Short Stature

Height < 3rd centile or > 2 SDs below the median height for age and gender (<-2 SD) according to the population standard.

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Classification

1. Constitutional/familial
   • 2-3 SD
2. Pathological
   • < -3 SD

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Etiology

Physiological causes:

• Familial short-stature
• Constitutional short stature
  • History of delayed puberty and delayed height spurt usually present in one or both parents

Pathological causes:

• Undernutrition (M/C cause in India)
• Chronic systemic illness:
  • Cerebral palsy
  • Congenital heart disease, cystic fibrosis, asthma
  • Malabsorption (celiac disease, chronic liver disease)
  • AIDS, etc
• Endocrine causes:
  • Growth hormone deficiency/insensitivity
  • Hypothyroidism
  • Pseudohypothyroidism
  • Cushing syndrome
  • Precocious/delayed puberty
• Psychosocial dwarfism/Emotional-deprivation dwarfism/Maternal-deprivation dwarfism/Hyperphagic short stature,
  • Characterised by:
    • ↓ IGF-1 levels
    • Inadequate response of GH to stimulation
• Children born small for gestational age (SGA)
• Skeletal dysplasias:
  • Achondroplasia
  • Rickets
• Genetic syndromes:
  • Turner syndrome
  • Down syndrome

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Assessment

Accurate height measurement

• < 2 years: Supine length (infantometer)
• Older children: Standing height (stadiometer)

Assessment of height velocity

↓ Height velocity indicates pathological cause

• 1st year: 25 cm/yr
• 4-9 year (peripubertal children): 4-6 cm/yr
• Puberty: 10-12 cm/yr

Comparison with population

Comparison with child’s own genetic potential

• Mid-parental height (MPH)
  • Value plotted on growth chart at 18-20 yr age (adult equivalent)
  • Boys: [Mom + dad (cm)/2] + 6.5 cm
  • Girls: [Mom + dad (cm)/2] – 6.5 cm

Assessment of body proportion

• Upper segment (US):(LS) Lower segment ratio
  • Birth: 1.7
  • 3 years: 1.3
  • 6 years: 1.1
  • 10 years: 1
  • Adults: 0.9
• Arm span relative to height
  • Birth: 2.5
  • 11 years: Equal to height
  • Adult: <1 cm greater than height

Sexual Maturity Rating (SMR)

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Diagnosis

Level 1 (essential) investigations

• Complete hemogram + ESR
• Bone age
  • Delayed compared to chronological age
    • All pathological causes of short stature
  • Equal to chronological age
    • Familial short stature
  • Exceeds chronological age
    • Precocious puberty
• Urinalysis:
  • Microscopy, osmolality and pH
• Stool examination
  • For parasites, steatorrhea and occult blood
• Blood urea, creatinine, bicarbonate, pH, calcium, phosphate, alkaline phosphatase, fasting glucose, albumin and transaminases

Level 2 investigations

• Serum thyroxin, TSH
• Karyotype in girls (to rule out Turner syndrome)

Level 3 investigations

• Celiac serology:
  • Antiendomysial, anti-tissue transglutaminase antibodies
• Provocative growth hormone testing
• Serum insulin-like growth factor-1, and insulin-like growth factor binding protein-3 levels
• MRl brain (focussed on pituitary and hypothalamus)
  • For those with low peak growth hormone levels

Differential diagnosis

Feature	Constitutional growth delay	Familial short stature
Height	Short	Short
Height velocity	Normal	Normal
Family history	Delayed puberty	Delayed puberty
Bone age	Less than chronological age	Normal
Puberty	Delayed	Normal
Final height	Normal	Low but normal for target height

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Management

General measures:

• Parents counselling
• Dietary management:
  • Balanced diet
  • Dietary rehabilitation

Specific treatments:

• Bone dysplasias:
  • Limb-lengthening procedures
• Hypothyroidism:
  • Levothyroxine replacement
• Growth-hormone deficiency:
  • GH therapy