Treatment Approach for Hypopituitarism
The treatment of hypopituitarism requires hormone replacement therapy for each deficient pituitary hormone, with careful attention to the order of replacement when multiple deficiencies exist. 1
Diagnostic Evaluation
Before initiating treatment, comprehensive evaluation is essential:
Morning laboratory tests (around 8 am) should include 1:
- Thyroid function (TSH, free T4)
- Adrenal function (ACTH, cortisol or 1 mcg cosyntropin stimulation test)
- Gonadal hormones (testosterone in men, estradiol in women, FSH, LH)
- MRI of the sella with pituitary cuts
Diagnostic criteria for hypopituitarism include 1:
- ≥1 pituitary hormone deficiency (TSH or ACTH deficiency required) combined with MRI abnormality, OR
- ≥2 pituitary hormone deficiencies (TSH or ACTH deficiency required) with headache and other symptoms
Treatment Algorithm
Step 1: Prioritize Adrenal Insufficiency Treatment
- If adrenal insufficiency is present, start glucocorticoid replacement FIRST before any other hormone replacement 1
- Physiologic doses of steroids (typically hydrocortisone 15-25 mg/day in divided doses) 1
- Higher doses may be needed for severe headaches, vision changes, or adrenal crisis 1
- All patients with adrenal insufficiency should obtain and carry a medical alert bracelet 1
Step 2: Thyroid Hormone Replacement
- Only after addressing adrenal insufficiency (to avoid precipitating an adrenal crisis) 1
- Levothyroxine replacement for central hypothyroidism 1
- Dosing based on free T4 levels, not TSH (which will be low/normal in central hypothyroidism) 1
Step 3: Sex Hormone Replacement
- Testosterone for men with hypogonadism 1, 2
- Estrogen/progesterone for women with hypogonadism 1, 2
- Particularly important for bone health and quality of life 2, 3
Step 4: Growth Hormone Replacement
- Consider in patients with documented GH deficiency 1
- Particularly important in children who have not completed linear growth 1
- Can improve body composition, exercise capacity, and quality of life in adults 2, 3
Step 5: Antidiuretic Hormone (ADH) Replacement
- Desmopressin for diabetes insipidus if present 2, 3
- Dosing adjusted based on fluid balance, serum sodium levels 3
Special Considerations
Radiotherapy-Induced Hypopituitarism
- Hypopituitarism is common after pituitary radiotherapy 1
- GH deficiency is universal by 5 years post-radiotherapy 1
- Multiple hormone deficiencies develop in ~20% at 5 years and 80% at 10-15 years post-radiotherapy 1
- Requires lifelong monitoring with planned transition to adult services 1
Immune Checkpoint Inhibitor-Induced Hypophysitis
- Presents with headache (85%) and fatigue (66%) 1
- Central hypothyroidism (>90%) and adrenal insufficiency (majority) are most common 1
- Approximately 50% present with panhypopituitarism 1
- Typically requires lifelong hormone replacement 1
Cushing Disease in Remission
- Test for GH deficiency after definitive therapy, especially in children 1
- Monitor pubertal progression to identify hypogonadotropic hypogonadism 1
- Consider bone mineral density assessment prior to adult transition 1
Long-Term Monitoring
- Regular clinical and biochemical monitoring is essential 3, 4
- For Cushing disease in remission: 6-monthly clinical examination, 24h UFC, electrolytes, and morning serum cortisol for at least 2 years 1
- Lifelong annual clinical assessment for all patients with hypopituitarism 1, 3
- Consider monitoring for psychiatric and neurocognitive effects 1
Common Pitfalls to Avoid
- Never start thyroid hormone replacement before addressing adrenal insufficiency, as this can precipitate an adrenal crisis 1
- Don't rely on TSH levels to monitor central hypothyroidism; use free T4 instead 1
- Avoid underdiagnosis of GH deficiency, especially in children who have not completed growth 1
- Remember that hypopituitarism after radiotherapy can develop gradually over years, requiring ongoing surveillance 1
- Be aware that most patients will require lifelong hormone replacement 1, 3