Most patients with acromegaly present with florid symptoms, which can surface in various systems. Diagnosing acromegaly involves the recognition of symptoms and assessment of autonomous secretion of growth hormone (GH).8

Symptoms of acromegaly8

• Local tumor effects
• Somatic systems
• Musculoskeletal system
• Skin and gastrointestinal systems
• Cardiovascular system
• Pulmonary system
• Visceromegaly-an increase in the size of the viscera
• Metabolic systems
• Endocrine systems

Diagnosis of acromegaly

Diagnosis is made through a combination of biochemical assays and neuroradiological imaging:6,9

• An IGF-1 assay
• Measuring GH during an Oral Glucose Tolerance Test (OGTT)
• Pituitary magnetic resonance imaging (MRI)

Local tumor effects

• Pituitary enlargement
• Visual-field defects
• Cranial-nerve palsy
• Headache

Somatic systems

• Acral enlargement, including thickness of soft tissue of hands and feet

Musculoskeletal system

• Gigantism
• Prognathism
• Jaw malocclusion
• Arthralgias and arthritis
• Carpal tunnel syndrome
• Acroparesthesia
• Proximal myopathy
• Hypertrophy of frontal bones

Skin and gastrointestinal system

• Hyperhidrosis
• Oily texture
• Skin tags
• Colon polyps

Cardiovascular system

• Left ventricular hypertrophy
• Asymmetric septal hypertrophy
• Cardiomyopathy
• Hypertension
• Congestive heart failure

Pulmonary system

• Sleep disturbances
• Sleep apnea (central and obstructive)
• Narcolepsy

Visceromegaly

• Tongue
• Thyroid gland
• Salivary glands
• Liver
• Spleen
• Kidney
• Prostate

Endocrine and metabolic systems

• Reproduction
  • Menstrual abnormalities
  • Galactorrhea
  • Decreased libido, impotence, low levels of sex hormone-binding globulin
• Multiple endocrine neoplasia type 1
  • Hyperparathyroidism
  • Pancreatic islet-cell tumors
• Carbohydrate
  • Impaired glucose tolerance
  • Insulin resistance and hyperinsulinemia
  • Diabetes mellitus
• Lipid
  • Hypertriglyceridemia
• Mineral
  • Hypercalciuria, increased levels of 25-hydroxyvitamin D3
  • Urinary hydroxyproline
• Electrolyte
  • Low renin levels
  • Increased aldosterone levels
• Thyroid
  • Low thyroxine-binding-globulin levels
  • Goiter

An IGF-1 assay - Measurement of serum insulin-like growth factor (IGF-1) is a reliable indicator of GH status in acromegaly. There should be appropriate age and gender matched reference intervals. Serum IGF-1 is the best biochemical marker of clinical disease activity. The laboratory should participate in an External Quality Assurance Program and should be able to present individual IGF-1 results as a standard deviation score.9

Measuring GH during an Oral Glucose Tolerance Test (OGTT) - GH response to an OGTT offers valuable information when there is a discrepancy between IGF-1 and GH levels. In acromegaly, GH secretion is typically non-suppressible during an OGTT. The criteria for adequate suppression need to be defined for each specific GH assay.9

Pituitary magnetic resonance imaging (MRI) - In 95% of cases, there is a tumor in the pituitary, which is located within the sella turcica-a bony saddle-like formation at the base of the cranium. The sella turcica in acromegalic patients is deformed and increased in volume. Imaging techniques are useful to locate the tumor and to determine its size. Pituitary MRI is the neuroradiological examination of choice for diagnosing acromegaly. A computed tomography scan can also be used to confirm the size of the adenoma and its spread.6