What is Hypopituitarism?

The pituitary gland produces insufficient amounts of one or more of its hormones. Think of it as the "master gland" failing, so all the downstream glands (thyroid, adrenals, gonads) don't get proper signals.

Causes:

• Pituitary Tumors: Compress normal tissue.
• Surgery or Radiation: Damage to the pituitary.
• Sheehan's Syndrome: Postpartum hemorrhage.
• Traumatic Brain Injury.
• Lymphocytic Hypophysitis: Autoimmune inflammation.

Which Hormones Are Affected?

• ACTH → Cortisol Deficiency: Fatigue, low blood pressure, nausea (most dangerous deficiency).
• TSH → Hypothyroidism: Fatigue, weight gain, cold intolerance.
• LH/FSH → Hypogonadism: Low sex hormones (missed periods in women; low testosterone in men).
• GH Deficiency: In adults, causes fatigue, increased body fat, decreased muscle mass.
• ADH Deficiency → Diabetes Insipidus: Excessive thirst and urination.

Diagnosis:

• Blood Tests: Measure all pituitary hormones and their target gland hormones.
• Stimulation Tests: ACTH stimulation test, insulin tolerance test.
• MRI: To find the cause.

Treatment:

Hormone replacement for each deficiency:

• Hydrocortisone (cortisol).
• Levothyroxine (thyroid).
• Testosterone or Estrogen (sex hormones).
• Growth Hormone (if deficient and symptomatic).