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Acromegaly

Table of Contents

  • Key Points ⚡
  • Introduction
  • Aetiology
  • Clinical Features
  • Investigations
  • Management
  • Complications
  • References
  • Image References
  • Related Notes
  • Test Yourself

Key Points ⚡

  • Acromegaly: caused by elevated growth hormone (GH) after epiphyseal fusion; contrasts with gigantism (pre-epiphyseal fusion).
  • Aetiology: mostly GH-secreting pituitary adenoma; also pituitary hyperplasia; IGF-1 mediates GH effects.
  • Familial causes: MEN-1, McCune-Albright syndrome, Carney complex.
  • Clinical features: headache, visual changes, altered appearance, weight gain, fatigue, joint pain, voice changes, skin tags, galactorrhoea, erectile dysfunction, reduced libido.
  • Examination findings: bitemporal hemianopia, hypertension, heart failure signs.
  • Investigations: raised IGF-1, failure of GH suppression on OGTT, pituitary MRI, pituitary hormone tests.
  • Management: transsphenoidal surgery (initial), somatostatin analogues (octreotide, lanreotide), GH receptor antagonists (pegvisomant), dopamine agonists (bromocriptine, cabergoline), radiotherapy.
  • Complications: cardiovascular disease, diabetes mellitus, obstructive sleep apnea, colorectal and thyroid cancer, hypopituitarism, carpal tunnel syndrome, osteoarthritis, psychosocial impact.

Introduction

Acromegaly results from prolonged elevated GH levels post-epiphyseal fusion, causing characteristic somatic changes. Gigantism occurs if GH excess is before epiphyseal plate closure. It is usually sporadic, presenting in middle age with equal male and female incidence. Familial forms occur in MEN-1, McCune-Albright syndrome, and Carney complex.

Aetiology

  • Typically caused by a GH-secreting pituitary adenoma.
  • Rarely due to pituitary hyperplasia.
  • IGF-1 is produced in response to GH, mediating its effects via somatostatin regulation.
  • Negative feedback loop is disrupted in acromegaly leading to excess GH.

Clinical Features

History

  • Tumor symptoms: headache, visual changes.
  • Systemic symptoms: appearance changes (frontal bossing, prognathism), weight gain, fatigue, snoring, joint pain, voice changes, skin tags.
  • Prolactin-related: amenorrhoea, galactorrhoea, erectile dysfunction, reduced libido, infertility.
  • Family history: screen for MEN-1, McCune-Albright, Carney complex.

Examination

  • Frontal bossing, macroglossia, prognathism, interdental separation, enlarged hands and feet, thickened skin.
  • Carpal tunnel syndrome.
  • Visual field defects: bitemporal hemianopia from optic chiasm compression.
  • Galactorrhoea, hypertension, heart failure signs.

Investigations

Bedside

  • Visual field testing: bitemporal hemianopia indicates optic chiasm involvement.

Laboratory

  • Raised IGF-1.
  • Oral glucose tolerance test (OGTT): GH levels fail to suppress.
  • Blood glucose, calcium, phosphate, triglycerides may be elevated.
  • Pituitary hormone panel: prolactin, cortisol, TFTs, FSH, LH, oestradiol, testosterone.
  • Serum GH not routinely used due to pulsatility.

Imaging

  • MRI pituitary to detect adenoma.

Management

Surgical

  • Transsphenoidal resection is first-line treatment; potential cure but requires follow-up.

Medical

  • Somatostatin analogues (octreotide, lanreotide): inhibit GH release; reduce tumor size; GI side effects common; gallstones in ~20%.
  • GH receptor antagonist (pegvisomant): blocks IGF-1 synthesis; second-line if somatostatin analogues insufficient; monitor liver function.
  • Dopamine agonists (bromocriptine, cabergoline): suppress GH and prolactin; side effects include nausea, headache.

Radiotherapy

  • Stereotactic gamma-knife radiotherapy used for residual/refractory disease; risk of hypopituitarism.

Long-term Monitoring

  • Clinical signs and symptoms.
  • IGF-1 levels.
  • Pituitary hormones (TFTs, cortisol, prolactin, sex hormones).
  • Repeat MRI for adenoma size.
  • Monitor BP, ECG, echocardiography, sleep study, OGTT.
  • Colonoscopy every 10 years due to increased polyp risk.

Complications

  • Cardiovascular: hypertension, heart failure, stroke, coronary artery disease.
  • Diabetes mellitus.
  • Obstructive sleep apnea.
  • Increased risk of colorectal and thyroid cancers.
  • Hypopituitarism.
  • Carpal tunnel syndrome.
  • Osteoarthritis.
  • Psychosocial morbidity.

References

  • Kumar P, Clark M. Kumar & Clark Clinical Medicine, 9th ed. Elsevier Saunders; 2017.
  • Payne J. Acromegaly | Doctor's Guide. Patient.info; 2016.
  • Dineen R, Stewart P, Sherlock M. Acromegaly – Diagnosis and Clinical Management. QJM; 2016.
  • Adigun O, Nguyen M, Fox T, Anastasopoulou C. Acromegaly. NCBI; 2022.
  • Behari S, Banerji D, Das N, et al. Surgical management of acromegaly: long-term outcomes. Asian J Neurosurg; 2016.
  • Melmed S, Katznelson L. UpToDate; 2022.

Image References

  • Figure 1: Mikael Haggstrom. Endocrine growth regulation. [Public Domain]
  • Figure 2: [Description missing]
  • Figure 3: Philippe Chanson and Sylvie Salenave. Prognathism, maxillary widening, interdental spacing, jaw malocclusion. [CC BY 2.0]
  • Figure 4: RobertB3009. Bitemporal hemianopia. [CC BY-SA 4.0]
  • Addison's Disease (Primary Adrenal Insufficiency)
  • Cushing's Syndrome
  • Diabetes Insipidus
  • Growth Hormone Deficiency
  • Hyperparathyroidism

Test Yourself

  • [Link to quiz or flashcards related to acromegaly]

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