Growth charts

Reading a growth chart

A single point on a chart says almost nothing. The trajectory says everything
- Crossing centile lines downward = pathology until proven otherwise
- Tracking along the 3rd centile with normal velocity = usually normal

WHO growth standards 0-2 years (breastfed reference population)
CDC 2000 charts 2-18 years
Condition-specific charts: Down syndrome, Turner syndrome, preterm (corrected age until 2 years)

Height (supine length <2y), weight, head circumference (<3y), BMI
Growth velocity - needs >=6 months, ideally 12, between accurate measurements
Mid-parental height (target height)
- Boys: (mother + father + 13 cm) / 2
- Girls: (mother + father - 13 cm) / 2
- Target range = +/- 8-10 cm
Upper:lower segment ratio and arm span - separates proportionate from disproportionate short stature
Bone age (left hand and wrist X-ray) - compares skeletal to chronological maturity

By definition 2.3% of children are below the 2nd centile - most are normal
Constitutional delay: M>F, commonest cause of referral for short stature and delayed puberty in boys
GH deficiency: ~1 in 4,000-10,000

Phases of growth (Karlberg ICP model) - each has its own drivers

This is why the age at which growth failed points to the cause
Sex steroids drive the pubertal growth spurt AND fuse the epiphyses - precocious puberty causes a tall child and a short adult

Normal variants (bone age is the discriminator)

Familial short stature - short parents, bone age = chronological age, normal velocity, short adult
Constitutional delay of growth and puberty - bone age delayed, positive family history of late puberty, normal final adult height

Systemic disease - often the whole answer

Coeliac disease, inflammatory bowel disease (may be occult - growth failure can precede GI symptoms)
Occult renal disease/renal tubular acidosis, chronic anaemia, cystic fibrosis, congenital heart disease
Malnutrition

Endocrine - classically short AND overweight, with a delayed bone age

Genetic / skeletal

Turner syndrome (45,X) - check a karyotype in ANY short girl, even without stigmata
Noonan, Prader-Willi, Silver-Russell, SHOX deficiency
Skeletal dysplasia (achondroplasia - disproportionate, abnormal U:L ratio)
Small for gestational age without catch-up by 2 years

Psychosocial deprivation - growth resumes on removal from the environment; the diagnostic test is a change of address

Normal variant / familial tall stature - commonest
Klinefelter (47,XXY) - tall, reduced upper:lower segment ratio (long legs), small firm testes, gynaecomastia, learning difficulty, infertility
Marfan syndrome - arachnodactyly, thin extremities, arm span > height, reduced U:L ratio, aortic root dilatation, upward lens subluxation, kyphoscoliosis, high-arched palate
Homocystinuria - autosomal recessive (cystathionine beta-synthase); marfanoid habitus but downward lens subluxation, thrombosis, intellectual disability if untreated
- Homocystinuria vs Marfan is a classic pairing - the lens direction, the thromboembolism, and the inheritance separate them
Precocious puberty, hyperthyroidism, GH excess (gigantism), Beckwith-Wiedemann, Sotos, XYY, obesity (tall child, normal adult height)

First line: FBE, ESR/CRP, UEC, LFT, calcium/phosphate, coeliac serology (with total IgA), TFT, urinalysis, karyotype in every girl
Bone age X-ray left hand/wrist
IGF-1 +/- IGFBP-3 as GH screen (random GH is useless - GH is pulsatile)
GH provocation testing only after excluding systemic disease and hypothyroidism
MRI pituitary if GH deficiency confirmed or multiple pituitary hormone deficiency

Coeliac -> gluten-free diet; IBD -> disease control and minimise steroid
Hypothyroidism -> levothyroxine (caution: rapid catch-up can cause slipped capital femoral epiphysis and pseudotumour cerebri)
Constitutional delay -> reassurance + growth charting; short course of low-dose testosterone (boys) if distress is significant

GH deficiency
Turner syndrome
Prader-Willi syndrome
Chronic renal insufficiency
SHOX deficiency
Short stature/slow growth meeting height and velocity criteria (strict auxological criteria, assessed by a paediatric endocrinologist)
GH is not funded for idiopathic short stature on height alone

Height every 3-6 months, IGF-1, TFT, glucose
Watch for: benign intracranial hypertension, slipped capital femoral epiphysis, scoliosis progression, impaired glucose tolerance
Stop when growth velocity <2 cm/year or epiphyses fused

Turner syndrome - short stature, ovarian failure, coarctation/bicuspid aortic valve, webbed neck, renal anomaly
Klinefelter - tall stature, hypogonadism, gynaecomastia
Prader-Willi - hypotonia, hyperphagia, obesity, hypogonadism, short stature
Noonan - short stature, pulmonary stenosis, webbed neck, normal karyotype (RASopathy)
Coeliac disease, inflammatory bowel disease, cystic fibrosis, chronic kidney disease
Cranial irradiation for childhood cancer -> GH deficiency first, then other axes
Septo-optic dysplasia - optic nerve hypoplasia + absent septum pellucidum + hypopituitarism

Constitutional delay: normal adult height, reached late
Untreated GH deficiency: severe short stature, plus adult metabolic phenotype (central adiposity, dyslipidaemia, reduced BMD and quality of life)
Turner syndrome untreated: adult height ~20 cm below target; GH plus oestrogen improves this
Coeliac and IBD: catch-up growth occurs only if treated before epiphyseal fusion - the therapeutic window closes
Once epiphyses fuse, no intervention adds height - which is why a delayed diagnosis of a treatable cause is the real harm

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