Acromegaly - Diagnosis and Management Summary - GrepMed Handbook
Clinical Presentation:
• Classic Acromegaly: frontal bossing, enlarged jaw (macrognathia), ↑ hand + feet size, coarsening facial features, soft tissue swelling and organomegaly
- c/f ring tightening, ↑ glove & shoe size, ↑ heel-pad thickness, paresthesias (carpal tunnel) and OSA
- Arthralgias, hypertrophic arthropathy
• Insidious onset, often undiagnosed for 10+ years.
- Usually presents ~5th decade → peripheral/acral enlargement
- If GH excess occurs before epiphyseal fusion (children) → Gigantism
• Organomegaly: Visceral organs, macroglossia, goiter, LV hypertrophy, colon (↑polyps & malignancy)
• Cutaneous: hyperhidrosis, hair growth, skin tags, skin thickening, acanthosis nigricans, cutis verticis gyrata.
• Macroadenoma direct effects: Headache (60%), Vision Δs (bitemp hemianopia 10%), HyperPRL (30%), Hypogonad (50%)
• Metabolic: Insulin resist + DM, Hyperphosphatemia (70%)
• ↑Mortality due to CVD & colon malignancy
Pathophysiology:
• Acromegaly occurs secondary to GH hypersecretion.
• GH stimulates liver IGF-1 (somatomedin C) secretion. GH + IGF-1 → multisystemic anabolic effects with acromegaly and organomegaly.
• ~98% - GH-secreting pituitary adenoma (Up to 30% of pituitary adenomas are mixed GH & PRL)
• ~2% - Extrapituitary secretion: pancreatic islet cell tumor, excess GHRH release, central (hypothalamic hamartoma) or peripheral (bronchial/abdominal carcinoid or SCLC).
Differential Diagnosis (Pseudoacromegaly/Acromegaloid): insulin resistance pseudo-acromegaly, obesity, hypothyroidism, pachydermoperiostosis, drugs (phenytoin, minoxidil), genetic (Beckwith Wiedemann syndrome)
Diagnosis and Workup:
• Serum IGF-1 level (↑Sens) - GH levels not useful as levels are variable
- If IGF-1 equivocal: Oral glucose suppression test → ⨁ if failure to suppress GH levels to <1ng/mL.
• Pituitary testing: ↑PRL in mixed adenoma, ↓(TFT, LH, FSH & ACTH) 2/2 adenoma mass effect
• Pituitary MRI+contrast
Management:
• 1st line - Transsphenoidal surgical resection for adenoma
• Medical Tx (non-surgical candidates, adjuvant Tx, or post-op residual dz): Somatostatin analogues (Lanreotide) ± GH receptor antagonist (Pegvisomant) ± D2 agonist (Carbergoline)
• Radiotherapy: Relapse or refractory cases
By Dr. Anuj Thakre (@thakre_anuj)
#Acromegaly #Diagnosis #Management #Endocrinology #Treatment #Pathophysiology
