Growth Hormone Deficiency

Growth hormone deficiency (GHD) is inadequate GH secretion, causing short stature in children and metabolic changes in adults.

• Childhood: congenital (idiopathic, PROP1, POU1F1, GH1 mutations, septo-optic dysplasia) or acquired (craniopharyngioma, cranial irradiation, trauma).
• Adults: pituitary tumours, surgery, radiotherapy, traumatic brain injury, hypophysitis, Sheehan syndrome, checkpoint inhibitors.
• Adult consequences: increased fat mass, reduced muscle and bone density, dyslipidaemia, reduced quality of life, cardiovascular risk.

• Children: growth velocity below 25th centile, short stature, delayed bone age, hypoglycaemia in neonates, micropenis, truncal obesity, immature face.
• Adults: fatigue, central adiposity, decreased muscle strength, low mood, reduced exercise tolerance.
• Other pituitary deficits.

• Children: auxology, bone age, IGF 1 and IGFBP 3, GH stimulation tests (clonidine, glucagon, arginine, insulin tolerance), peak GH below 7 to 10 micrograms/L; sex steroid priming before testing in prepubertal children; pituitary MRI; genetic testing.
• Adults: IGF 1 (low suggests, normal does not exclude); stimulation test: insulin tolerance test (peak GH below 3 micrograms/L), glucagon test, macimorelin; three or more other pituitary deficits with low IGF 1 can be diagnostic without testing.
• Exclude hypothyroidism, malnutrition, coeliac disease, Turner syndrome.

• Children: somatropin 0.025 to 0.05 mg/kg/day SC nightly (or weekly long acting: somapacitan 0.16 mg/kg, lonapegsomatropin 0.24 mg/kg, somatrogon 0.66 mg/kg); continue until final height; monitor IGF 1, growth, glucose, scoliosis, slipped capital femoral epiphysis.
• Transition: retest at final height; continue if persistent severe GHD.
• Adults: start 0.1 to 0.2 mg daily (lower in older), titrate monthly to IGF 1 in the upper half of normal range; usual maintenance 0.2 to 0.5 mg daily.
• Replace other hormones first (thyroid, cortisol); monitor glucose, lipids, oedema, carpal tunnel.
• Contraindications: active malignancy, intracranial hypertension, proliferative retinopathy.