Are they really? Plot height and weight, and check figures if in doubt!

Investigate if:

• More than 2 standard deviations below mean worthy of investigation,
• more than 2 standard deviations below mean parental height.
• Height velocity less than 5cm per year

Is there evidence of chronic disease? Needs full history and examination, including urine dip. Common things would be renal failure, coeliac disease, IBD, hypothyroidism. Endocrine causes tend to produce relatively heavy children, other chronic diseases tend to produce relatively slight children.

Are they dysmorphic? Main syndromes to look out for:

• Turners – besides short stature, webbed neck, characteristic facies, short metacarpals, broad chest with widely spaced nipples, hyperconvex fingernails and toenails (but can be missed); decreased growth velocity and delayed puberty
• Short limbs – SHOX mutations eg Leri-Weill dyschrondeostosis but milder variants. Classically mesomelia (short proximal bones) and Madelung deformity (wrist) but these may only become obvious in later childhood.
• Achondroplasia or hypochondroplasia (FGFR3 (Fibroblast Growth Factor Receptor 3) mutations)

Bone age will be delayed in all except familial and idiopathic. Progressively falls behind in endocrine disorders.

Causes

Constitutional delay – good weight at birth, then “catch down” growth, dropping through centiles in infancy. Growth velocity is then normal, but with delayed bone age and delayed puberty.

Small for gestational age babies tend to catch up in first few years of life with their genetic potential, but can take up 4 years or more. 10% however remain small (more than 2 SDs below MPH) through life. Consider other causes if no catch up in first 6 months of life or still small at 2 years.

Growth hormone deficiency – can be congenital or acquired (head injury, meningitis etc). Early growth tends to be normal (growth hormone doesn’t contribute much in first few years of life). Look for microphallus and midline facial abnormalities.

Investigations

• Karyotype if dysmorphic or if girl
• TFTs
• IGF1 – screening test for Growth hormone problems, but may need GH stimulation testing as limited reference ranges in under 2s
• U&Es, LFTs, CRP/ESR
• Urinalysis
• Bone age