Growth Hormone Disorders

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | Example Management | References

Definition

Growth hormone disorders involve abnormalities in the production or action of growth hormone (GH), a peptide hormone secreted by the anterior pituitary gland. These disorders include growth hormone deficiency (GHD) and growth hormone excess, leading to conditions such as dwarfism and gigantism/acromegaly, respectively.

Aetiology

The causes of growth hormone disorders vary:

• Growth Hormone Deficiency (GHD): Can be congenital (genetic mutations) or acquired (tumours, head trauma, infections, radiation therapy).
• Growth Hormone Excess: Usually caused by a pituitary adenoma producing excess GH. In children, this leads to gigantism, and in adults, it causes acromegaly.

Pathophysiology

GH plays a crucial role in growth, metabolism, and tissue repair:

• Growth Hormone Deficiency: Leads to short stature in children and various metabolic disturbances in adults, including increased fat mass, reduced muscle mass, and decreased bone density.
• Growth Hormone Excess: Results in abnormal growth of bones and tissues. In children, it causes excessive longitudinal growth (gigantism), while in adults, it leads to acromegaly, characterised by the enlargement of hands, feet, and facial features.

Risk Factors

• Family history of growth hormone disorders
• Genetic mutations affecting GH production or action
• Pituitary tumours
• Head trauma
• Radiation therapy to the head
• Central nervous system infections

Signs and Symptoms

The clinical manifestations of growth hormone disorders depend on whether there is a deficiency or excess of GH:

• Growth Hormone Deficiency:
  • In children: Short stature, delayed growth and development, increased fat around the waist, delayed puberty.
  • In adults: Reduced muscle mass, increased fat mass, decreased bone density, fatigue, depression, impaired cardiac function.
• Growth Hormone Excess:
  • Gigantism (in children): Abnormally rapid growth, extremely tall stature.
  • Acromegaly (in adults): Enlargement of hands, feet, and facial features, joint pain, thickened skin, coarse facial features, headaches, visual disturbances.

Investigations

• Clinical history and physical examination
• Serum GH levels: Baseline and dynamic tests (e.g., GH stimulation tests for GHD, oral glucose tolerance test for acromegaly).
• Insulin-like growth factor 1 (IGF-1): To assess GH activity over time.
• Magnetic resonance imaging (MRI): To identify pituitary adenomas or other structural abnormalities.
• Bone age assessment: In children with suspected GHD.

Management

Primary Care Management

• Referral to endocrinologist: For diagnosis confirmation and management plan.
• Monitoring: Regular follow-up to assess growth patterns in children and metabolic health in adults.
• Education: Informing patients and families about the condition, treatment options, and the importance of adherence to therapy.

Specialist Management

• Growth hormone replacement therapy: For GHD to promote normal growth in children and improve metabolic health in adults.
• Surgical resection of pituitary adenomas: For patients with GH-secreting tumours.
• Medications:
  • Somatostatin analogues (e.g., octreotide) to inhibit GH release in acromegaly.
  • GH receptor antagonists (e.g., pegvisomant) to block GH action in acromegaly.
• Radiotherapy: For patients with residual or recurrent pituitary adenomas post-surgery.
• Management of complications: Addressing issues such as diabetes, hypertension, and cardiovascular disease in acromegaly.

Example Management for Growth Hormone Disorders

A child diagnosed with growth hormone deficiency presenting with short stature and delayed growth should be referred to an endocrinologist. Management includes growth hormone replacement therapy with regular monitoring of growth patterns, IGF-1 levels, and potential side effects. The family should be educated on the importance of adherence to therapy and the expected outcomes. For an adult with acromegaly due to a pituitary adenoma, initial management may include surgical resection of the tumour, followed by medical therapy with somatostatin analogues or GH receptor antagonists if surgery is not curative.

References

1. NICE. (2024). Growth Hormone Deficiency: Diagnosis and Management. Retrieved from NICE
2. NHS. (2023). Growth Hormone Disorders. Retrieved from NHS
3. British Society for Paediatric Endocrinology and Diabetes (BSPED). (2022). Guidelines for the Management of Growth Hormone Deficiency. Retrieved from BSPED
4. Endocrine Society. (2021). Clinical Practice Guidelines for the Diagnosis and Treatment of Acromegaly. Retrieved from Endocrine Society

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