General Hypopituitarism

Presentation

• Symptoms depend on specific hormone deficiency
  • ↓ FSH/LH
    • impotence (males), amenorrhea (females)
    • late-onset puberty (children)
  • ↓ GH
    • growth delay (children)
    • muscle wasting (adults)
    • hypoglycemia (adults) 
      • GH normally gluconeogenic
  • ↓ TSH
    • weakness
    • constipation
• cold intolerance

Evaluation

• FSH/LH
  • GnRH stimulation test
    • no change in FSH/LH release in hypopituitarism
    • see ↑ in cases of hypothalamic causes
• GH
  • Arginine and sleep stimulation tests
    • no change in GH release in hypopituitarism
    • GH normally released at maximum rate at 5 AM
• TSH
  • TRF stimulation
    • no change in TSH release in hypopituitarism
• ACTH
  • metyrapone test
    • inhibitor of adrenal 11-hydroxylase
      • normally results in ↓ conversion of 11-deoxycortisol to cortisol
      • consequent ↑ in ACTH release and ↑ in 11-deoxycortisol proximal to the inhibited enzymes
    • in cases of hypopituitarism there is no ↑ in ACTH or 11-deoxycortisol
    • in adrenal disease there is an ↑ in ACTH but not 11-deoxycortisol