Immediate Management of Neonatal Panhypopituitarism
Start hydrocortisone immediately before any other hormone replacement therapy in this newborn with panhypopituitarism. 1, 2, 3
Critical First Step: Glucocorticoid Replacement
- Hydrocortisone must be initiated first to prevent life-threatening adrenal crisis, which is the primary cause of excess mortality in hypopituitarism 3
- The recommended dose is 15-20 mg daily in divided doses for adults, with weight-based dosing for neonates (typically 8-10 mg/m²/day in 2-3 divided doses) 1
- Never initiate thyroid hormone replacement before ensuring adequate cortisol replacement, as thyroid hormone increases metabolic demand and can precipitate acute adrenal crisis 1, 2, 4
- In acute presentations with hypoglycemia (common in neonatal panhypopituitarism), cortisol deficiency should be excluded and rapidly treated 5, 6
Sequential Hormone Replacement Protocol
Week 1: Hydrocortisone Only
- Start hydrocortisone immediately upon diagnosis 1, 2
- Monitor for signs of adrenal crisis (hypotension, severe hypoglycemia, electrolyte disturbances) 5
- Educate caregivers on "sick day rules" and stress dosing 5, 2
After 1 Week: Add Thyroid Hormone
- Wait at least 1 week after starting hydrocortisone before initiating levothyroxine 5, 1
- The goal is to achieve free T4 in the upper half of the reference range, as TSH is unreliable in central hypothyroidism 1, 4
- In neonates with congenital hypothyroidism, serum total or free T4 should be maintained in the upper half of normal range during the first three years of life 4
- Monitor free T4 (not TSH) at 2 and 4 weeks after initiation, then every 1-2 months during the first year 4
Growth Hormone: Defer Initial Treatment
- Growth hormone replacement is NOT an emergency and should be deferred until the acute phase is stabilized 6
- In the first year of life, growth hormone deficiency has minimal negative consequences for growth 7
- GH therapy can be considered after 2-3 months of age once cortisol and thyroid replacement are optimized, though FDA approval is for age >2 years 5
- Dynamic GH testing cannot be performed reliably in the neonatal period; diagnosis relies on auxology, MRI findings, and low IGF-1 levels 6
Clinical Monitoring Requirements
Immediate (First 2-4 Weeks)
- Monitor for signs of adrenal crisis: hypotension, hypoglycemia, hyponatremia 5, 3
- Check free T4 at 2 and 4 weeks after starting levothyroxine 4
- Assess feeding tolerance and weight gain 5
Ongoing (First Year)
- Free T4 every 1-2 months (TSH is unreliable in central hypothyroidism) 1, 4
- Morning cortisol and ACTH monthly for first 6 months 2
- IGF-1 if growth concerns develop 2, 6
- Physical examination including growth parameters at each visit 4
Critical Pitfalls to Avoid
- Never start thyroxine before hydrocortisone - this can trigger fatal adrenal crisis 1, 2, 8
- Do not rely on TSH to guide thyroid replacement in central hypothyroidism; use free T4 levels 1, 2, 4
- Do not delay cortisol replacement to "wait and repeat labs" - the diagnosis is already established 6, 3
- Do not assume normal growth in the first year excludes GH deficiency; growth delay becomes apparent after age 1 year 7
Answer to Multiple Choice Question
The correct answer is A: Give hydrocortisone. This must be initiated immediately as the first-line treatment, followed by thyroxine after one week of glucocorticoid coverage. Growth hormone is not an emergency intervention in the neonatal period, and waiting to repeat labs is inappropriate when the diagnosis of panhypopituitarism is already established. 1, 2, 3