What investigations are typically done after an acromegaly diagnosis?

Investigations After Acromegaly Diagnosis

After an acromegaly diagnosis, patients should undergo a comprehensive set of investigations including pituitary MRI, full hormonal assessment, cardiovascular evaluation, colonoscopy (for those ≥40 years), sleep study, and glucose metabolism testing to assess disease extent and comorbidities. 1, 2

Initial Investigations

Imaging Studies

• Contrast-enhanced pituitary MRI: Essential to identify the GH-secreting adenoma, determine size, invasiveness, and relationship to surrounding structures 1
• Regular MRI surveillance: Particularly important for patients with large residual tumors or those on pegvisomant therapy 2

Hormonal Assessment

• Complete pituitary function testing: To identify any hypopituitarism due to tumor compression or mass effect 1
  • ACTH/cortisol axis
  • TSH/free T4
  • LH/FSH and sex hormones (testosterone/estradiol)
  • Prolactin (co-secretion occurs in some cases)

Biochemical Monitoring

• Regular GH and IGF-1 measurements: To assess disease activity and treatment response 2
  • Baseline levels should be documented before treatment initiation
  • Method-specific and assay-specific normal GH cut-offs should be used 2

Comorbidity Screening

Cardiovascular Assessment

• Echocardiography: To evaluate for acromegalic cardiomyopathy, which progresses through hyperkinetic, hypertrophic, and eventually dilated stages 1
• ECG: To detect arrhythmias and conduction abnormalities
• Blood pressure monitoring: Hypertension is common in acromegaly

Metabolic Evaluation

• Oral glucose tolerance test: To assess for diabetes mellitus 2
• Lipid profile: To evaluate dyslipidemia
• HbA1c: For monitoring of glycemic control

Gastrointestinal Screening

• Colonoscopy: Starting at age 40 for all acromegaly patients due to increased risk of colorectal polyps and cancer 1, 2
  • Repeat colonoscopy intervals depend on findings:
    • Every 3 years if adenoma found at first screening or elevated IGF-1 levels
    • Every 5 years if negative first colonoscopy or only hyperplastic polyps 1

Respiratory Assessment

• Sleep study: To evaluate for sleep apnea, which is highly prevalent in acromegaly 2
• Pulmonary function tests: If respiratory symptoms are present

Musculoskeletal Evaluation

• X-rays or other imaging: For patients with joint pain or suspected arthropathy
• Bone mineral density: To assess for osteoporosis or vertebral fractures

Genetic Testing

• Consider genetic testing in young patients (<30 years), those with family history of pituitary adenomas or endocrine tumors 2
  • Testing for syndromes such as:
    • Multiple Endocrine Neoplasia type 1 (MEN1)
    • Carney complex
    • X-linked acrogigantism
    • McCune-Albright syndrome 1

Monitoring Protocol

Biochemical Monitoring

• GH and IGF-1 levels: Every 3-6 months during treatment adjustment, then every 6-12 months once stable 2
• Pituitary function tests: Annually or as clinically indicated

Imaging Follow-up

• MRI: 3-6 months after surgery, then annually for 3-5 years, and less frequently thereafter if stable
• More frequent MRI: For patients with large residual tumors, especially those on pegvisomant therapy 2

Special Considerations

• Technical difficulties with colonoscopy may occur in acromegaly patients; thorough bowel preparation is essential 1
• Laboratory assay variability can affect results; consistent use of the same assay is recommended 2, 3
• Discordant GH and IGF-1 results occur in approximately 15% of patients and require careful interpretation 2

By implementing this comprehensive investigation protocol, clinicians can effectively assess disease extent, monitor treatment response, and detect comorbidities early, ultimately improving morbidity, mortality, and quality of life outcomes for patients with acromegaly.