Growth Hormone Deficiency
GHD is insufficient secretion of Growth Hormone (GH) from the anterior pituitary gland. It may be isolated or part of panhypopituitarism. Causes include genetic mutations, congenital midline defects, trauma, CNS infections, pituitary tumours, or radiotherapy.
Classification:
- ⏳ Congenital – present from birth, often due to genetic or developmental abnormalities.
- ⚡ Acquired – develops later due to injury, tumour, or systemic illness.
- 📌 By age: Childhood vs. Adult onset, with distinct clinical features.
🩺 Clinical Presentation
- 👶 In Children:
- 📉 Growth Failure: Reduced height velocity → short stature.
- 👼 Appearance: Cherubic face, thin hair/skin, ↑ truncal adiposity.
- 🦴 Skeletal: Delayed bone age on X-ray.
- 🩸 Metabolic: Hypoglycaemia (especially if ACTH deficiency co-exists).
- ⏱️ Puberty: Delayed or absent secondary sexual characteristics.
- 👨🦳 In Adults:
- ⚡ Energy/Mood: Fatigue, low exercise tolerance, depression, poor quality of life.
- 💪 Body Composition: ↓ Muscle mass, ↑ central fat, poor physical performance.
- 🦴 Bone Health: Osteopenia/osteoporosis, ↑ fracture risk.
- ❤️ Cardiovascular: Dyslipidaemia, insulin resistance, ↑ CV risk.
🧪 Investigations
- Insulin Tolerance Test (ITT): Gold standard. Failure of GH rise after induced hypoglycaemia confirms GHD.
- IGF-1 levels: Often low, but may be normal in mild disease. Useful screening test.
- Alternative Stimulation Tests: Glucagon stimulation test, clonidine, or arginine test (if ITT contraindicated).
- Pituitary MRI: To detect pituitary adenomas, empty sella, craniopharyngioma, or other sellar masses.
⚕️ Management
- Children: GH replacement therapy (daily subcutaneous injections) → normalise growth velocity and adult height. Continue until epiphyseal closure.
- Adults: GH therapy improves energy, lean body mass, bone density, and psychological wellbeing. Used selectively with proven GHD.
- Monitoring: IGF-1 levels (guide dose), glucose tolerance, lipids, and periodic DXA scans. Watch for side effects (oedema, arthralgia, insulin resistance).
💡 Exam Tip: In children with short stature and delayed bone age, always consider GHD. In adults, think of GHD when fatigue, abdominal obesity, and low IGF-1 are found in the context of pituitary disease.
