Pituitary adenomas

Differential Diagnosis

• Non-functional
• Prolactinoma (blood level should be ~100 per cm of size)
  • Note that a stalk effect can derepress prolactin release
• Growth hormone
• Others

Investigations

• Rule out adrenal insufficiency, which is the most important and potentially life-threatening effect
  • Should see low cortisol with normal aldosterone
  • AM cortisol <100-150 suggests adrenal insufficiency
  • If 150-400 (indeterminate), then proceed with ACTH stimulation test
• Check other pituitary function
  • TSH and free T4
  • Morning testoserone in men
  • Prolactin
  • IGF-1 (though insensitive for low growth hormone)
    • May need insulin tolerance test
  • Diabetes insipidus