference & plot them on appropriate growth charts.

· N.B: one of the more common causes of apparent growth failure (and short stature) is mis-measurement or aberrant plotting of the data. [8]

· Ideally, measure each parent's height in the clinic for optimal calculation of the mid-parental target height, at 20 years of age:

§ Target height in cm for a girl = [mother's height in cm+(father's height in cm-13)]/2

§ Target height in cm for a boy = [(mother's height in cm+13)+father's height in cm]/2

§ For both girls and boys, 8.5 cm on either side of this calculated value (target height) represents the 3rd to 97th percentiles for anticipated adult height.

• Dysmorphic features:

· Down syndrome (depressed nasal bridge, low set ears, up slanting eyes...etc.)

· Turner syndrome (girl, webbed neck, micrognathia, increased carrying angle… etc.)

§ N.B: any girl with unexplained short stature should have chromosomal evaluation for turner syndrome.

· Prader-Willi syndrome (obesity, sleep apnea, recurrent respiratory infections…etc.)

• Calculate Growth velocity:

· Growth velocity is a rate of height gain (increase in linear growth) per unit time (2 readings at least 6 months apart); then plot it on appropriate chart.

· Normal values of growth velocity; infantile (30-35 cm in the first 2 years), childhood phase (5-7 cm/year; relatively constant), pubertal phase (8-14 cm/year)

• Calculate upper: lower segment ratio:

· The lower segment is the measurement from symphysis pubis to the floor.

· The upper segment = Total height – Lower segment.

· Normal values of US:LS ; normal term infant (1.7:1), a 1 year old (1.4:1), a 10 year old (1:1).

· Patients with short limb dwarfism usually have an US:LS ratio that remains above 1.3

• Measure arm span:

· Arm span is measured as the distance between the tips of the fingers when the patient holds both arms outstretched horizontally while standing against a solid surface.

· Arm span is essential when the diagnosis of Marfan or Klinefelter syndrome, short-limbed dwarfism, or other dysmorphic conditions is considered.

• Inspect the 4th metacarpal for pseudo-hypoparathyroidism.

• Visual field exam.

• Thyroid exam and signs of hypothyroidism.

• Central obesity & striae: for suspected Cushing's syndrome.

• Secondary sexual characteristics: for suspected precocious puberty.

· The hallmarks of precocious puberty are accelerated growth and advanced bone age, plus breast development in girls and penile enlargement and sexual hair growth in boys. [9]

• Truncal obesity and micropenis: for GH deficiency.

Clinical approach:

• 1st step in evaluation of short stature is taking appropriate history and doing proper physical examination as above.

• Plot the height of the child on appropriate growth chart to establish the diagnosis of short stature.

Approach to a child with short stature

• Look for any dysmorphic features:

· If present, proceed to chromosomal analysis and other investigation to diagnose the specific syndrome/disease.

• Calculate Growth velocity.

· If decreased; measure US:LS ratio.

§ If US:LS is normal (proportionate short stature), do weight: height ratio; which is increased / normal in endocrinopathy and decreased in malnutrition or other chronic disease.

§ US:LS ratio is high in skeletal dysplasias/Rickets and low in spinal spondylolysis.

· If increased and bone age* >> height age** > chronological age; precocious puberty is suspicious.

· If normal, assess bone age and height age.

§ Height age = bone age < chronological age occurs in constitutional short stature.

§ Height age < bone age = chronological age occurs in genetic (familial) short stature.

*Bone age: an estimate of the biologic age of a child based on an x-ray taken for non-dominant hand and wrist (epiphyseal center maturity).[10]

**Height age: the age that corresponds to the child's Height when plotted at the 50th percentile on a growth chart. [11]

References:

1. [Best Evidence] [Guideline] Cohen P, Rogol AD, Deal CL, et al. Consensus statement on the diagnosis and treatment of children with idiopathic short stature: a summary of the Growth Hormone Research Society, the Lawson Wilkins Pediatric Endocrine Society, and the European Society for Paediatric Endocrinology Workshop. J Clin Endocrinol Metab. Nov 2008; 93(11):4210 -7. [Medline].

2. Karlberg JP, Albertson-Wikland K, Kwan EY, et al. The timing of early postnatal catch-up growth in normal, full-term infants born short for gestational age. Horm Res 1997; 48 Suppl 1:17.

3. Karlberg JP, Albertson-Wikland K. Growth in full-term small-for-gestational-age infants: from birth to final height. Pediatr Res 1995; 38:733.

4. Paz I, Seidman DS, Danon YL, et al. Are children born small for gestational age at increased risk of short ststure? Am J Dis Child 1993; 147:337.

5. Current, diagnosis and treatment, p948,20e.

6. Ozer G, Yüksel B, Kozanoğlu M, et al. Growth and development of 280 hypothyroidic patients at diagnosis. Acta Paediatr Jpn 1995; 37:145.

7. Allen DB. Growth supperession by glucocorticoid therapy. Endocrinol Metab Clin North Am 1996; 25:699.

8. Rogol, AD, Lawton, EL.Body measurements. In:pediatric outpatient procedures, Lohr, JA(Ed), JB Lippincott, Philadelphia 1991.p.1.

9. Kaplan SL, Grumbach MM. Clinical review 14: Pathophysiology and treatment of sexual precocity. JClin Endocrinol Metab 1990; 71:785.

10. Clinical pediatric endocrinology by Charles Groves Darville Brook, Peter E. Clayton, Rosalind S. Brown.

11. Stedman's Medical Dictionary. Copyright Ⓒ 2006 Lippincott Williams & Wilkins.