Approach to the Short Child

Background

Short stature in a child is defined as a child 2 or more standard deviations below the mean height for children of that gender and chronological age. The height growth pattern over a period of time is more important than a single measurement at one point in time. A growth pattern is abnormal if it shows slowed growth that deviates from a previous pattern or percentile (ie. crosses percentile lines on a linear growth curve).

A child’s growth is important because it is a strong indicator of his or her health. Short stature in a child must be fully investigated to distinguish between a normal variation and an underlying pathological condition.

Basic anatomy / physiology

Height growth is a continuous, non-linear process with three phases: infantile, childhood, and pubertal. In the first two years of life, or infantile phase, growth is rapid, but decelerates. During this time, intrauterine growth is offset as infants grow towards their genetic potential and may cross percentile lines. Total growth during this period is approximately 30 to 35 cm. During the childhood phase, growth is at a relatively constant velocity at 5 to 7 cm per year, often with a slight slowing in late childhood. Finally, in the pubertal phase, there is a growth spurt of 8 to 14 cm per year, as a result of increasing growth hormone and gonadal steroid hormone secretion.

A child has a final growth potential estimated using the mid-parental height, adjusted for the child’s gender. For girls, 13 cm is subtracted from her father’s height, which is then averaged with her mother’s height. For boys, 13 cm is added to his mother’s height, which is then averaged with his father’s height. A range 8.5 cm above or below this predicted height is considered within the 3rd to 97th percentile.

Girls: (Dad’s height + Mom’s height – 13cm)/2
Boys: (Dad’s height + Mom’s height + 13cm)/2

Normal variations of slowed growth include constitutional delay and familial or genetic factors.

Pathological conditions resulting in short stature include malnutrition or malabsorption, chronic diseases, skeletal or bone diseases, and endocrinopathies.

Presentation (and Differential Diagnosis)

There are 2 sub-classifications of short stature due to normal variation:

Familial Short Stature:

Short parents
Normal birth history and gestational weight
Short stature with:
Normal linear growth velocity for age
Bone age consistent with chronological age
Normal age for onset of puberty
Absence of physical or psychological disease

Constitutional Short Stature:

Delayed growth in one parent but average final stature
Normal birth history and growth for first few months

Short stature with:

Period of severe growth deceleration lasting 1-3 yrs and may begin at less than 2 years
Bone age lags chronological age
Delayed onset of puberty
Absence of physical or psychological disease
Final height consistent with mid-parental height

There are 4 patterns of short stature due to pathological conditions:

Increased Weight/Height ratio

Causes: Endocrinopathies
- Hypothyroidism
- Cushing’s syndrome
- Growth hormone deficiency
- Normal or decreased Weight/Height ratio
Causes: Inadequate calories
- Malnutrition
- Malabsorption (ex. due to Celiac Disease)
- Chronic Disease (ex. renal, cardiac, hematological)

Disproportionate weight for height

Causes:
- Skeletal dysplasias
- Metabolic bone disease
- Spinal disorders

Associated with dysmorphic features

Causes: Chromosomal abnormalities or syndromes
- Chromosomal: Down Syndrome, Turner’s Syndrome
- Non-chromosomal: Russell-Silver, Noonan syndrome
- Maternal exposures: Alcohol, smoking and other toxins

Question to Ask

Historical Investigation

Family History:

Include parents’ and siblings’ heights, age of puberty, medical problems, and history of consanguinity or congenital anomalies

Birth History:

Ask about maternal problems in pregnancy, complications with pregnancy or delivery, birth weight/length, and postnatal problems

Developmental History:

Investigate developmental milestones, age of tooth eruption, school performance

Diet and Nutrition History:

Check for sufficient calories, calcium, protein, and vitamins

Previous Medical History:

Include ear and urinary tract infections, poor appetite, diarrhea, trauma, surgery, or hospitalizations

Medication History:

Ask about usage of methylphenidate or other such stimulants, antidepressants, or anticonvulsants

Social History:

Check for factors that many influence normal growth, including sleep, exercise, and psychosocial factors such as a sense of security and of being loved

Investigations

Physical Examination

General examination – weight and height measurement and plot on the appropriate growth chart; body proportions – arm span, upper-to-lower body ratio, head circumference
General systemic examination including lungs, heart, abdomen, neurologic systems
Head and neck – for maturation (acne, facial hair), goiter
Dysmorphic features – palate, ear placement, size / shape of hands and feet
Hands – palmar creases, clinodactaly
Chest – widely spaced nipples, pectus excavatum or carinatum, breast development
Genitourinary – accurate Tanner staging

Anthropometry

Growth charts are very helpful for assessing growth velocity, including weight and height, and comparison to the mid-parental height.

Is growth truly delayed? Use mid-parental height growth potential prediction and determine appropriate normal range
When did growth delay begin?
- Intrauterine growth restriction (IUGR) vs. Birth related causes vs. postnatal causes
Is height growth chart normal?
- Less than Age 2: shifts across lines are normal
- Age 2-13: shifts across 2 growth chart lines are abnormal
Is Weight for Height normal?
- Short and obese: hormone deficiency, syndrome
- Tall and obese: exogenous obesity
- Short and thin: malnutrition, malabsorption, systemic disease, constitutional delay
Indicators of collagen bone disease:
- Abnormal arm span
- Abnormal upper to lower body ratio
- Disproportionate shortness

Radiology

Bone Age determination. Skeletal or bone age is usually determined by assessing the radiographic appearance of the bones in the hand and wrist and compared to standards. Bone age provides a more accurate assessment of projected height than dose chronological age.

Laboratory investigations

Urinalysis, CBC, ESR, LFT, serum calcium, serum iron, serum phosphorus, alkaline phosphatase

Specific indications:

To assess for Gluten Sensitive Enteropathy (celiac disease): tissue transglutaminase titres (TTG)
To assess for Cystic Fibrosis: Sweat Chloride
To assess for Growth Hormone deficiency: IGF-1, IGF-1 binding protein 3
To assess for Hypothyroidism: Thyroid stimulating hormone (TSH), Free T4
To assess for chromosomal abnormalities: Karyotype

Conclusions:

Short stature is common and is defined as height less than 2 standard deviations below the mean for children of the same sex and chronological age. There are many variations of growth and accurate serial measurements of a child’s weight and height to determine growth velocity are crucial to diagnosing the underlying cause of the child’s short stature.

Appendix

IUGR:

Causes include genetic / chromosomal abnormality, transplacental infectious disease, malnutrition, hypoxia, toxins (alcohol, nicotine, recreational drugs), medications

Birth related causes of growth delay:

Causes include birth asphyxia, birth trauma, hypoglycemia, prolonged neonatal jaundice, panhypopituitarism

Postnatal causes of growth delay:

Causes include child neglect, child abuse, insufficient caloric intake (ex. choanal atresia, cleft palate), defects in food assimilation (ex Celiac Disease, Liver disease, allergies), excessive loss of ingested calories (ex. chronic diarrhea, gastroesophageal reflux), increased energy requirements (malignancy, heart disease, renal disease, hyperthyroidism)